Xojo Documentation Xojo Documentation

For desktop applications, see Canvas.

Class (inherits from WebControl)

New in 2012r2

WebCanvas controls are very useful for implementing your own graphical controls because you can use the WebGraphics class to draw inside the WebCanvas region.

Events

Close MouseDown Open ContextualMenuAction MouseEnter Paint DoubleClick MouseExit Resized DropObject MouseMove Shown Hidden MouseUp

Properties

ContextualMenu Left Parent ControlID LockBottom Style Cursor LockHorizontal Top DisableDiffEngine LockLeft VerticalCenter DragOverStyle LockRight Visible Enabled LockTop Width Height LockVertical Zindex HelpTag Name HorizontalCenter Page

Methods

AcceptPictureDrop AllowTextDrag PresentContextualMenu AcceptRawDataDrop Close Refresh AcceptTextDrop ExecuteJavaScript SetFocus AllowPictureDrag Invalidate ShowURL AllowRawDataDrag MsgBox Supported

Notes

Remember: Browsers maintain an uncompressed raster image of the contents of the canvas in memory so it can be displayed to the user. A 1024x1024 pixel canvas requires 4MB of RAM (4 bytes of color data per pixel). A browser may refuse a request to create a canvas that is too large. For instance iOS5 has a memory limit of 10MB for a single web page (it has been increased to 25MB in iOS6). On a Retina display, canvases require 4 times as much memory as a non-retina display.

See Also

WebGraphics, Graphics classes; UserGuide:Web Canvas topic