grabpixmap and save with alpha

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Pete Rigz

I've been creating a little particle editor and I wanted to add a feature where you can save a animation strip of the effect with all alpha info etc. After searching the forums here for clues I got as far as saving it ok except it's just not quite right, like the image it's saving isn't as opaque as it should be. The below code demonstrates the problem:

SetGraphicsDriver GLMax2DDriver() 

Graphics (1000, 500,,, GRAPHICS_ALPHABUFFER) 
SetClsColor2 0, 0, 0, 0
Cls

SetBlend ALPHABLEND
SetAlpha.5
SetColor 255, 0, 0
For Local c:Int = 1 To 255
	Local size:Int = Rnd(50, 125) 
	SetColor c, 0, 0
	DrawOval Rnd(100, 300), Rnd(100, 300), size, size
Next
SetAlpha 1
SetColor 255, 255, 255
Local pixmap:TPixmap = GrabPixmap(0, 0, 500, 500) 
'SavePixmapPNG(pixmap, "test.png") 
Local testimg:TImage = LoadImage(pixmap) 
DrawImage testimg, 500, 0

Flip
WaitKey
 
Function SetClsColor2(red, green, blue, alpha = 255) 
	glClearColor red / 255.0, green / 255.0, blue / 255.0, alpha / 255.0
End Function

Basically that should draw a few ovals grab it as a pixmap then load that as an image and draw it to the right to compare. How it appears on the right is how it saves too and as you should see it's not grabbing the image properly somehow.

Hopefully it's something simple but any ideas would be greatly appreciated!