Displaying images with alpha

Hi!

AFAICT, it's not possible to display images with alpha data.

Is there something I've missed, or, if not, are there any plans for supporting displaying images with alphaData?

I can sort of hack around it by creating masks based on alphaData where alpha < threshold (which is read correctly from my png sources with colorType=6) in CgDeviceIndependentImage, 

by modifying:

transparencyMask
 "Answer the transparency mask or nil if there are no transparent pixels"
 alphaData isNil ifFalse: [^self alphaMaskImage].
 transparentPixel isNil ifTrue: [ ^ nil ].
 transparencyMask isNil ifFalse: [ ^ transparencyMask ].
 ^ transparencyMask := self colorMaskImage: transparentPixel

and implementing:

alphaMaskImage
 "Answer a new CgDeviceIndependentImage with the same width and
 height as the receiver, but depth one, with zero bits whereever
 alphaData is zero"


 | row w answer |
 row := (self depth > 8 ifTrue: [ Array ] ifFalse: [ ByteArray ]) new: (w := self width).
 answer := CgDeviceIndependentImage
 width: w
 height: self height
 depth: 1
 palette: (CgIndexedPalette grayRamp: 2).
 0 to: self height - 1 do: [ :y | |rowStart|
 rowStart := y * self width.
 
 1 to: w do: [ :i |
"Threshold; fully transparent, alpha 0"
 row at: i put: ((alphaData at: rowStart + i) = 0 ifTrue: [ 0 ] ifFalse: [ 1 ]) ].
 answer
 putPixels: 0
 y: y
 width: self width
 pixels: row
 startIndex: 1].
 ^ answer

But it would be nicer if this was/is available without having to modify core classes, and using true alpha instead of a mask-approximation :)

Cheers,

Henry