Copyright © Kambiz R. Khojasteh. All rights reserved.
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DESCRIPTION

TSimpleGraph is a visual component, which provides a simple user interface for drawing graphs. The control and its graph objects are fully customizable in the way that let you create almost any kind of graphs.

Currently the control has seven node objects for basic geometric shapes: Triangle, Rhomboid, Rectangle, Round Rectangle, Pentagon, Hexagon, and Ellipse. In addition, by sub classing a class and overriding one or two methods, you can provide your own desired nodes. The line (link) object of the control is very flexible, and can be hook to other objects or connect them together.

By the way, the control has also some methods for supporting Delphi's clipboard and printer objects.

INTERFACE

• Classes
  
  

  TSimpleGraph = class(TCustomControl) TSimpleGraph is a windowed control that provides a canvas for drawing a graph. It also manages relation between graph objects and the application. Key Properties ClipboardFormats: TGraphClipboardFormats TGraphClipboardFormats = set of (cfNative, cfMetafile, cfBitmap) Determines which formats should be used for copying graph contents in to the Windows clipboard. cfNative   CF_SIMPLEGRAPH   Graph copies in to the clipboard as native format. PasteFromClipboard only supports this format. cfMetafile   CF_ENHMETAFILE   Graph copies in to the clipboard as an enhanced metafile. cfBitmap   CF_BITMAP   Graph copies in to the clipboard as a device dependent bitmap.   CommandMode: TGraphCommandMode TGraphCommandMode = (cmViewOnly, cmEdit, cmInsertNode, cmLinkNodes) Determines which kind of commands are available to the user. cmViewOnly   The user cannot modify placement of the objects. cmPan   The user can pan the graph by dragging mouse. cmEdit   The user can modify objects by mouse and/or keyboard. cmInsertNode   The user can insert a new node object. When user inserted a node, this mode automaticalley changes to cmEdit. cmInsertLink   The user can insert a new link object. When user inserted a link, this mode automaticalley changes to cmEdit. CursorPos: TPoint Determines the current mouse cursor position in graph coordinates. DefaultLinkClass: TGraphLinkClass (Read-Only) Determines the class that should be used for a new link object. DefaultNodeClass: TGraphNodeClass (Read-Only) Determines the class that should be used for a new node object. DefaultKeyMap: Boolean Indicates whether the control internally handle the keyboard shortcuts entered by the user. See Keyboard Shortcuts for the default key mapping. DraggingBounds: TRect (Read-Only) Specifies the smallest visual bounding rectangle of the graph objects being dragged in graph coordinates. DraggingObjects: TGraphObjectList Contains the list of graph objects being dragged. The first object in the list is source of the drag, and the rest are objects following the drag. DragSource: TGraphObject (Read-Only) Specifies the object being dragged. DrawOrder: TGraphDrawOrder TDrawOrder = (doDefault, doNodesOnTop, doLinksOnTop) Determines the z-order of objects. doDefault   The objects draw as they ordered in the Objects list. doNodesOnTop   The nodes appear on top of the links. doLinksOnTop   The links appear on top of the nodes. FixedScrollBars: Boolean Determines how range of scroll bars should be calculated. When FixedScrollBars is False, the range of scroll bars determines using the graph bounding rectangle, otherwise the range is calculated using graph constraints bounding rectangle. GraphBounds: TRect (Read-Only) Specifies the smallest visual bounding rectangle of the all visible graph objects in graph coordinates. GraphConstraints: TGraphConstraints Specifies the minimum and maximum coordinates of the objects in the graph. GridColor: TColor Determines the color of the grid. GridSize: TGridSize TGridSize = 4..128 Determines the grid spacing in graph's unit along the x- and y-axis. HideSelection: Boolean Determines whether the visual indication of the selected grpah objects remains when focus shifts to another control. HorzScrollBar: TGraphScrollBar Represents the horizontal scroll bar for the scrolling the graph. LockLinks: Boolean Indicates whether the user can move graph links by mouse or keyboard. LockNodes: Boolean Indicates whether the user can move or resize graph nodes by mouse or keyboard. ObjectAtCursor: TGraphObject (Read-Only) Specifies the last object found under the mouse cursor. Objects: TGraphObjectList Contains the list of graph objects in the graph. ObjectPopupMenu: TPopupMenu Identifies the pop-up menu associated with the graph's objects. MarkerColor: TColor Determines the color of the selection marker. MarkerSize: TMarkerSize TMarkerSize = 3..9 Determines the size of the selection marker in pixels. MinNodeSize: Word Specifies the minimum nodes' with and height in pixels. Modified: Boolean Indicates whether the graph is modified. SelectedObjects: TGraphObjectList Contains the list of selected graph objects in the graph. SelectionBounds: TRect (Read-Only) Specifies the smallest visual bounding rectangle of the selected graph objects in graph coordinates. ShowGrid: Boolean Indicates whether the control shows dot grids on the designer. ShowHiddenObjects: Boolean Indicates whether the control shows graph objects, which are not vissible. SnapToGrid: Boolean Indicates whether the control automatically aligns graph objects on the designer with the nearest gridline. Transparent: Boolean Specifies whether the background of the control is transparent. VertScrollBar: TGraphScrollBar Represents the vertical scroll bar for the scrolling the graph. VisibleBounds: TRect (Read-Only) Specifies the bounding rectangle of the visible part of the graph in graph's unit. Zoom: TZoom TZoom = 5..36863 Specifies the control's zoom factor in percent. Key Events OnAfterDraw: TGraphDrawEvent; TGraphDrawEvent = procedure(Graph: TSimpleGraph; Canvas: TCanvas) of object; Occurs after drawing the graph on the canvas. OnBeforeDraw: TGraphDrawEvent; TGraphDrawEvent = procedure(Graph: TSimpleGraph; Canvas: TCanvas) of object; Occurs just before the graph being drawn on the canvas. OnCanHookLink: TGraphCanHookEvent; TGraphCanHookEvent = procedure(Graph: TSimpleGraph; Link: TGraphLink; GraphObject: TGraphObject; Index: Integer; var CanHook: Boolean) of object; Occurs when an attempt is made to hook a point of the link to an object. OnCanLinkObjects: TGraphCanLinkEvent; TGraphCanLinkEvent = procedure(Graph: TSimpleGraph; Link: TGraphLink; Source, Target: TGraphObject; var CanLink: Boolean) of object; Occurs when an attempt is made to connect two objects together. OnCanMoveResizeNode: TCanMoveResizeNodeEvent; TCanMoveResizeNodeEvent = procedure(Graph: TSimpleGraph; Node: TGraphNode; var NewLeft, NewTop, NewWidth, NewHeight: Integer; var CanMove, CanResize: Boolean) of object; Occurs when an attempt is made to resize or move a node. OnCanRemoveObject: TGraphCanRemoveEvent; TGraphCanRemoveEvent: procedure(Graph: TSimpleGraph; GraphObject: TGraphObject; var CanRemove: Boolean); Occurs just before object being removed. OnCommandModeChange: TNotifyEvent; Occurs when CommandMode is changed. OnGraphChange: TNotifyEvent; Occurs when the graph is changed. OnInfoTip: TGraphInfoTipEvent; TGraphInfoTipEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject; var InfoTip: String) of object; Occurs when the user pauses the mouse over an object in the graph. OnMoveResizeNode = TGraphNodeResizeEvent; TGraphNodeResizeEvent = procedure(Graph: TSimpleGraph; Node: TGraphNode) of object; Occurs when a node is moved or resized.  OnObjectAfterDraw: TGraphObjectDrawEvent; TGraphObjectDrawEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject; Canvas: TCanvas) of object; Occurs after drawing the graph object on the canvas. OnObjectBeforeDraw: TGraphObjectDrawEvent; TGraphObjectDrawEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject; Canvas: TCanvas) of object; Occurs just before the graph object being drawn on the canvas. OnObjectBeginDrag: TGraphBeginDragEvent; TGraphBeginDragEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject; HT: DWORD) of object; Occurs just after the graph object is initiated to drag. Consider that other selected object may follow the drag operation, however this event occurs only for the drag source. OnObjectEndDrag: TGraphEndDragEvent; TGraphEndDragEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject; HT: DWORD; Cancelled: Boolean) of object; Occurs just after the graph object finished to drag. Consider that other selected object may follow the drag operation, however this event occurs only for the drag source. OnObjectContextPopup: TGraphContextPopupEvent; TGraphContextPopupEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject; const MousePos: TPoint; var Handled: Boolean) of object; Occurs when the user right-clicks on a graph object. OnObjectClick: TGraphNotifyEvent; TGraphNotifyEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject) of object; Occurs when user clicks on a graph object. OnObjectDblClick: TGraphNotifyEvent; TGraphNotifyEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject) of object; Occurs when user double clicks on a graph object. OnObjectHook: TGraphHookEvent; TGraphHookEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject; Link: TGraphLink; Index: Integer) of object; Occurs when a link is hooked to a graph object. OnObjectUnhook: TGraphHookEvent; TGraphHookEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject; Link: TGraphLink; Index: Integer) of object; Occurs when a link is unhooked from a graph object. OnObjectInitInstance: TGraphNotifyEvent; TGraphNotifyEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject) of object; Occurs when a new graph object is being created. In this stage, the graph object is not inserted on the graph yet. OnObjectInsert: TGraphNotifyEvent; TGraphNotifyEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject) of object; Occurs when a new graph object is added to the graph. OnObjectRemove: TGraphNotifyEvent; TGraphNotifyEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject) of object; Occurs when a graph object is removed from the graph. OnObjectChange: TGraphNotifyEvent; TGraphNotifyEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject) of object; Occurs when a graph object is changed. OnObjectSelect: TGraphNotifyEvent; TGraphNotifyEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject) of object; Occurs when a graph object is selected/deselected in the graph. Use Selected property of the object to determine whether it is selected or deselected. OnObjectRead: TGraphStreamEvent; TGraphStreamEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject; Stream: TStream) of object; Occurs when property settings of a graph object is being read, and the graph object has some custom data. The event handler can read custom data from the stream passed as parameter. OnObjectWrite: TGraphStreamEvent; TGraphStreamEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject; Stream: TStream) of object; Occurs when property settings of a graph object is being written, and HasCustomData property of the graph object is True. The event handler can write custom data in to the stream passed as parameter. OnObjectMouseEnter: TGraphNotifyEvent; TGraphNotifyEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject) of object; Occurs when the mouse pointer moves over the graph object. OnObjectMouseLeave: TGraphNotifyEvent; TGraphNotifyEvent = procedure(Graph: TSimpleGraph; GraphObject: TGraphObject) of object; Occurs when the mouse pointer moves off from over the graph object. OnZoomChange: TNotifyEvent; Occurs when zoom property changes. Key Methods procedure BeginUpdate; Suspends screen repainting. procedure EndUpdate; Re-enables screen repainting. procedure Draw(Canvas: TCanvas); Draws the graph in its actual size on the given canvas. procedure Print(Canvas: TCanvas; const Rect: TRect); Draws the graph on the canvas in the rectangle specified by the Rect parameter. The Print method maintains the original aspect ratio of the graph. procedure ToggleSelection(const Rect: TRect; KeepOld: Boolean; GraphObjectClass: TGraphObjectClass = nil); Toggles selection state of the objects that intersects the given rectangle. If GraphObjectClass parameter is not nil, the function only toggles selection of graph objects in the specified class type. When KeepOld is True, the function keeps the previous selected objects still selected, otherwise it deselects them. function FindObjectAt(X, Y: Integer; LookAfter: TGraphObject = nil ): TGraphObject; Returns the graph object that contains the specified point. If no graph object found, the return value is nil. The function starts searching from the graph objects behind the graph object specified by the LookAfter parameter. If LookAfter parameter is nil, the search starts from the top most graph object. function FindObjectByID(ID: DWORD): TGraphObject; Returns graph object, which its UniqueID is equal to the value specified by the ID parameter. The function returns nil if search fails. function ForEachObject(Callback: TGraphForEachMethod; UserData: Integer; Selection: Boolean = False): Integer; TGraphForEachMethod = function(GraphObject: TGraphObject; UserData: Integer): Boolean of object; Enumerates all objects (or selected objects) on the graph by passing each object, in turn, to an application-defined callback method specified by the Callback parameter. The function continues until the last object is enumerated or the callback method returns False. The function returns the number of enumerated objects. If the Selection parameter is True, the callback method enumerates only selected objects; otherwise it enumerates all the objects. The UserData parameter specifies a 32-bit, application-defined value to be passed to the callback method. function InsertNode(const Bounds: TRect; ANodeClass: TGraphNodeClass = nil): TGraphNode; Inserts a new node object on the graph, and initiates its bounding rectangle with the rectangle specified by the Bounds paraneter. ANodeClass parameter specifies the node class of the new node object. If ANodeClass is nil, the function creates the node using DefaultNodeClass property. The function returns the new inserted node, or nil on case of failure. function InsertLink(Source, Target: TGraphObject; ALinkClass: TGraphLinkClass = nil): TGraphLink; Inserts a new link object to connect the two objects specified by Source and Target parameters. ALinkClass parameter specifies the class of the new link object. If ALinkClass is nil, the function creates the link using DefaultLinkClass property. The function returns the new inserted link, or nil on case of failure. function InsertLink(Source: TGraphObject; const Pts: array of TPoint; ALinkClass: TGraphLinkClass = nil): TGraphLink; Inserts a new link object, which its breakpoints and endpoint are specified by the Pts parameter. The startpoint of the link, hooks to the object specified by the Source parameter. ALinkClass parameter specifies the class of the new link object. If ALinkClass is nil, the function creates the link using DefaultLinkClass property. The function returns the new inserted link, or nil on case of failure. function InsertLink(const Pts: array of TPoint; Target: TGraphObject; ALinkClass: TGraphLinkClass = nil): TGraphLink; Inserts a new link object, which its startpoint and breakpoints are specified by the Pts parameter. The endpoint of the link, hooks to the object specified by the Target parameter. ALinkClass parameter specifies the class of the new link object. If ALinkClass is nil, the function creates the link using DefaultLinkClass property. The function returns the new inserted link, or nil on case of failure. function InsertLink(const Pts: array of TPoint; ALinkClass: TGraphLinkClass = nil): TGraphLink; Inserts a new link object, which its startpoint, breakpoints, and endpoint are specified by the Pts parameter. ALinkClass parameter specifies the class of the new link object. If ALinkClass is nil, the function creates the link using DefaultLinkClass property. The function returns the new inserted link, or nil on case of failure. procedure Invalidate; Completely repaints control. procedure InvalidateRect(const Rect: TRect); Repaints a rectangular area of the control. Rectangle coordinates are in graph coordinates. procedure ScrollCenter(GraphObject: TGraphObject); procedure ScrollCenter(const Rect: TRect); procedure ScrollCenter(const Point: TPoint); Scrolls a graph object, rectangle, or point into center of the control's client area. procedure ScrollInView(GraphObject: TGraphObject); procedure ScrollInView(const Rect: TRect); procedure ScrollInView(const Point: TPoint); Scrolls a graph object, rectangle, or point into the visible area of the control. function ZoomRect(const Rect: TRect): Boolean; Zooms the view, so that the specified rectangle fits the client area of the control. function ZoomObject(GraphObject: TGraphObject): Boolean; Zooms the view, so that the specified object fits the client area of the control. function ZoomSelection: Boolean; Zooms the view, so that the selected objects fit the client area of the control. function ZoomGraph: Boolean; Zooms the view, so that the graph entirly fits the client area of the control. function ChangeZoom(NewZoom: Integer; Origin: TGraphZoomOrigin): Boolean; TGraphZoomOrigin = (zoTopLeft, zoCenter, zoCursor); Sets zoom factor to the value specified by the NewZoom parameter. The Origin parameter determines how the zoomed area appears on the client area of the control. zoTopLeft   Tries to keep top left cornor of the current view visible. zoCenter   Tries to keep the center of the current view, still centered. zoCursor   Tries to keep the point under cursor, still under cursor. zoCursorCenter   Tries to move the point under cursor to the center of view.   function ChangeZoomBy(Delta: Integer; Origin: TGraphZoomOrigin): Boolean; TGraphZoomOrigin = (zoTopLeft, zoCenter, zoCursor); Changes zoom factor by the value specified by the Delta parameter. The Origin parameter determines how the zoomed area appears on the client area of the control. zoTopLeft   Tries to keep top left cornor of the current view visible. zoCenter   Tries to keep the center of the current view, still centered. zoCursor   Tries to keep the point under cursor, still under cursor. zoCursorCenter   Tries to move the point under cursor to the center of view.   function AlignSelection(Horz: THAlignOption; Vert: TVAlignOption): Boolean; THAlignOption = (haNoChange, haLeft, haCenter, haRight, haSpaceEqually); TVAlignOption = (vaNoChange, vaTop, vaCenter, vaBottom, vaSpaceEqually); Lines up selected objects in relation to each other. The function returns True if at least one object resizes, otherwise returns False. haNoChange   Does not change the alignment of the object. haLeft   Lines up the left edges of the selected objects . haCenter   Lines up horizontally the centers of the selected objects. haRight   Lines up the right edges of the selected objects. haSpaceEqually   Lines up the selected objects horizontally equidistant from each other. vaNoChange   Does not change the alignment of the object. vaTop   Lines up the top edges of the selected objects . vaCenter   Lines up vertically the centers of the selected objects. vaBottom   Lines up the bottom edges of the selected objects. vaSpaceEqually   Lines up the selected objects vertically equidistant from each other.   function ResizeSelection(Horz, Vert: TResizeOption): Boolean; TResizeOption = (roNoChange, roSmallest, roLargest); Resizes selected objects to be exactly the same height or width. The function returns True if at least one object resizes, otherwise returns False. roNoChange   Does not change the size of the components. roSmallest   Resizes the selected objects to the height or width of the smallest selected object. roLargest   Resizes the selected object to the height or width of the largest selected object.   function SnapPoint(const Pt: TPoint): TPoint; Returns the closest grid point to the given point. procedure SnapOffset(const Pt: TPoint; var dX, dY: Integer); Adjusts dX and dY parameters in the way that offseting the point specified by the Pt parameter by these values, moves the point on the closest grid point. function ClientToGraph(X, Y: Integer): TPoint; Converts X and Y pair of values from the client coordinates to the graph cordinates. function GraphToClient(X, Y: Integer): TPoint; Converts X and Y pair of values from the graph coordinates to the client cordinates. function ScreenToGraph(X, Y: Integer): TPoint; Converts X and Y pair of values from the screen coordinates to the graph cordinates. function GraphToScreen(X, Y: Integer): TPoint; Converts X and Y pair of values from the graph coordinates to the screen cordinates. function FindNextObject(StartIndex: Integer; Inclusive, Backward, Wrap: Boolean; GraphObjectClass: TGraphObjectClass = nil): TGraphObject; Call FindNextObject to search for a graph object as type specified by the GraphObjectClass parameter. If the Inclusive parameter is True, the graph object specified by StartIndex is the first item checked. Otherwise, the search starts on the next object. If the Wrap parameter is True, the search continues at the top of z-order if a match has not been found before reaching the bottom. If Backward is False, FindNextObject searches forward through the graph objects in z-order, otherwise it searches backward through the graph objects. function SelectNextObject(Backward: Boolean; GraphObjectClass: TGraphObjectClass = nil): Boolean; Moves the selection to the next selectable graph object as the specified type in the z-order. If Backward is False, SelectNextObject searches forward through the graph objects in z-order, otherwise it searches backward through the graph objects. If SelectNextObject does not locate an appropriate graph object, the current selection will remain unchanged and the function returns False. function ObjectsCount(GraphObjectClass: TGraphObjectClass = nil): Integer; Returns the number of graph objects as the specified type. function SelectedObjectsCount(GraphObjectClass: TGraphObjectClass = nil): Integer; Returns the number of selected graph objects as the specified type. procedure SaveAsMetafile(const Filename: String); Saves the graph to a file as Windows Enhanced Metafile image. procedure SaveAsBitmap(const Filename: String); Saves the graph to a file as a 24bit Bitmap image. procedure LoadFromStream(Stream: TStream); Loads a graph from a stream in to the control. This function clears the previous content of the control. procedure LoadFromFile(const Filename: String); Loads a graph from a file in to the control. This function clears the previous content of the control. procedure SaveToStream(Stream: TStream); Saves the graph in to a stream. procedure SaveToFile(const Filename: String); Saves the graph to a file. procedure MergeFromStream(Stream: TStream; OffsetX, OffsetY: Integer); Loads a graph from a stream and inserts it at the position specified by OffsetX and OffsetY parameters. This functions keeps the old content of the cotrol unchanged. procedure MergeFromFile(const FileName: String; OffsetX, OffsetY: Integer); Loads a graph from a file and inserts it at the position specified by OffsetX and OffsetY parameters. This functions keeps the old content of the cotrol unchanged. procedure CopyToGraphic(Graphic: TGraphic); Copies the graph in to the image specified by the Graphic parameter. procedure CopyToClipboard(Selection: Boolean = True); Copies the selected graph objects to the Clipboard. When Selection parameter is False, the function copies all the graph objects to the Clipboard. See ClipboardFormats property for the supported clipboard formats. function PasteFromClipboard: Boolean; Pastes the contents of the clipboard into the control. If the Clipboard is empty, or its content is not in CF_SIMPLEGRAPH format (cfNative), PasteFromClipboard does nothing, and function returns False. procedure ClearSelection; Resets selection state of all objects. procedure Clear; Removes all the graph objects from the control. class procedure Register(ANodeClass: TGraphNodeClass); overload; class procedure Register(ALinkClass: TGraphLinkClass); overload; Registers a node or link class type for being use in TSimpleGraph. class procedure Unregister(ANodeClass: TGraphNodeClass); overload; class procedure Unregister(ALinkClass: TGraphLinkClass); overload; Unregisters a node or link class type from TSimpleGraph. If an object class type is not registered, loading a graph that uses that kind of object fails. class function NodeClasses(Index: Integer): TGraphNodeClass; Returns the node class type at the specified index. class function LinkClasses(Index: Integer): TGraphLinkClass; Returns the link class type at the specified index. class function NodeClassCount: Integer; Returns the number of registered node class types. class function LinkClassCount: Integer; Returns the number of registered link class types.

  
  

  TGraphConstraints = class(TPersistent) Contains bound constraints of the graph. Key Properties MinLeft: Integer Specifies the minumum horizontal coordinates in pixels. MinTop: Integer Specifies the minumum vartical coordinate ins pixels. MaxRight: Integer Specifies the maximum horizontal coordinates in pixels. MaxBottom: Integer Specifies the maximum vartical coordinates in pixels. BoundsRect: TRect Specifies the bounding rectangle of the constraints. SourceRect: TRect Specifies the rectangle that ConfineOffset method checks its bounds against the constraint's bounds. Owner: TSimpleGraph Determines the owner graph of the constraints. Key Events OnChange: TNotifyEvent; Occurs when the constraints change. Key Methods procedure SetBounds(aLeft, aTop, aWidth, aHeight); Sets the constraints' bounds. function WithinBounds(const Pts: array of TPoint): Boolean; Returns True if all the point specified by the Pts array parameter are within the constraint's bounds. function ConfinePt(var Pt: TPoint): Boolean; Modifies the point specified by the Pt parameter, so that the point confines in bounding rectangle of the constraints. The function returns True if the point is already within the constraint's bounds. function ConfineRect(var Rect: TPoint): Boolean; Modifies the rectangle specified by the Rect parameter, so that the rectangle confines in bounding rectangle of the constraints. The function returns True if the rectangle is already within the constraint's bounds. function ConfineOffset(var dX, dY: Integer; Mobility: TObjectSides): Boolean; TObjectSide = (osLeft, osTop, osRight, osBottom); TObjectSides = set of TObjectSide; Modifies the move/resize offset specified by dX and dY parameters in the way that after moving/resizing the SourceRect, none of its edges go outside of the constraint's bounds. The Mobility parameter determines the edges of the SourceRect, which are about to move/resize. The function returns True if move/resize operation is allowed.

  
  

  TGraphObjectList = class(TPersistent) TGraphObjectList maintains the collection of graph objects that appear in a simple graph control. Key Properties Capacity: Integer Specifies the allocated size of the array of graph objects maintained by the list. Count: Integer (Read-Only) Indicates the number of entries in the list that are in use. Items[Index: Integer]: TGraphObject (Read-Only, Default) Lists all graph objects managed by the TGraphObjectList object. Key Methods procedure Assign(Source: TPersistent); Copies elements of one list to another. procedure Clear; Deletes all items from the list. function Add(Item: TGraphObject); Inserts a new item at the end of the list. The function returns the index of added item. procedure Insert(Index: Integer; Item: TGraphObject); Adds a graph object to the Items array at the position specified by Index. procedure Delete(Index: Integer); Removes the item at the position given by the Index parameter. function Remove(Item: TGraphObject): Integer; Deletes the first reference to the Item parameter from the Items array. The function returns the index of the removed item. procedure Move(CurIndex, NewIndex: Integer); Changes the position of an item in the Items array. function IndexOf(Item: TGraphObject): Integer; Returns the index of the first entry in the Items array with a specified value. function First: TGraphObject; Returns the first item in the Items array, and initialize forward enumeration of the list. If the list is empty, the function returns nil. function Last: TGraphObject; Returns the first item in the Items array, and initialize backward enumeration of the list. If the list is empty, the function returns nil. function Prior: TGraphObject; During emumeration, returns the previous item or nil if begin of list is reached. Before calling this function, Last function should be called to initialize backward enumaration. function Next: TGraphObject; During emumeration, returns the next item or nil if end of list is reached. Before calling this function, First function should be called to initialize forward enumaration. function Push: Boolean; Saves the current enumeration state. function Pop: Boolean; Restores the last saved enumeration state. Key Events OnChange: TGraphObjectListEvent; TGraphObjectListEvent = procedure(Sender: TObject; GraphObject: TGraphObject; Action: TGraphObjectListAction) of object; TGraphObjectListAction = (glAdded, glRemoved, glReordered); Occurs when the list changes. glAdded   A graph object is added to the list. glRemoved   A graph object is removed from the list. glReordered   The index of a graph object in the list is changed.

  
  

  TGrephObjectClass = class of TGraphObject TGraphObject = class(TPersistent) (Abstract) TGraphObject is the common ancestor of all graph objects that can appear in the graph designer. Key Properties Brush: TBrush Determines the color and pattern for filling the background of the graph object. BoundsRect: TRect (Read-Only) Determines the bounding rectangle of the graph object in the graph. Data: Pointer Stores a pointer value as part of the graph object. Dependents[Index: Integer]: TGraphObject (Read-Only) Contains list of graph objects, which their placement on the graph are dependent to this object. DependentCount: Integer (Read-Only) Determines the number of objects, which their placement on the graph are dependent to this object. Dragging: Boolean (Read-Only) Indicates whether the graph object is being dragged. Font: TFont Specifies the font to use when writing text on the graph object. HasCustomData: Boolean If this property set to True, OnObjectWrite event will be called when object properties are being saved. Hint: String Contains the text string that can appear when the user moves the mouse over the graph object. ID: DWORD (Read-Only) Indicates the unique identifier of the object in the graph. LinkInputs[Index: Integer]: TGraphLink (Read-Only) Contains list of graph link objects, which their source is hooked to this object. LinkInputCount: Integer (Read-Only) Determines the number of graph link objects, which their source is hooked to this object. LinkOutputs[Index: Integer]: TGraphLink (Read-Only) Contains list of graph link objects, which their target is hooked to this object. LinkOutputCount: Integer (Read-Only) Determines the number of graph link objects, which their target is hooked to this object. Options: TGraphOptions TGraphOptions = set of (goLinkable, goSelectable, goShowCaption) Specifies various display and behavioral properties of the node. goLinkable   The object can be used as either source or target of a link. goSelectable   User can select the object. goShowCaption   The caption of object is shown.   Owner: TSimpleGraph (Read-Only) Determines the owner of the graph object. Pen: TPen Specifies the kind of pen the graph object uses for drawing lines and outlining shapes. ParentFont: Boolean Determines where the graph object looks for its font information. Selected: Boolean Indicates wheter the graph object is selected. SelectedVisualRect: TRect (Read-Only) Specifies the actual rectangle that the graph object, when is selected, occupies on the graph. Showing: Boolean (Read-Only) Indicates whether the graph object is showing on the graph designer. States: TGraphObjectStates TGraphObjectStates = set of (osCreating, osDestroying, osLoading, osReading, osWriting, osUpdating, osDragging, osDragDisabled) Describes the current state of the object, indicating when a component needs to avoid certain actions. osCreating   The object is beging created. osDestroying   The object is about to be destroyed. osLoading   The object is currently loading. This flag is set when the object is first created and not cleared until the component and all its dependences are fully loaded. osReading   The object is reading its properties from a stream. osWriting   The object is writing its properties in to a stream. osUpdating   The object is begin updated. This flag is set between BeginUpdate and EndUpdate block. osDragging   The object is beging dragged. osDragDisabled   The object currently doesn't accept drag operation. osConverting   The object is either source or target of a type conversion operation.   Tag: Integer Stores an integer value as part of the graph object. Text: String Specifies a text string that identifies the graph object to the user. Visible: Boolean Determines whether the graph object appears on the graph designer. VisualRect: TRect (Read-Only) Specifies the actual rectangle that the graph object occupies on the graph. Key Methods constructor Create(AOwner: TSimpleGraph); Creates an instance of the object and inserts it on the graph specified by AOwner parameter. procedure Assign(Source: TPersistent); Copies the contents of another, similar graph object. procedure AssignTo(Dest: TPersistent); Copies the properties of a graph object to a destination graph object. procedure BeginUpdate; Suspends screen repainting. procedure EndUpdate; Re-enables screen repainting. funcrion CanDelete: Boolean; Returns True if the object can be removed; otherwise returns False. function ContainsPoint(X, Y: Integer): Boolean; Returns True if the point specified by X and Y parameters is inside the object, and object is visible. function ContainsRect(const Rect: TRect): Boolean; Returns True if any part of the rectangle specified by the Rect parameter is inside the object, and object is visible. function HitTest(const Pt: TPoint): DWORD; Determines which object's component is at the point specified by the Pt parameter. Depending on the object type, the return value can be can be one or more of the following values: VALUE MEANING SCOPE GHT_NOWHERE The point is not on the object. TGraphObject GHT_TRANSPARENT The point is on the object, but the object is not selectable. TGraphObject GHT_LEFT The point is on left side of the object. TGraphNode GHT_TOP The point is on top side of the object. TGraphNode GHT_RIGHT The point is on right side of the object. TGraphNode GHT_BOTTOM The point is on bottom side of the object. TGraphNode GHT_TOPLEFT The point is on top left corner of the object. TGraphNode GHT_TOPRIGHT The point is on top right corner of the object. TGraphNode GHT_BOTTOMLEFT The point is on bottom left corner of the object. TGraphNode GHT_BOTTOMRIGHT The point is on bottom right corner of the object. TGraphNode GHT_CLIENT The point is on the body of the object. TGraphObject GHT_CAPTION The point is on the caption of the object. TGraphObject GHT_POINT The point is on one of the object's control points. The high order word of the value contains index of the point. TGraphLink GHT_LINE The point is on one of the object's lines. The high order word of the value contains index of the line. TGraphLink   function ConvertTo(AnotherClass: TGraphObjectClass): TGraphObject; Converts the graph object to another graph object type. If the graph object is a link, the new class type must be a link, and if the graph object is a node, the new class type must be a node.. If function succeeds, it releases the old instance and returns reference to the new instance. If function fails, it returns reference the old instance. procedure BringToFront; Puts the graph object in front of all other graph objects. procedure SendToBack; Puts the graph object behind all other graph objects. procedure LoadFromStream(Stream: TStream); Loads the graph object from a stream. procedure SaveToStream(Stream: TStream); Saves the graph object in a stream. procedure Invalidate; Repaints the graph object. class funtion IsNode: Boolean; Returns True of the graph object is a node. class funtion IsLink: Boolean; Returns True of the graph object is a link. funtion IsLocked: Boolean; Returns True if the graph object is locked by the owner. function Delete: Boolean; Removes the graph object. Returns False on failure, otherwise returns True. Any reference to a deleted object is invalid and raises AV exception. function BeginDrag(const Pt: TPoint; HT: DWORD = $FFFFFFFF): Boolean; Initiates the graph object for dragging. The drag origion is specified by the Pt parameter, and the object's component that should be dragged is specified by the HT parameter (see HitTest method). Consider that all or some of other selected objects may follow the drag operation. If HT parameter is $FFFFFFFF, the function finds the object's component by itself. function DragBy(dX, dY: Integer; SnapToGrid: Boolean): Boolean; Moves the object's component defined by BeginDrag method by the amout specified by dX and dY parameters. The SnapToGrid parameter specifies whether the object's component should be snapped to grid or no. function DragTo(const Pt: TPoint; SnapToGrid: Boolean): Boolean; Moves the object's component defined by BeginDrag method to the point specified by the Pt parameter. The SnapToGrid parameter specifies whether the object's component should be snapped to grid or no. function EndDrag(Accept: Boolean): Boolean; Stops dragging operation. If the Accept parameter is True, the modifications caused by the drag operation will be accepted. Otherwise, the modifications will be ignored and the dragged object resets to its state before calling to BeginDrag.

  
  

  TGraphLinkClass = class of TGraphLink TGraphLink = class(TGraphObject) TGraphlink is the base class for all link objects on a graph. Key Properties BeginStyle: TLinkBeginEndStyle TLinkBeginEndStyle = (lsNone, lsArrow, lsDot) Determines the style of the startpoint. lsNone   No style. lsArrow   An arrow will be displayed . lsArrowSimple   A simple arrow will be displayed. lsCircle   A circle will be dislayed. lsDiamond   A diamond will be displayed.   BeginSize: Byte Determines the size of the startpoint's style. EndStyle: TLinkBeginEndStyle TLinkBeginEndStyle = (lsNone, lsArrow, lsDot) Determines the style of the endpoint. lsNone   No style. lsArrow   An arrow will be displayed . lsArrowSimple   A simple arrow will be displayed. lsCircle   A circle will be dislayed. lsDiamond   A diamond will be displayed.   EndSize: Byte Determines the size of the endpoint's style. Source: TGraphObject Determines the source of the connection if any. If Source is not nil, the startpoint of the link hooks to the source object. Target: TGraphObject Determines the target of the connection if any. If Target is not nil, the endpoint of the link hooks to the target object. LinkOptions: TGraphLinkOptions TGraphLinkOptions = set of (gloFixedStartPoint, gloFixedEndPoint, gloFixedBreakPoints, gloFixedAnchorStartPoint, gloFixedAnchorEndPoint) Specifies various display and behavioral properties of the link. gloFixedStartPoint   The startpoint of the link cannot be relocated. gloFixedEndPoint   The endpoint of the link cannot be relocated. gloFixedBreakPoints   The breakpoints of the link cannot be relocated. gloFixedAnchorStartPoint   If the startpoint of the link hooks to a node, the anchor point is fixed to the center of the node. If the startpoint of the link hooks to another link, for the links with odd breakpoints the anchor point is the innermost breakpoint and for the links with even breakpoints the anchor point is center of the innermost segment. gloFixedAnchorEndPoint   If the endpoint of the link hooks to a node, the anchor point is fixed to the center of the node. If the endpoint of the link hooks to another link, for the links with odd breakpoints the anchor point is the innermost breakpoint and for the links with even breakpoints the anchor point is center of the innermost segment.   Points[Index: Integer]: TPoint Contains zero base array of link's points (startpoint, breakpoints, and endpoints). PointCount: Integer (Read-Only) Determines the number of points in the Points array. Polyline: TPoints TPoints = array of TPoint The array of link's points. TextPosition: Integer Indicates the index of the line, which the caption of the link aligns to it. If this property set to -1 (default), the longest line will be selected. TextSpecing: Integer Determines the distance between text and line. Key Methods constructor CreateNew(AOwner: TSimpleGraph; ASource: TGraphObject; const Pts: array of TPoint; ATarget: TGraphObject); Initiates a new instance of the class with the given parameters. ASource and ATarget parameters can be nil, and Pts parameter can be an empty array. function AddPoint(const Pt: TPoint): Integer; Inserts a point at the end of point list. procedure InsertPoint(Index: Integer; const Pt: TPoint); Inserts a point in the point list at the specified index. procedure RemovePoint(Index: Integer); Deletes the point specified by its index in the point list. function IndexOfPoint(const Pt: TPoint; Neighborhood: Integer = 0): Integer; Returns index of the point in the point list, or -1 if the point is not found. The Neighborhood parameter determines the tolerance of comparison in pixels. function AddBreakPoint(const Pt: TPoint): Integer; Inserts a breakpoint at the specified point on a line of the link. The function returns the index of the inserted point in the point list, or -1 if the point is not close to a line of the link. function NormalizeBreakPoints(Options: TLinkNormalizeOptions): Boolean; TLinkNormalizeOptions = set of (lnoDeleteSamePoint, lnoDeleteSameAngle); Passes through the list of points and delete useless ones. The function returns True if at least one point is deleted. lnoDeleteSamePoint   If some breakpoints are very close to each other, only one of them will be kept and the rest will be deleted. lnoDeleteSameAngle   For the edges, which make almost a straight line, the intermediate breakpoints will be deleted.   function IsFixedPoint(Index: Integer; HookedPointsAsFixed: Boolean): Boolean; Returns True if the point specified by its index is a fixed point (see LinkOptions). If the HookedPointsAsFixed parameter is True, the hooked points will also consider as fixed. function IsHookedPoint(Index: Integer): Boolean; Returns true if the point specified by its index is hooked to a graph object. function HookedObjectOf(Index: Integer): TGraphObject; Returns the graph object, which the point specified by its index is hooked to. If the point is not hooked, the function returns False. function HookedIndexOf(GraphObject: TGraphObject): Integer; Returns the index of the point, which is hooked to the specified graph object, or -1 if there is no hook. function HookedPointCount: Integer; Returns the number of points that are hooked to a graph object. function CanHook(Index: Integer; GraphObject: TGraphObject): Boolean; Returns True if the point specified by its index can hook to the specified graph object. function Hook(Index: Integer; GraphObject: TGraphObject): Boolean; Hooks the point specified by its index to the specified graph object. The function returns True on success, otherwise returns False. function Unhook(GraphObject: TGraphObject): Integer; Unhooks the point which is hooked to the specified graph object. The function returns the index of the point, which is unhooked, or -1 on failure. function Unhook(Index: Integer): Boolean; Unhooks the point specified by its index. The function returns True on success, otherwise returns False. function CanLink(ASource, ATarget: TGraphObject): Boolean; Returns True if the link can be used to connect two specified graph objects together. function Link(ASource, ATarget: TGraphObject): Boolean; Uses the link to establish a connection between two specified graph objects. The function returns True on success, otherwise returns False. function CanMove: Boolean; Returns True if all points of the link can move freely. function Rotate(const Angle: Double; const Origin: TPoint): Boolean; Rotates the link around the point specified by the Origin parameter, and the angle specified by Angle parameter in radians. The function returns True on success or False on any failure. function Scale(const Factor: Double): Boolean; Scales the link by the specified factor. A factor bigger than one scales up the link, and a positive factor less than one scales it down. The function returns True on success or False on any failure. procedure Reverse; Reverse the order of the points, and toggles values of Source and Target properties.

  
  

  TGraphNodeClass = class of TGraphNode TGraphNode = class(TGraphObject) (Abstract) TGraphNode is the base class for all node objects on a graph. Key Properties Alignment: TAlignment TAlignment = (taLeftJustify, taRightJustify, taCenter) Controls the horizontal placement of the text within the node. taLeftJustify   Text is left-justified: Lines all begin at the left edge of the node. taCenter   The text is centered centered in the node. taRightJustify   Text is right-justified: Lines all end at the right edge of the node.   Layout: TTextLayout TTextLayout = (tlTop, tlCenter, tlBottom) Specifies the vertical placement of the text within the node. tlTop   The text appears at the top of the node. tlCenter   The text is vertically centered in the node. tlBottom   The text appears along the bottom of the node. Margin: Integer Determines the margin of the text from edges of the node. Left: Integer Specifies the X coordinate of the top left corner of the node in graph's unit. Top: Integer Specifies the Y coordinate of the top left corner of the node in graph's unit. Width: Integer Specifies the horizontal size of the node in graph's unit. Height: Integer Specifies the vertical size of the node in graph's unit. Background: TPicture Determines the background image of the node. BackgroundMargins: TRect Determines the relative margins of the background image as percent of the node's width and height. NodeOptions: TGraphNodeOptions TGraphNodeOptions = set of (gnoMovable, gnoResizable, gnoShowBackground) Specifies various display and behavioral properties of the node. gnoMovable   The node can be moved. gnoResizable   The node can be resized. gnoShowBackground   The background image of the node is visible.   Key Methods constructor CreateNew(AOwner: TSimpleGraph; const Bounds: TRect); Creates an instance of the class and intiates bounding rectangle of the node by rectangle specified by the Bounds parameter. procedure SetBounds(aLeft, aTop, aWidth, aHeight: Integer); Sets the Left, Top, Width, and Height properties all at once. procedure CanMoveResize(var NewLeft, NewTop, NewWidth, NewHeight: Integer; out CanMove, CanResize: Boolean); Determines whether the node can be moved or resized.

  
  

  TPolygonalNode = class(TGraphNode) (Abstract) TPolygonalNode is the base class for all polygon shape nodes. To define a new polygon shape node, subclass TPolygonalNode and override the DefineVertices method. Key Properties Vertices: TPoints (Read-Only) TPoints = array of TPoint Contains the list of polygon's vertices.

  
  

  TRoundRectangularNode = class(TGraphNode) TRoundRectangularNode reperesents a round rectangle shape node.

  
  

  TEllipticNode = class(TGraphNode) TEllipticNode reperesents an ellipse shape node.

  
  

  TTriangularNode = class(TPolygonalNode) TTriangularNode reperesents an triangle shape node.

  
  

  TRectangularNode = class(TPolygonalNode) TRectangularNode reperesents a rectangle shape node.

  
  

  TRhomboidalNode = class(TPolygonalNode) TRhomboidalNode reperesents a rhomboid shape node.

  
  

  TPentagonalNode = class(TPolygonalNode) TPentagonalNode reperesents a pentagon shape node.

  
  

  THexagonalNode = class(TPolygonalNode) THexagonalNode reperesents a hexagon shape node.

  
  

  TGraphScrollBar = class(TPersistent) TGraphScrollBar displays and manages a horizontal or vertical scroll bar on the graph designer. Properties of TGraphScrollBar are similar to Delphi's TControlScrollBar.

  
  

  TMemoryHandleStream = class(TMemoryStream) TMemoryHandleStream is a stream that stores its data in dynamic memory allocated in the Windows global heap. It has all of properties and methods of its ancestor class, which is TMemoryStream. In addition, interface of this stream provides global handle of the allocated memory, which can be used in Windows API functions those need a handle to this handle. Key Properties Handle: Boolean (Read-Only) Handle to the global memory. ReleaseHandle: Boolean Indicates whether the stream releases the memory handle when it is no longer needed. If this property is set to False, it is your responsibility to release the handle by calling GlobalFree (Windows API). As default the value of this property is False. Key Methods constructor Create(MemHandle: THandle); Instantiates a TMemoryHandleStream object. Create constructor initializes the stream using the MemHandle parameter. MemHandle parameter can be zero.

  
  

  TCanvasRecall = class(TObject) TCanvasRecall stores the properties of a canvas object so that they can be restored at a later time. Key Properties Reference: TCanvas Indicates the reference canvas that is managed by the TCanvasRecall instance. Assigning a canvas to this property causes the TCanvasRecall object retrieves the property settings of the old reference canvas, and stores the property settings of the new reference canvas. Key Methods constructor Create(AReference: TCanvas); Instantiates a TCanvasRecal object, and stores properties of the canvas specified by the AReference parameter for future retrieval. When TCanvasRecall instance destroys, it automatically retrieves the old properties of the reference canvas. AReference parameter can be nil. procedure Store; Saves the current property settings of the Reference canvas. procedure Retrieve; Restores the old property settings of the Reference canvas.

  
  

  TCompatibleCanvas = class(TCanvas) TCompatibleCanvas reperesents a canvas compatible to the screen device context.

  
  
  
• Global Procedures
  
  

  WrapText(Canvas: TCanvas; const Text: String; MaxWidth: Integer): String; Breaks text between words if a word would extend the specified width. Canvas is the drawing surface on which the resulting text is to be rendered. It is used to determine font metrics.

  
  

  function MinimizeText(Canvas: TCanvas; const Text: String; const Rect: TRect): String; Breaks words and replaces part of the given text with ellipses, if necessary, so that the result fits in the specified rectangle. Canvas is the drawing surface on which the resulting text is to be rendered. It is used to determine font metrics.

  
  

  function IsBetween(Value: Integer; Bound1, Bound2: Integer): Boolean; If the value specified by the Value parameter is between two values specified by Bound1 and Bound2, the function returnes True, otherwise it returns False.

  
  

  function TransformRgn(Rgn: HRGN; const XForm: TXForm): HRGN; Returns a copy of region specified by the Rgn parameter, which is transformed by the transform matrix specified by the XForm parameter.

  
  

  function NormalizeAngle(const Angle: Double): Double; Converts the angle specified by the Angle parameter, so that it falls in the range from -Pi to Pi radians.

  
  

  function EqualPoint(const Pt1, Pt2: TPoint): Boolean; Returns True if both points passed as parameter are equal.

  
  

  procedure TransformPoints(var Points: array of TPoint; const XForm: TXForm); Transforms points specified by the Points parameter with the transform marix specifies by the XForm parameter.

  
  

  procedure RotatePoints(var Points: array of TPoint; const Angle: Double; const OrgPt: TPoint); Rotates points specified by the Points parameter around the point specified by the OrgPt parameter. The amount of rotation specifies by the Angle parameter, and is in radians.

  
  

  procedure ScalePoints(var Points: array of TPoint; const Factor: Double; const RefPt: TPoint); Scales distance of points specified by the Points parameter from the point specified by the RefPt parameter. The amount of scale specifies by the Factor parameter.

  
  

  procedure ShiftPoints(var Points: array of TPoint; dX, dY: Integer; const RefPt: TPoint); Moves points specified by the Points parameter according to their placement relative to the point specified by the RefPt parameter. The amount of movement specifies by dX and dY parameters. Positive values of dX and dY parameters cause the points go far from the reference point, and negative values cause the point go toward the refrence point.

  
  

  procedure OffsetPoints(var Points: array of TPoint; dX, dY: Integer); Moves the specified points by the specified offsets.

  
  

  function CenterOfPoints(var Points: array of TPoint): TPoint; Returns the center point of the specified points.

  
  

  function BoundsRectOfPoints(var Points: array of TPoint): TRect; Returns the bounding rectangle of the specified points.

  
  

  function NearestPoint(const Points: array of TPoint; const RefPt: TPoint; out NearestPt: TPoint): Integer; Returns the index of the point in the array, which is the nearest to the reference point. Also, the nearest point will be copied in to the NearestPt parameter.

  
  

  function MakeSquare(const Center: TPoint; Radius: Integer): TRect; Returns a square (rectangle) that is reperesented by its center point and radius.

  
  

  function MakeRect(const Corner1, Corner2: TPoint): TRect; Returns a rectangle that is reperesented by its two corner points.

  
  

  function CenterOfRect(const Rect: TRect): TPoint; Returns the center point of the rectangle specified by Rect parameter.

  
  

  procedure UnionRect(var Rect1: TRect; const Rect2: TRect); Calculates the union of two rectangles specified by Rect1 and Rect2 parameters, and sets the result in Rect1. This procedure suppose none of two rectangles are empty.

  
  

  procedure IntersectRect(var Rect1: TRect; const Rect2: TRect); Calculates the intersection of two rectangles specified by Rect1 and Rect2 parameters, and sets the result in Rect1. This procedure suppose none of two rectangles are empty.

  
  

  function OverlappedRect(const Rect1, Rect2: TRect); Returns True if two rectangles has common area, otherwise returns False.

  
  

  function LineLength(const LinePt1, LinePt2: TPoint): Double; Returns lenght of the line represented by its two endpoints as LinePt1 and LinePt2 parameters.

  
  

  function LineSlopeAngle(const LinePt1, LinePt2: TPoint): Double; Returns the slope angle in radians of the line that passes through the points represented by LinePt1 and LinePt2 parameters.

  
  

  function DistanceToLine(const LinePt1, LinePt2: TPoint; const QueryPt: TPoint): Double; Returns the distance of a point specified by the QuaryPt parameter from the line represented by its two endpoints as LinePt1 and LinePt2 parameters.

  
  

  function NearestPointOnLine(const LinePt1, LinePt2: TPoint; const RefPt: TPoint): TPoint; Returns the point on the line represented by its two endpoints as LinePt1 and LinePt2 parameters, which is the nearest to the point specified by the RefPt parameter.

  
  

  function NextPointOfLine(const LineAngle: Double; const ThisPt: TPoint; const DistanceFromThisPt: Double): TPoint; Returns the point on the line reperesented by its slope angle as LineAngle parameter and a passing point as ThisPoint parameter, which its distance from the point specified by the ThisPt parameter is equal to DistanceFromThisPoint parameter. The LineAngle parameter is in radians.

  
  

  function IntersectLines(const Line1Pt: TPoint; const Line1Angle: Double; const Line2Pt: TPoint; const Line2Angle: Double; out Intersect: TPoint): Boolean ; If the two specified lines intersect each other, the function returns True and sets the Intersect parameter to the intersection point. Otherwise, the function returns False. The Line1Angle and Line2Angle parameters shold be in range from -Pi to Pi radians.

  
  

  function IntersectLineRect(const LinePt: TPoint; const LineAngle: Double; const Rect: TRect): TPoints; Retruns a dynamic array of points containing the intersection coordinates of the rectangle specified by the Bounds parameter and the line specified by LinePt and LineAngle parameters. The LineAngle parameter shold be in range from -Pi to Pi radians.

  
  

  function IntersectLineRoundRect(const LinePt: TPoint; const LineAngle: Double; const Bounds: TRect; CW, CH: Integer): TPoints; Retruns a dynamic array of points containing the intersection coordinates of the round rectangle specified by the Bounds, CW, and CH parameters and the line specified by LinePt and LineAngle parameters. The LineAngle parameter shold be in range from -Pi to Pi radians.

  
  

  function IntersectLineEllipse(const LinePt: TPoint; const LineAngle: Double; const Bounds: TRect): TPoints; Retruns a dynamic array of points containing the intersection coordinates of the ellipse specified by the Bounds parameter and the line specified by LinePt and LineAngle parameters. The LineAngle parameter shold be in range from -Pi to Pi radians.

  
  

  function IntersectLinePolygon(const LinePt: TPoint; const LineAngle: Double; const Vertices: array of TPoint): TPoints; Retruns a dynamic array of points containing the intersection coordinates of the polyline specified by its vertices as Vertices parameter and the line specified by LinePt and LineAngle parameters. The LineAngle parameter shold be in range from -Pi to Pi radians.

  
  

  function IntersectLinePolyline(const LinePt: TPoint; const LineAngle: Double; const Vertices: array of TPoint): TPoints; Retruns a dynamic array of points containing the intersection coordinates of the polygon specified by its vertices as Vertices parameter and the line specified by LinePt and LineAngle parameters. The LineAngle parameter shold be in range from -Pi to Pi radians.

KEYBOARD SHORTCUTS

GENERAL
CTRL	In conjunction with some actions, toggles snap to gird mode on/off.
TAB	Selects the next selectable object.
SHIFT+TAB	Selectes the previous selectable object.
LEFT	Moves left selected and movable objects.
RIGHT	Moves right selected and movable objects.
UP	Moves up selected and movable objects.
DOWN	Moves down selected and movable objects.




NODES
SHIFT+LEFT	Decreases width of selected and resizable nodes.
SHIFT+RIGHT	Increases width of selected and resizable nodes.
SHIFT+UP	Decreases height of selected and resizable nodes.
SHIFT+DOWN	Increases height of selected and resizable nodes.

MOUSE ACTIONS

GENERAL
CLICK	Selects the clicked object if it is selectable, and clears previous selection.
SHIFT+CLICK	Toggles selection of the clicked object, and keeps the old selection. If the object is not selectable, it would not be selected.




DESIGNER
DRAG	Selects selectable objects in the marked area, and clears previous selection. Holding CTRL key down causes only node object be selected.
SHIFT+DRAG	Toggles selection of the objects in the marked area, and keeps the old selection unchanged. If any object is not selectable, it would not be selected. Holding CTRL key down causes only selection of node objects toggles.
ALT+DRAG	Zooms the marked area in.




NODES
DRAG CLINET	If the node is movable, moves the node.
DRAG MARKER	If the node is resizable, resize the node according to the dragging marker.




LINKS
DRAG LINE/CAPTION	If the link can be moved, moves the link.
DRAG POINT	If the point is not fixed, moves the point. If the point is an endpoint, and ALT key is not down, dropping the point on an object establishes a link.
ALT+CLICK POINT	If the point is not fixed, removes the point.
ALT+CLICK LINE	If the link is not marked as fixed, inserts a new breakpoint at the clicked coordinates.
RIGHT+CLICK	If a point is dragging, inserts a new breakpoint. The source point of the drag action, keeps its dragging state.

HISTORY

• Version 2.91 (January 25, 2013)
  • Fixed a bug in wrapping text (Thanks to Oleg).

• Version 2.90 (April 27, 2013)
  • Fixed the bug that causing some random characters appear on caption of links.
  • Improved positioning of caption of links.

• Version 2.81 (January 6, 2013)
  • Fixed the compatibility issues with Delphi XE2 and XE3.

• Version 2.80 (June 2, 2011)
  • Added two new options gloFixedAnchorStartPoint and gloFixedAnchorEndPoint to the LinkOptions property of TGraphLink. These options control whether the hooked links should be anchored to a fixed point on the target object or not.

• Version 2.72 (February 2, 2009)
  • The malfunction in changing Left, Top, Width, and Height properties of TGraphNode inside a BeginUpdate/EndUpdate block is fixed.

• Version 2.71 (January 16, 2009)
  • Re-entrance problem in repositioning of hooked objects is fixed (Thanks to cml0816).
  • Problem in selecting horizontal and vertical links with one pixel width is fixed (Thanks to cml0816).
  • Added Push and Pop methods to TGraphObjectList class.

• Version 2.70 (November 14, 2008)
  • Support for Delphi 2009 added.
  • Fixed bug in NormalizeBreakPoints method of TGraphLink class (Thanks to liu8670).
  • Fixed bug in ZoomRect method (Thanks to Choe, Cheng-Dae).

• Version 2.62 (May 15, 2007)
  • Fixed the compatibility issue with Delphi 5.

• Version 2.61 (March 30, 2006)
  • Fixed a bug in managing mouse while CommandMode is cmViewOnly.

• Version 2.60 (March 29, 2006)
  • Added OnObjectMouseEnter and OnObjectMouseLeave events to TSimpleGraph.
  • Added DragSource and ObjectAtCursor properties to TSimpleGraph.
  • Added ResizeSelection method to TSimpleGraph.

• Version 2.50 (March 26, 2006)
  • Added OverlappedRect as global procedure.
  • Added Transparent property to TSimpleGraph.
  • Added ChangeZoom and ChangeZoomBy methods to TSimpleGraph.
  • Added AlignSelection method to TSimpleGraph.
  • Fixed a bug in drawing child controls.
  • Fixed a bug in calculating range of scroll bars when the control had aligned child controls.

• Version 2.40 (March 22, 2006)
  • Fixed a bug in scrolling the graph by keyboard.
  • Fixed a bug in TGraphObjectList.Assign method.

• Version 2.30 (March 21, 2006)
  • Added TCompatibleCanvas class.
  • Added cmPan to possible values of CommadMode properties.
  • Added OnMoveResizeNode event.
  • Fixed a bug in FindObjectAt method.
  • Fixed a bug in triggering some events while loading or clearing the graph.

• Version 2.20 (March 19, 2006)
  • Added SourceRect property to TGraphConstraints.
  • Fixed a bug in merging graphs.

• Version 2.10 (March 18, 2006)
  • Added TCanvasRecall class.
  • Added UnionRect and IntersectRect as global procedures.
  • Added ClipboardFormats property to TSimpleGraph.
  • Added DraggingObjects and DraggingBounds property to TSimpleGraph.
  • Added ScrollCenter method to TSimpleGraph.
  • Added ScreenToGraph and GraphToScreen, SnapPoint, and SnapOffset methods to TSimpleGraph.
  • Added FindObjectByID, and ForEachObject methods to TSimpleGraph.
  • Added SaveAsBitmap, CopyToGraphic methods to TSimpleGraph.
  • Added MergeFromStream and MergeFromFile methods to TSimpleGraph.
  • Added InvalidateRect method to TSimpleGraph.
  • Added OnObjectInitInstance, OnObjectChange, and OnCanRemoveObject events to TSimpleGraph.
  • Added OnObjectRead and OnObjectWrite events to TSimpleGraph.
  • Added HasCustomData property to TGraphObject.
  • Added CanDelete method to TGraphObject.
  • Added Invalidate method to TGraphObject.
  • Added IsNode class method to TGraphObject.
  • Added States, ID, and Data properties to TGraphObject.
  • Added missing AssignTo method to TGraphObject.
  • Added Dependents and DependentCount properties to TGraphObject.
  • Added LinkInputs, LinkInputCount, LinkOutputs, and LinkOutputCount to TGraphObject. Refer to the graph theory, for a node (vertex), these properties are equivalent to input edges, indegree (deg^-), output edges, and outdegree (deg⁺) of the node.
  • Added VisualRect and SelectedVisualRect properties to TGraphObject.
  • Added Create constructor to TGraphObject. Therefore, since now an object can be inserted in a graph directly.
  • Added CreateNew constructor to TGraphLink.
  • Added CreateNew constructor to TGraphNode.
  • Added DragBy method to TGraphObject.
  • Altered prototype of BeginDrag and DragTo methods of TGraphObject.
  • Altered the return value of ConvertTo method of TGraphObject.
  • Altered TGraphObjectList class. The new implementation provides a mechanism to safely enumerate graph objects without beging worry about the items which could be deleted during the enumeration.
  • Altered OnObjectBeginDrag and OnObjectEndDrag events in the way that provide mode information about the dragging object.
  • Altered zooming properties. The current zoom range is from 5% to 36863%. In the other hand, because of adding OnMouseWheelDown and OnMouseWheelUp events to TSimpleGraph, the control does not change the zoom factor internally. Because of these changes, ZoomMin, ZoomMax, and ZoomStep properties were obsolete and removed.
  • Altered prototype of FindObjectAt method of TSimpleGraph. I replaced two previous ovrloaded FindObjectAt methods, with a new one that is more useful and flexible.
  • Improved painting mechanism to increase speed and reduce cpu usage.
  • Fixed a bug in moving a group of selected link objects.
  • Fixed a bug in inserting links that happening in Delphi 4 and 5.
  • Fixed the bug about not triggering OnObjectUnhook event when unhooking was consequence of an object deletion.
  • Fixed a bug in saving BackgroundMargins.
  • Fixed a bug in MinimizeText routine. In addition, this routine improved to instead of three periods as ellipsis (...), when selected font supports, uses single character ellipses (…).
  • Fixed a bug regarding positioning of the links.
  • Fixed some minor bugs.
  • And, many other improvements in the code.

• Version 2.00 (February 23, 2006)
  To improve performance and functionality of the control, most part of the code is written again. Because of that, if you are using your own modified version of the control, or if you have derived your own graph object, you may need to rewrite your code. Otherwise, you may need to do some small changes. The old saved graph files are backward compatible with the new version.

  Here are list of changes. General compatibility issues are markded as red.

• Changes in TSimpleGraph class are:
  • Added LockLinks property.
  • Added OnObjectBeginDrag and OnObjectEndDrag events.
  • Added OnObjectHook and OnObjectUnhook events.
  • Added OnCanHookLink event.
  • Replaced OnCanLinkNodes event with OnCanLinkObjects event.
  • Replaced ToggleNodesAt method with ToggleSelection method, which is more felexible. In addition, the new method precisely detects objects that are inside the selection rectangle or intersects it.
  • Added an overload for FindObjectAt method.
  • Altered Bounds parameter of InsertNode method from PRect to TRect.
  • Replaced LinkNodes method with InsertLink method, which has three other overloads.
  • Added ClearSelection method.
  • Renamed cmLinkNodes to cmInsertLink (See CommandMode property).
  • Removed IsValidLink method. Use CanLink method of TGraphLink as replacement.
  • Altered some keyboard and mouse actions. Besides that, each object has its own keyboard and mouse events.
  • Added missing code for checking graph contraints while moving/resizing objects using keyboard.
• Changes in TGraphObject class are:
  • Added Options property.
  • Added Dragging property as read-only.
  • Added BeginDrag, DragTo, and EndDrag methods.
  • Added HitTest method.
  • Added ContainsRect method.
  • Added Delete method.
  • Added IsLocked method.
  • Altered IsLink property to class method.
• Changes in TGraphLink are:
  • Improved functionality. The new links can have breakpoints, each endpoint optionally can be hooked to a graph object (node and link objects), and style of each endpoint is customizable.
  • Added Points, PointCount and Polyline properties.
  • Added TextPosition and TextSpacing properties.
  • Added LinkOptions property.
  • Replaced Kind property with BeginStyle and EndStyle properties.
  • Replaced ArrowSize property with BeginSize and EndSize properties.
  • Replace FromNode and ToNode properties with Source and Target properties.
  • Added CanMove method.
  • Added AddPoint, InsertPoint, RemovePoint, IndexOfPoint, AddBreakPoint, and NormalizeBreakpoints methods to manage link's polyline.
  • Added IsFixedPoint, IsHookedPoint, HookedObjectOf, HookedIndexOf, and HookedPointCount to query about points.
  • Added CanHook, Hook, Unhook, CanLink, and Link methods to manage hooking and linking actions.
  • Added Rotate and Scale methods.
• Changes in TGraphNode class are:
  • Added NodeOptions property.
  • Added BackgroundMargins property.
  • Added CanMoveResize method.
  • Removed QueryLinkTo method.
• Fixed clipped text problem that was occurring when graph was zoomed in.
• Added Vertices property to TPolygonalNode class as read-only.
• Altered base class of TRectangularNode from TGraphNode to TPolygonalNode.
• Added THexagonalNode class.
• Changes in TGraphConstraints class are:
  • Added WithinBounds method.
  • Added ConfineOffset method.
  • Altered prototype of ConfinePt and ConfineRect methods.
  • Fixed malfunction of ConfineRect method.
• Changes in Global Procedures are:
  • Added NormalizeAngle, EqualPoint, ScalePoints, ShiftPoints, MakeSquare, LineLength, NearestPointOnLine, and IntersectLinePolyline functions.
  • Altered prototype of IntersectLineRect, IntersectLineEllipse, IntersectLineRoundRect, and IntersectLinePolygon functions, so that they can calculate the intersection points of a general line. Before they could only calculate the intersection points of lines where passing thru the center of shape.
  • Altered return type of DistanceToLine function from integer to double.
  • Altered type of DistanceFromThisPt parameter of NextPointOfLine function from integer to double.
    
    
• Version 1.67 (November 14, 2005)
  • Added OnZoomChange event.
  • Bug on calling OnResize and OnCanResize events fixed.
    
    
• Version 1.66 (November 11, 2005)
  • Added property FixedScrollBars.
  • Applied GraphConstraints verification during insertion of a new node using mouse.
  • Added ConfinePt and ConfineRect methods to TGraphConstraints.
    
    
• Version 1.65 (November 10, 2005)
  • Added missing events OnClick and OnObjectClick.
  • Removed FreezeTopLeft property, and instead of that, to have more control on bounding rectangle of the graph, the new property GraphConstraints added.
  • The control's paint handler improved. So that, there is no memory limit on graph's bounds. In addition, the paint handler draws objects much faster than before.
  • The control accepts child controls.
    
    
• Version 1.61 (November 1, 2005)
  • Added event OnInfoTip to TSimpleGraph.
  • Added global procedure NearestPoint.
  • Changed all Extended data types to Double to prevent exception (Invalid Floating Point Operation).
  • Fixed the bug regarding to calculating the end points of the links (all the related routins are changed).
  • The limit on defining vertices for the polygon in TPolygonalNode class was removed.
    
    
• Version 1.60 (October 29, 2005)
  • Added property Layout to TGraphNode.
  • Added property DrawOrder to TSimpleGraph.
  • Added events OnBeforeDraw, OnAfterDraw, OnObjectBeforeDraw, and OnObjectAfterDraw to TSimpleGraph.
  • Added global procedures WrapText and MinimizeText.
  • If text of the object doesn't fit on the screen, the complete text can appear as tool tip (ShowHintproperty should be True).
  • The malfunction in drawing text of the nodes with the zoom factor other than 100% is fixed.
    Some minor tweaks.
    
    
• Version 1.58 (September 29, 2005)
  • The Hint property added to TGraphObject.
    
    
• Version 1.57 (May 13, 2005)
  • Workaround to a Windows bug added (see here for details).
    
    
• Version 1.56 (May 9, 2005)
  • Copy/Paste bug fixed.
    
    
• Version 1.55 (April 21, 2005)
  • Memory leak bug fixed.
    
    
• Version 1.54.2 (August 24, 2004)
  • The black border that was appearing during scroll is fixed.
    
    
• Version 1.54.1 (August 20, 2004)
  • The bug in calculating the scroll bars' range fixed.
    
    
• Version 1.54 (August 6, 2004)
  • The new property MinNodeSize added to TSimpleGraph.
  • The new property ArrowSize added to TGraphLink.
  • Some minor tweaks.
    
    
• Version 1.53.1 (August 4, 2004)
  • The bug regarding to FreezeTopLeft property fixed.
    
    
• Version 1.53 (August 4, 2004)
  • The bug in moving/resizing overlapped objects fixed.
  • The new property FreezeTopLeft added to TSimpleGraph.
    
    
• Version 1.52 (July 18, 2004)
  • The scrolling malfunction when the zoom was greater than 100% is fixed.
    
    
• Version 1.51 (June 28, 2004)
  • A minor bug fixed.
    
    
• Version 1.50 (June 22, 2004)
  • VisibleBounds property added to TSimpleGraph.
• The new abstract class TPolygonalNode introduced.
• Triangular, Rhomboidal, and pentagonal nodes defined.
• Some new global functions added.
• Some speed improvements.
  
  
• Version 1.21.1 (June 18, 2004)
  • The compiler error on Delphi 4 fixed.
    
    
• Version 1.21 (June 13, 2004)
  • The new property SelectionBounds added.
  • The new methods ZoomRect, ZoomObject, ZoomSelection, and ZoomGraph added.
  • The missing method GraphToClient added.
  • Some minor tweaks.
    
    
• Version 1.20 (June 12, 2004)
  • Zooming ability, and consequently Zoom, ZoomMin, ZoomMax and ZoomStep properties added to the control.
  • The new ClientToGraph method added.
    
    
• Version 1.10 (May 16, 2004)
  • The new property Kind added to TGraphLink.
  • LinkTypeTo method of TGraphNode renamed to QueryLinkTo, and also the functionality improved.
    
    
• Version 1.09 (May 9, 2004)
  • Some bugs were fixed.
    
    
• Version 1.08 (May 10, 2003)
  • The division by zero exception raised in calculating the distance of a point from a line was fixed.
    
    
• Version 1.07 (April 27, 2003)
  • The new property Background added to TGraphNode.
    
    
• Version 1.06 (April 23, 2003)
  • The PaintTo method removed and instead of that two methods Print and SaveAsMetafile added to TSimpleGraph.
  • The new property HideSelection added to TSimpleGraph.
    
    
• Version 1.05 (April 21, 2003)
  • The new properties Alignment and Margin were added to TGraphNode.
    
    
• Version 1.04 (April 21, 2003)
  • Modified to publish on public domain.
    
    
• Version 1.03 (August 27, 2000)
  • The problem of finding the intersection of line and round rectangle was fixed.
    
    
• Version 1.02 (August 22, 2000)
  • The bug in movement of links was fixed.
    
    
• Version 1.01 (July 01, 2000)
  • The wrong behavior of the control when nodes are locked was fixed.
    
    
• Version 1.00 (June 11, 2000)
  • Initial release.

ACKNOWLEDGMENT

Special thanks to:

• Bill Miller
• Stefan Melis
• Pavel Vrecion
• Elias Lamela
• Fotis Kokkoras
• Sergisan
• P_G
• Adem
• Hans-Peter Wickern
  

LICENSE

TSimpleGraph component is freeware. You may copy component's files AS LONG AS YOU COPY ALL OF THEM. If you want to change the source code in order to improve the component's features, performance, etc. please send me the new source code so that I can have a look at it. The changed source code should contain descriptions what you have changed, and of course your name. The only thing you MAY NOT CHANGE is the ORIGINAL COPYRIGHT INFORMATION.

DISCLAIMER

TSimpleGraph component is provided "AS IS" without any warranty of any kind, either express or implied. The entire risk as to the quality and performance of the software is with you. The author is NOT liable for any DAMAGES resulting from the use and misuse of the component, especially he is NOT liable for DAMAGES that were caused BY ANY VERSION WHICH HAS NOT BEEN PROGRAMMED BY THE AUTHOR HIMSELF.