Remove the implication that XCanvas IS-A XBitmapCanvas, i.e. one can
access underlying pixels. That's a preparation for display-list based
canvas implementations, and was a rather silly assumption in the first
place.
Also fixes up all client sites.
Change-Id: I7a3d6f68ef46fe94b23cce7759cc0b8b6ca4dae9
2008/04/21 07:28:50 thb 1.8.26.4: RESYNC: (1.9-1.10); FILE MERGED
2007/12/20 22:18:59 thb 1.8.26.3: #i81092# #i78888# #i78925# #i79258# #i79437# #i84784# Large canvas rework, completing various areas such as color spaces, bitmap data access, true sprite and non-sprite implementations, and upstreaming the canvas parts of rodos emf+ rendering
2007/11/06 12:36:58 thb 1.8.26.2: RESYNC: (1.8-1.9); FILE MERGED
2007/10/01 13:02:03 thb 1.8.26.1: #i78888# #i78925# #i79258# #i79437# Merge from CWS picom
2006/02/02 11:37:39 thb 1.6.24.1: #i60699# Clarified docs; replaced flush call with sync on canvas output window, as now VCL internally does not sync anymore for blits
2005/10/20 13:55:22 thb 1.4.8.4: #i48939# Now correctly flushing the display queues in updateScreen(); removed unused code.
2005/10/08 12:55:07 thb 1.4.8.3: RESYNC: (1.4-1.5); FILE MERGED
2005/06/28 11:22:48 thb 1.4.8.2: #i48939# Removed refcounted reference to device in canvashelper (leads to circular references for SpriteCanvas); improved docs; added drawBezier() implementation
2005/06/17 23:49:50 thb 1.4.8.1: #i48939# Huge refactoring of canvas; as much functionality as possible is now common in a bunch of shared base classes (input checking, locking, sprite redraw, etc.); added scroll update optimization, transparently to all canvas implementations
2004/11/17 17:00:30 thb 1.1.2.4: #118514# Canvas module reorg
2004/10/11 00:00:06 thb 1.1.2.3: #i34997# Added new method XCanvas::drawBitmapModulated(), to facilitate global alpha channel changes when rendering bitmaps
2004/09/27 20:12:31 thb 1.1.2.2: #110496# Fixed problem with CanvasBitmap instances with alpha channel (simply ignored that before)
2004/07/20 19:22:23 thb 1.1.2.1: #110496# Removed self-references to various interface implementations, along the lines, factored out common base implementation for all c++ canvases
