Matthew Fulmer uploaded a new version of Morphic to project The Trunk:
http://source.squeak.org/trunk/Morphic-mtf.501.mcz

==================== Summary ====================

Name: Morphic-mtf.501
Author: mtf
Time: 28 December 2010, 8:43:55.314 pm
UUID: 58aeefd2-fb62-1a45-aa60-92515490433b
Ancestors: Morphic-mtf.500

import from Croquet

Name: Morphic-ar.9
Author: ar
Time: 13 March 2006, 4:26:31 pm
UUID: 071f4e22-280e-1044-bf61-112022984c8c
Ancestors: Morphic-ar.8

- add a fix for transparent backgrounds in Morphic worlds

=============== Diff against Morphic-mtf.500 ===============

Item was changed:
  ----- Method: WorldState>>drawWorld:submorphs:invalidAreasOn: (in category 'update cycle') -----
  drawWorld: aWorld submorphs: submorphs invalidAreasOn: aCanvas 
  	"Redraw the damaged areas of the given canvas and clear the damage list. Return a collection of the areas that
  were redrawn."
  
  	| rectList n morphs rects validList |
  	rectList := damageRecorder invalidRectsFullBounds: aWorld viewBox.
  	"sort by areas to draw largest portions first"
  	rectList := rectList asArray sort: [:r1 :r2 | r1 area > r2 area].
  	damageRecorder reset.
  	n := submorphs size.
  	morphs := OrderedCollection new: n * 2.
  	rects := OrderedCollection new: n * 2.
  	validList := OrderedCollection new: n * 2.
+ 
+ 	"This is added in case we are drawing to a form that is to be used as a texture, and we want the background to be translucent."
+ 	aWorld color isTranslucent ifTrue:
+ 		[rectList do: [:r | aCanvas form fill: r fillColor: aWorld color]].
+ 
  	rectList do: 
  			[:dirtyRect | 
  			dirtyRect allAreasOutsideList: validList
  				do: 
  					[:r | | mm rectToFill remnants c rect i | 
  					"Experimental top-down drawing --
  			Traverses top to bottom, stopping if the entire area is filled.
  			If only a single rectangle remains, then continue with the reduced rectangle."
  
  					rectToFill := r.
  					i := 1.
  					[rectToFill isNil or: [i > n]] whileFalse: 
  							[mm := submorphs at: i.
  							((mm fullBounds intersects: r) and: [mm visible]) 
  								ifTrue: 
  									[morphs addLast: mm.
  									rects addLast: rectToFill.
  									remnants := mm areasRemainingToFill: rectToFill.
  									remnants size = 1 ifTrue: [rectToFill := remnants first].
  									remnants isEmpty ifTrue: [rectToFill := nil]].
  							i := i + 1].
  
  					"Now paint from bottom to top, but using the reduced rectangles."
  					rectToFill 
  						ifNotNil: [aWorld drawOn: (c := aCanvas copyClipRect: rectToFill)].
  					[morphs isEmpty] whileFalse: 
  							[(rect := rects removeLast) == rectToFill 
  								ifFalse: [c := aCanvas copyClipRect: (rectToFill := rect)].
  							c fullDrawMorph: morphs removeLast].
  					morphs reset.
  					rects reset.
  					validList add: r]].
  	^validList!