Class DrawPane

All Implemented Interfaces:
HasAttachHandlers, HasHandlers, EventListener, HasVisibility, IsWidget, LogicalStructure, HasDrawEndHandlers, HasDrawStartHandlers, HasClearHandlers, HasClickHandlers, HasDoubleClickHandlers, HasDragMoveHandlers, HasDragRepositionMoveHandlers, HasDragRepositionStartHandlers, HasDragRepositionStopHandlers, HasDragResizeMoveHandlers, HasDragResizeStartHandlers, HasDragResizeStopHandlers, HasDragStartHandlers, HasDragStopHandlers, HasDropHandlers, HasDropMoveHandlers, HasDropOutHandlers, HasDropOverHandlers, HasFocusChangedHandlers, HasHoverHandlers, HasHoverHiddenHandlers, HasKeyDownHandlers, HasKeyPressHandlers, HasMouseDownHandlers, HasMouseMoveHandlers, HasMouseOutHandlers, HasMouseOverHandlers, HasMouseStillDownHandlers, HasMouseUpHandlers, HasMouseWheelHandlers, HasMovedHandlers, HasParentMovedHandlers, HasResizedHandlers, HasRightMouseDownHandlers, HasRuleContextChangedHandlers, HasScrolledHandlers, HasShowContextMenuHandlers, HasVisibilityChangedHandlers
Direct Known Subclasses:
FacetChart, Gauge

public class DrawPane extends Canvas implements HasDrawEndHandlers, HasDrawStartHandlers
A DrawPane is a container for drawing bitmap and vector graphics using browser's built-in freeform drawing capabilities. These include the HTML5 <canvas> tag and SVG (Scalable Vector Graphics) where available, and the VML (Vector Markup Language) for legacy browsers (Internet Explorer 8 and earlier).

To draw in a DrawPane you create DrawLines, DrawOvals, DrawPaths and other DrawItem-based components, and place them in the DrawPane via drawItems or add them incrementally via addDrawItem().

DrawItems support a variety of common features, such as gradient fills, arrowheads, events such as click() and built-in control knobs for end user resizing and manipulation of shapes.

Common shapes such as rectangles, ovals and triangles have dedicated DrawItem subclasses. For other shapes, consider:

  • DrawPath - a multi-segment line with straight segments, defined by a series of points
  • DrawPolygon - a closed shape with straight sides, defined by a series of points
  • DrawShape - a multi-segment line or closed shape whose sides can be defined by a series of commands, including curved arcs

NOTE:To use the Drawing subsystem, include the Drawing module in your application by including <inherits name="com.smartgwt.Drawing"/> in your GWT module XML.

Note on Coordinate Systems

There are three different coordinate systems involved when a DrawItem is drawn onto a DrawPane:

The view port of the DrawPane is the rectangle in the global coordinate system from (0, 0) that is as wide as the DrawPane's inner content width and as high as the DrawPane's inner content height. Note: In the case of a FacetChart showing a zoom chart, the view port height is decreased by the height of the zoom chart.

One other coordinate system in use by a DrawPane when drag-scrolling is enabled is the "viewbox coordinate system". The viewbox coordinate system is the drawing coordinate system with the translate and zoomLevel transforms applied.

  • Constructor Details

    • DrawPane

      public DrawPane()
    • DrawPane

      public DrawPane(JavaScriptObject jsObj)
  • Method Details

    • getOrCreateRef

      public static DrawPane getOrCreateRef(JavaScriptObject jsObj)
    • changeAutoChildDefaults

      public static void changeAutoChildDefaults(String autoChildName, Canvas defaults)
      Changes the defaults for Canvas AutoChildren named autoChildName.
      Parameters:
      autoChildName - name of an AutoChild to customize the defaults for.
      defaults - Canvas defaults to apply. These defaults override any existing properties without destroying or wiping out non-overridden properties. For usage tips on this param, see SGWTProperties.
      See Also:
    • changeAutoChildDefaults

      public static void changeAutoChildDefaults(String autoChildName, FormItem defaults)
      Changes the defaults for FormItem AutoChildren named autoChildName.
      Parameters:
      autoChildName - name of an AutoChild to customize the defaults for.
      defaults - FormItem defaults to apply. These defaults override any existing properties without destroying or wiping out non-overridden properties. For usage tips on this param, see SGWTProperties.
      See Also:
    • create

      protected JavaScriptObject create()
      Overrides:
      create in class Canvas
    • setCanDragScroll

      public DrawPane setCanDragScroll(boolean canDragScroll) throws IllegalStateException
      Can the user drag-scroll the DrawPane?
      Overrides:
      setCanDragScroll in class Canvas
      Parameters:
      canDragScroll - New canDragScroll value. Default value is false
      Returns:
      DrawPane instance, for chaining setter calls
      Throws:
      IllegalStateException - this property cannot be changed after the component has been created
      See Also:
    • getCanDragScroll

      public boolean getCanDragScroll()
      Can the user drag-scroll the DrawPane?
      Overrides:
      getCanDragScroll in class Canvas
      Returns:
      Current canDragScroll value. Default value is false
      See Also:
    • setDrawingHeight

      public DrawPane setDrawingHeight(int drawingHeight) throws IllegalStateException
      When canDragScroll is enabled, this is the height of the area in viewbox coordinates that can be accessed through drag-scrolling.
      Parameters:
      drawingHeight - New drawingHeight value. Default value is 1000
      Returns:
      DrawPane instance, for chaining setter calls
      Throws:
      IllegalStateException - this property cannot be changed after the component has been created
    • getDrawingHeight

      public int getDrawingHeight()
      When canDragScroll is enabled, this is the height of the area in viewbox coordinates that can be accessed through drag-scrolling.
      Returns:
      Current drawingHeight value. Default value is 1000
    • setDrawingType

      public DrawPane setDrawingType(DrawingType drawingType) throws IllegalStateException
      Which type of drawing back-end should be used by this DrawPane? A default drawing back-end is automatically selected based on the browser.

      The drawingType can only be set to a drawing back-end type that is supported by the browser. It is provided for cases where the browser supports more than one drawing back-end. See the DrawingType documentation for the supported drawing back-ends and the list of browsers that support each type of drawing back-end.

      Note : This is an advanced setting

      Parameters:
      drawingType - New drawingType value. Default value is based on browser
      Returns:
      DrawPane instance, for chaining setter calls
      Throws:
      IllegalStateException - this property cannot be changed after the component has been created
    • getDrawingType

      public DrawingType getDrawingType()
      Which type of drawing back-end should be used by this DrawPane? A default drawing back-end is automatically selected based on the browser.

      The drawingType can only be set to a drawing back-end type that is supported by the browser. It is provided for cases where the browser supports more than one drawing back-end. See the DrawingType documentation for the supported drawing back-ends and the list of browsers that support each type of drawing back-end.

      Returns:
      Current drawingType value. Default value is based on browser
    • setDrawingWidth

      public DrawPane setDrawingWidth(int drawingWidth) throws IllegalStateException
      When canDragScroll is enabled, this is the width of the area in viewbox coordinates that can be accessed through drag-scrolling.
      Parameters:
      drawingWidth - New drawingWidth value. Default value is 1000
      Returns:
      DrawPane instance, for chaining setter calls
      Throws:
      IllegalStateException - this property cannot be changed after the component has been created
    • getDrawingWidth

      public int getDrawingWidth()
      When canDragScroll is enabled, this is the width of the area in viewbox coordinates that can be accessed through drag-scrolling.
      Returns:
      Current drawingWidth value. Default value is 1000
    • setDrawItems

      public DrawPane setDrawItems(DrawItem... drawItems) throws IllegalStateException
      Array of DrawItems to initially display in this DrawPane.
      Parameters:
      drawItems - New drawItems value. Default value is null
      Returns:
      DrawPane instance, for chaining setter calls
      Throws:
      IllegalStateException - this property cannot be changed after the component has been created
    • getDrawItems

      public DrawItem[] getDrawItems()
      Array of DrawItems to initially display in this DrawPane.
      Returns:
      Current drawItems value. Default value is null
    • setEditProxyConstructor

      public DrawPane setEditProxyConstructor(String editProxyConstructor) throws IllegalStateException
      Default class used to construct the EditProxy for this component when the component is first placed into edit mode.
      Overrides:
      setEditProxyConstructor in class Canvas
      Parameters:
      editProxyConstructor - New editProxyConstructor value. Default value is "DrawPaneEditProxy"
      Returns:
      DrawPane instance, for chaining setter calls
      Throws:
      IllegalStateException - this property cannot be changed after the component has been created
      See Also:
    • getEditProxyConstructor

      public String getEditProxyConstructor()
      Default class used to construct the EditProxy for this component when the component is first placed into edit mode.
      Overrides:
      getEditProxyConstructor in class Canvas
      Returns:
      Current editProxyConstructor value. Default value is "DrawPaneEditProxy"
      See Also:
    • setGradients

      public DrawPane setGradients(Gradient... gradients) throws IllegalStateException
      Array of gradients that can be referenced by DrawItems placed on this DrawPane. Each gradient must have an ID assigned to be used for reference.
      Parameters:
      gradients - New gradients value. Default value is null
      Returns:
      DrawPane instance, for chaining setter calls
      Throws:
      IllegalStateException - this property cannot be changed after the component has been created
    • getGradients

      public Gradient[] getGradients()
      Array of gradients that can be referenced by DrawItems placed on this DrawPane. Each gradient must have an ID assigned to be used for reference.
      Returns:
      Current gradients value. Default value is null
    • setRotation

      public DrawPane setRotation(float rotation)
      Deprecated.
      Rotation in degrees for the DrawPane as a whole about the center of the DrawPane. The positive direction corresponds to clockwise rotation (for example, 45 is rotation clockwise by 45 degrees and -10 is rotation counterclockwise by 10 degrees).

      If this method is called after the component has been drawn/initialized: Sets the rotation of the DrawPane.
      Parameters:
      rotation - the new rotation in degrees. The positive direction corresponds to clockwise rotation. Default value is 0
      Returns:
      DrawPane instance, for chaining setter calls
    • getRotation

      public float getRotation()
      Deprecated.
      Rotation in degrees for the DrawPane as a whole about the center of the DrawPane. The positive direction corresponds to clockwise rotation (for example, 45 is rotation clockwise by 45 degrees and -10 is rotation counterclockwise by 10 degrees).
      Returns:
      Current rotation value. Default value is 0
    • setRotation

      public DrawPane setRotation(double rotation)
      Rotation in degrees for the DrawPane as a whole about the center of the DrawPane. The positive direction corresponds to clockwise rotation (for example, 45 is rotation clockwise by 45 degrees and -10 is rotation counterclockwise by 10 degrees).

      If this method is called after the component has been drawn/initialized: Sets the rotation of the DrawPane.
      Parameters:
      rotation - the new rotation in degrees. The positive direction corresponds to clockwise rotation. Default value is 0
      Returns:
      DrawPane instance, for chaining setter calls
    • getRotationAsDouble

      public double getRotationAsDouble()
      Rotation in degrees for the DrawPane as a whole about the center of the DrawPane. The positive direction corresponds to clockwise rotation (for example, 45 is rotation clockwise by 45 degrees and -10 is rotation counterclockwise by 10 degrees).
      Returns:
      Current rotation value. Default value is 0
    • setTranslate

      public DrawPane setTranslate(int[] translate) throws IllegalStateException
      Global translation. This array has two numbers. The first number is the X translation amount in pixels and the second number is the Y translation amount in pixels.
      Parameters:
      translate - New translate value. Default value is null
      Returns:
      DrawPane instance, for chaining setter calls
      Throws:
      IllegalStateException - this property cannot be changed after the component has been created
    • getTranslate

      public int[] getTranslate()
      Global translation. This array has two numbers. The first number is the X translation amount in pixels and the second number is the Y translation amount in pixels.
      Returns:
      Current translate value. Default value is null
    • setZoomLevel

      public DrawPane setZoomLevel(float zoomLevel)
      Deprecated.
      Zoom for the DrawPane as a whole, where 1 is normal size.

      If this method is called after the component has been drawn/initialized: Sets the zoom on this DrawPane to the specified magnification, maintaining the current viewport position.
      Parameters:
      zoomLevel - Desired zoom level as a float where 1.0 is equivalent to 100% magnification. Must be greater than 0. Default value is 1
      Returns:
      DrawPane instance, for chaining setter calls
    • getZoomLevel

      public float getZoomLevel()
      Deprecated.
      Zoom for the DrawPane as a whole, where 1 is normal size.
      Returns:
      Current zoomLevel value. Default value is 1
    • setZoomLevel

      public DrawPane setZoomLevel(double zoomLevel)
      Zoom for the DrawPane as a whole, where 1 is normal size.

      If this method is called after the component has been drawn/initialized: Sets the zoom on this DrawPane to the specified magnification, maintaining the current viewport position.
      Parameters:
      zoomLevel - Desired zoom level as a float where 1.0 is equivalent to 100% magnification. Must be greater than 0. Default value is 1
      Returns:
      DrawPane instance, for chaining setter calls
    • getZoomLevelAsDouble

      public double getZoomLevelAsDouble()
      Zoom for the DrawPane as a whole, where 1 is normal size.
      Returns:
      Current zoomLevel value. Default value is 1
    • addDrawItem

      public void addDrawItem(DrawItem item, boolean autoDraw)
      Adds a draw item to this DrawPane. If already added to a DrawPane, the draw item is removed from its current DrawPane and added to this DrawPane.

      NOTE: For performance reasons, this DrawPane may draw the new item on a delay to allow multiple items to be added and drawn at one time. The refreshNow() API will force the item to be drawn immediately.

      Parameters:
      item - item to add.
      autoDraw - If explicitly set to false, and this drawPane is drawn, don't draw the newly added item
    • addGradient

      public String addGradient(Gradient gradient)
      Add a new gradient to the drawPane shared gradient list (gradients). If the gradient does not have an ID a new one will be assigned.
      Parameters:
      gradient - gradient to add
      Returns:
      the ID of the gradient (either provided or auto-assigned). See Identifier
    • createLinearGradient

      public String createLinearGradient(String id, LinearGradient linearGradient)
      Deprecated.
      in favor of addGradient()
      Creates a linear gradient which can be used by any DrawItem of this DrawPane. Any DrawItem's fillGradient can reference the gradient by the given ID.
      Parameters:
      id - the ID of the linear gradient. See Identifier
      linearGradient - the linear gradient
      Returns:
      id. See Identifier
    • createRadialGradient

      public String createRadialGradient(String id, RadialGradient radialGradient)
      Deprecated.
      in favor of addGradient()
      Creates a radial gradient which can be used by any DrawItem of this DrawPane. Any DrawItem's fillGradient can reference the gradient by the given ID.
      Parameters:
      id - the ID of the radial gradient. See Identifier
      radialGradient - the radial gradient
      Returns:
      id. See Identifier
    • createSimpleGradient

      public String createSimpleGradient(String id, SimpleGradient simple)
      Deprecated.
      in favor of addGradient()
      Creates a simple linear gradient which can be used by any DrawItem of this DrawPane. Any DrawItem's fillGradient can reference the gradient by the given ID.
      Parameters:
      id - the ID of the simple linear gradient. See Identifier
      simple - the simple linear gradient
      Returns:
      id. See Identifier
    • destroyItems

      public void destroyItems()
      Permanently destroy all DrawItems currently associated with this DrawPane, leaving the DrawPane itself intact
    • addDrawEndHandler

      public HandlerRegistration addDrawEndHandler(DrawEndHandler handler)
      Add a drawEnd handler.

      Called after we finish drawing to the underlying HTML5 <canvas> element of a DrawPane, after the last DrawItem has been drawn. Only called if the DrawingType is DrawingType.BITMAP.

      Specified by:
      addDrawEndHandler in interface HasDrawEndHandlers
      Parameters:
      handler - the drawEnd handler
      Returns:
      HandlerRegistration used to remove this handler
    • addDrawStartHandler

      public HandlerRegistration addDrawStartHandler(DrawStartHandler handler)
      Add a drawStart handler.

      Called when we start drawing to the underlying HTML5 <canvas> element of a DrawPane, right after the element is cleared. Only called if the DrawingType is DrawingType.BITMAP.

      Specified by:
      addDrawStartHandler in interface HasDrawStartHandlers
      Parameters:
      handler - the drawStart handler
      Returns:
      HandlerRegistration used to remove this handler
    • erase

      public void erase()
      Call DrawItem.erase() on all DrawItems currently associated with the DrawPane.

      The DrawItems will continue to exist, and you can call draw() on them to make them appear again, or destroy to get rid of them permanetly. Use destroyItems() to permanently get rid of all DrawItems.

    • getDataURL

      public String getDataURL()
      Get a "data:" URL encoding the current contents of the DrawPane.

      The returned "data:" URLs can be used anywhere a URL to an image is valid, for example, Img.src.

      This method will directly return the data URL on modern browsers when using <canvas>-style rendering (the default), and if there are no DrawImages in this DrawPane that load cross-domain images.

      On legacy browers (any version of IE in "quirks" mode, all versions of IE prior to 9.0), or if there is a DrawImage that loads a cross-domain image, data URL generation requires a server trip and requires the Smart GWT Server to be installed with the same set of required .jars as are required for PDF export of charts in legacy IE. The method will return null and a callback must be passed, which fires when the data URL has been retrieved from the server.

      If the callback is passed but no server trip is required, the callback is fired immediately.

      For obtaining PNG or other image data for use in server-side processing (such as attaching to automated emails or saving to a database), see also the server-side APIs in com.isomorphic.contentexport.ImageExport.

      Note: It is recommended to pass a callback instead of relying on the method returning the data URL directly. This is because the callback will always be called with the generated data URL, whereas work-arounds for browser bugs may require asynchronous generation of the data URL, meaning that a data URL might not be returned immediately in certain browsers for certain DrawPane contents.

      Returns:
      the data URL if synchronously generated.
      See Also:
    • getDataURL

      public String getDataURL(DataURLCallback callback)
      See Also:
    • getDataURL

      public String getDataURL(DataURLCallback callback, DataURLFormat format)
      Get a "data:" URL encoding the current contents of the DrawPane.

      The returned "data:" URLs can be used anywhere a URL to an image is valid, for example, Img.src.

      This method will directly return the data URL on modern browsers when using <canvas>-style rendering (the default), and if there are no DrawImages in this DrawPane that load cross-domain images.

      On legacy browers (any version of IE in "quirks" mode, all versions of IE prior to 9.0), or if there is a DrawImage that loads a cross-domain image, data URL generation requires a server trip and requires the Smart GWT Server to be installed with the same set of required .jars as are required for PDF export of charts in legacy IE. The method will return null and a callback must be passed, which fires when the data URL has been retrieved from the server.

      If the callback is passed but no server trip is required, the callback is fired immediately.

      For obtaining PNG or other image data for use in server-side processing (such as attaching to automated emails or saving to a database), see also the server-side APIs in com.isomorphic.contentexport.ImageExport.

      Note: It is recommended to pass a callback instead of relying on the method returning the data URL directly. This is because the callback will always be called with the generated data URL, whereas work-arounds for browser bugs may require asynchronous generation of the data URL, meaning that a data URL might not be returned immediately in certain browsers for certain DrawPane contents.

      Parameters:
      callback - callback to fire when the data URL is available. The callback is called regardless of whether the data URL is also returned.
      format - the format of the data URL. If not specified, then com.smartgwt.client.types.DataURLFormat#ALL is assumed.
      Returns:
      the data URL if synchronously generated.
      See Also:
    • getDrawingPoint

      public Point getDrawingPoint()
      Returns the point of the last event in the drawing coordinate system.

      To give a concrete example, suppose that this DrawPane has zoomLevel 2 and drag-panning is not enabled (just to simplify this example). If getOffsetX() and getOffsetY() is (0, 0) (i.e. the mouse pointer is located at the top left point of this DrawPane), then getDrawingPoint() would return (0, 0). If getOffsetX/Y() is (20, 40), then getDrawingPoint() would return (10, 20) because when the 2× zoom level is applied, (10, 20) is translated to (20, 40) on the screen. You could, for example, create a new DrawLine with startPoint (10, 20) and when this line is drawn on screen, the position of the line's start point would be at offset (20, 40) on screen.

      Returns:
      the point in drawing coordinates of the last event.
    • getDrawingX

      public int getDrawingX()
      Returns the X coordinate in the drawing coordinate system of the last event. Note: If you need both the X and Y coordinates in the drawing coordinate system of the last event, it is more efficient to call getDrawingPoint() instead.

      See the documentation of getDrawingPoint() for a clarifying example.

      Returns:
      X coordinate in the drawing coordinate system of the last event.
    • getDrawingY

      public int getDrawingY()
      Returns the Y coordinate in the drawing coordinate system of the last event. Note: If you need both the X and Y coordinates in the drawing coordinate system of the last event, it is more efficient to call getDrawingPoint() instead.

      See the documentation of getDrawingPoint() for a clarifying example.

      Returns:
      Y coordinate in the drawing coordinate system of the last event.
    • getGradient

      public Gradient getGradient(String gradientID)
      Returns gradient for gradientID.
      Parameters:
      gradientID - ID of gradient to retrieve. See Identifier
      Returns:
      the gradient or null if not found
      See Also:
    • getSvgString

      public String getSvgString()
      Converts this DrawPane to the source of an <svg> element equivalent to the current drawing.

      In Pro edition and above, the returned string can be used with RPCManager.exportImage() to download an image, or with server-side APIs in com.isomorphic.contentexport.ImageExport to obtain various kinds of images for further server-side processing.

      Returns:
      the source of an <svg> element.
      See Also:
    • refreshNow

      public void refreshNow()
      Immediately draws or redraws any items of this DrawPane that are scheduled to be drawn or redrawn after a delay.

      For performance reasons, this DrawPane may delay refreshing its display to allow for multiple draw item updates to be drawn at the same time. If this is occurring, refreshNow() will immediately refresh the display instead of refreshing the display in a timer.

    • removeGradient

      public void removeGradient(String gradientID)
      Removes gradient for gradientID.
      Parameters:
      gradientID - ID of gradient to remove. See Identifier
      See Also:
    • rotate

      public void rotate(double degrees)
      Synonym of setRotation().
      Parameters:
      degrees - the new rotation in degrees. The positive direction corresponds to clockwise rotation.
    • zoom

      public void zoom(float zoomLevel)
      Deprecated.
      Synonym of setZoomLevel().
      Parameters:
      zoomLevel - Desired zoom level as a float where 1.0 is equivalent to 100% magnification. Must be greater than 0.
    • zoom

      public void zoom(double zoomLevel)
      Synonym of setZoomLevel().
      Parameters:
      zoomLevel - Desired zoom level as a float where 1.0 is equivalent to 100% magnification. Must be greater than 0.
    • bezier

      public static double bezier(double p1, double cp1, double cp2, double p2, double t)
      Computes a cubic Bézier curve polynomial: B(t) = (1 - t)3P1 + 3(1 - t)2tCP1 + 3(1 - t)t2CP2 + t3P2
      Parameters:
      p1 - starting point coordinate
      cp1 - first control point coordinate
      cp2 - second control point coordinate
      p2 - end point coordinate
      t - the value of the parameter of the curve, between 0 and 1
      Returns:
      the value of the polynomial B(t) at t
    • bezierExtrema

      public static double[] bezierExtrema(double p1, double cp1, double cp2, double p2)
      Computes the minimum and maximum value of the cubic Bézier curve polynomial defined in bezier(), for 0 ≤ t ≤ 1.
      Parameters:
      p1 - starting point coordinate
      cp1 - first control point coordinate
      cp2 - second control point coordinate
      p2 - end point coordinate
      Returns:
      the minimum and maximum value of the cubic Bézier curve polynomial
    • getBezierBoundingBox

      public static double[] getBezierBoundingBox(Point p1, Point cp1, Point cp2, Point p2)
      Calculate the bounding box of the cubic Bézier curve with endpoints p1 and p2 and control points cp1 and cp2.
      Parameters:
      p1 - start point of the curve
      cp1 - first cubic Bézier control point
      cp2 - second cubic Bézier control point
      p2 - end point of the curve
      Returns:
      the x1, y1, x2, y2 coordinates. The point (x1, y1) is the top-left point of the bounding box and the point (x2, y2) is the bottom-right point of the bounding box.
    • getPolygonPoints

      public static Point[] getPolygonPoints(int width, int height, int xc, int yc, double[] angles)
      Computes an array of Points for a polygon that has an equal distance from its center to any of its vertices and that fits in the given width and height.
      Parameters:
      width - width of target space
      height - height of target space
      xc - center point x
      yc - center point y
      angles - the complete list of angles (in radians) with respect to the center point at which the polygon must have vertices
      Returns:
      list of the vertices of the polygon
    • getRegularPolygonPoints

      public static Point[] getRegularPolygonPoints(int n, int width, int height, int xc, int yc, double startAngle)
      Calls getPolygonPoints() with angles spread evenly over the full 360 degrees.
      Parameters:
      n - the number of vertices the polygon
      width - width of target space
      height - height of target space
      xc - center point x
      yc - center point y
      startAngle - the angle (in radians) with respect to the center point of the first vertex of the polygon
      Returns:
      list of the vertices of the regular polygon
    • scaleAndCenter

      public static void scaleAndCenter(int width, int height, int xc, int yc, Point... points)
      Computes the top-, left-, bottom-, and right-most coordinates in a list of points, then translates and scales all points to fit the entire shape into the given width and height.
      Parameters:
      width - width of target space
      height - height of target space
      xc - center point x
      yc - center point y
      points - list of points to scale and translate
    • scaleAndCenterBezier

      public static void scaleAndCenterBezier(int width, int height, int xc, int yc, Point startPoint, Point endPoint, Point controlPoint1, Point controlPoint2)
      Computes the top-, left-, bottom-, and right-most coordinates containing the Bézier curve defined by startPoint, controlPoint1, controlPoint2, and endPoint, then translates and scales these four points to fit the entire curve into the given width and height.
      Parameters:
      width - width of target space
      height - height of target space
      xc - center point x
      yc - center point y
      startPoint - start point of the curve
      endPoint - end point of the curve
      controlPoint1 - first cubic Bézier control point
      controlPoint2 - second cubic Bézier control point
    • setDefaultProperties

      public static void setDefaultProperties(DrawPane drawPaneProperties)
      Class level method to set the default properties of this class. If set, then all existing and subsequently created instances of this class will automatically have default properties corresponding to the properties set on the SmartGWT class instance passed to this function before its underlying SmartClient JS object was created. This is a powerful feature that eliminates the need for users to create a separate hierarchy of subclasses that only alter the default properties of this class. Can also be used for skinning / styling purposes.

      Note: This method is intended for setting default attributes only and will affect all instances of the underlying class (including those automatically generated in JavaScript). This method should not be used to apply standard EventHandlers or override methods for a class - use a custom subclass instead. Calling this method after instances have been created can result in undefined behavior, since it bypasses any setters and a class instance may have already examined a particular property and not be expecting any changes through this route.

      Parameters:
      drawPaneProperties - properties that should be used as new defaults when instances of this class are created
      See Also:
    • setAutoChildProperties

      public void setAutoChildProperties(String autoChildName, DrawItem properties) throws IllegalStateException
      Sets the properties for creating a DrawItem AutoChild named autoChildName.

      properties must not have already been created (properties.isCreated() must be false).

      NOTE: Overrides at override points are not applied to the AutoChild created from properties; that is, if the Java Class of properties overrides a Smart GWT override point, the custom method implementation will not be called.

      Throws:
      IllegalStateException - if properties has been created.
      See Also:
    • getPrintHTML

      public String getPrintHTML(PrintProperties printProperties, PrintHTMLCallback callback)
      Retrieves printable HTML for this component and all printable subcomponents.

      By default any Canvas with children will simply collect the printable HTML of its children by calling getPrintHTML() on each child that is considered printable.

      If overriding this method for a custom component, you should either return a String of printable HTML string directly or return null, and fire the callback (if provided).

      To return an empty print representation, return an empty string ("") rather than null.

      The printProperties argument, if passed, must be passed to any subcomponents on which getPrintHTML() is called.

      Notes on printing

      To print a DrawPane for export on IE8 and earlier, it is PrintProperties with printForExport:true:

       final PrintProperties pp = new PrintProperties();
       pp.setPrintForExport(true);
       final String exportHTML = drawPane.getPrintHTML(pp, null);
       

      Note: this is an override point.

      Overrides:
      getPrintHTML in class Canvas
      Parameters:
      printProperties - properties to configure printing behavior - may be null.
      callback - optional callback to fire. Generated HTML should be passed to the PrintHTMLCallback.setHTML(String) method of the callback.
      Returns:
      null if the print HTML is being generated asynchronously and/or a callback is provided; otherwise, the direct print HTML for this component (but note that returning direct print HTML is a deprecated feature).
      See Also:
    • getUnderlyingGWTCanvas

      public Canvas getUnderlyingGWTCanvas()
      Returns the GWT Canvas underlying this DrawPane. Throws an DrawPane.InvalidDrawingTypeException if the DrawingType isn't a DrawingType.BITMAP.

      To create a DrawItem drawn by custom GWT Canvas drawing code, you should:

      Returns:
      the GWT Canvas
      See Also:
    • setLogicalStructure

      public LogicalStructureObject setLogicalStructure(DrawPaneLogicalStructure s)
      Setter implementing the LogicalStructure interface, which supports Eclipse's logical structure debugging facility.
    • getLogicalStructure

      public LogicalStructureObject getLogicalStructure()
      Getter implementing the LogicalStructure interface, which supports Eclipse's logical structure debugging facility.
      Specified by:
      getLogicalStructure in interface LogicalStructure
      Overrides:
      getLogicalStructure in class Canvas