property NSColor : a reference to current application’s NSColor
property NSImage : a reference to current application’s NSImage
property NSZeroRect : a reference to current application’s NSZeroRect
property NSBezierPath : a reference to current application’s NSBezierPath
property NSCompositeCopy : a reference to current application’s NSCompositeCopy
property NSGraphicsContext : a reference to current application’s NSGraphicsContext
property NSBitmapImageRep : a reference to current application’s NSBitmapImageRep
property NSCalibratedRGBColorSpace : a reference to current application’s NSCalibratedRGBColorSpace

set {rCol, gCol, bCol} to choose color

set aNSImage to makeColoredNSImage({rCol, gCol, bCol}, 400, 400) of me
set aPath to generateCircle(200, 100, 100) of me

set bImage to my fillImage:aNSImage withTransparentPathFilling:aPath

set aFile to POSIX path of (choose file name)
set sRes to my saveNSImageAtPathAsPNG(bImage, aFile)

on fillImage:aSourceImg withTransparentPathFilling:aPath
　　set aSize to aSourceImg’s |size|()
　　set aWidth to (aSize’s width)
　　set aHeight to (aSize’s height)
　　
　　set aRep to NSBitmapImageRep’s alloc()’s initWithBitmapDataPlanes:(missing value) pixelsWide:aWidth pixelsHigh:aHeight bitsPerSample:8 samplesPerPixel:4 hasAlpha:true isPlanar:false colorSpaceName:(NSCalibratedRGBColorSpace) bytesPerRow:0 bitsPerPixel:0
　　
　　NSGraphicsContext’s saveGraphicsState()
　　
　　NSGraphicsContext’s setCurrentContext:(NSGraphicsContext’s graphicsContextWithBitmapImageRep:aRep)
　　
　　aSourceImg’s drawInRect:(current application’s NSMakeRect(0, 0, aWidth, aHeight)) fromRect:(NSZeroRect) operation:(NSCompositeCopy) fraction:(1.0)
　　
　　NSGraphicsContext’s currentContext()’s setCompositingOperation:(current application’s NSCompositeClear)
　　aPath’s fill()
　　
　　NSGraphicsContext’s restoreGraphicsState()
　　
　　set newImg to NSImage’s alloc()’s initWithSize:(aSize)
　　newImg’s addRepresentation:aRep
　　
　　return newImg
end fillImage:withTransparentPathFilling:

on generateCircle(theRadius, x, y)
　　set aRect to current application’s NSMakeRect(x, y, theRadius, theRadius)
　　set aCirCle to NSBezierPath’s bezierPath()
　　aCirCle’s appendBezierPathWithOvalInRect:aRect
　　return aCirCle
end generateCircle

on makeColoredNSImage(colList, aWidth, aHeight)
　　copy colList to {rCol, gCol, bCol}
　　set aColor to makeNSColorFromRGBA65535val(rCol, gCol, bCol, 1.0) of me
　　set aColoredImage to fillColorWithImage(aColor, aWidth, aHeight) of me
　　return aColoredImage
end makeColoredNSImage

on fillColorWithImage(aColor, aWidth, aHeight)
　　set colordImage to makeNSImageWithFilledWithColor(aWidth, aHeight, aColor, aWidth, aHeight) of me
　　colordImage’s lockFocus()
　　colordImage’s drawAtPoint:{0, 0} fromRect:(current application’s NSZeroRect) operation:(current application’s NSCompositeDestinationIn) fraction:1.0
　　colordImage’s unlockFocus()
　　return colordImage
end fillColorWithImage

on makeNSImageWithFilledWithColor(aWidth, aHeight, fillColor)
　　set anImage to NSImage’s alloc()’s initWithSize:(current application’s NSMakeSize(aWidth, aHeight))
　　anImage’s lockFocus()
　　—
　　set theRect to {{x:0, y:0}, {height:aHeight, width:aWidth}}
　　set theNSBezierPath to NSBezierPath’s bezierPath
　　theNSBezierPath’s appendBezierPathWithRect:theRect
　　—
　　fillColor’s |set|()
　　theNSBezierPath’s fill()
　　—
　　anImage’s unlockFocus()
　　—
　　return anImage
end makeNSImageWithFilledWithColor

on makeNSColorFromRGBA65535val(redValue as integer, greenValue as integer, blueValue as integer, alphaValue as integer)
　　set aRedCocoa to (redValue / 65535) as real
　　set aGreenCocoa to (greenValue / 65535) as real
　　set aBlueCocoa to (blueValue / 65535) as real
　　set aAlphaCocoa to 1.0 as real
　　set aColor to NSColor’s colorWithCalibratedRed:aRedCocoa green:aGreenCocoa blue:aBlueCocoa alpha:aAlphaCocoa
　　return aColor
end makeNSColorFromRGBA65535val

on saveNSImageAtPathAsPNG(anImage, outPath)
　　set imageRep to anImage’s TIFFRepresentation()
　　set aRawimg to current application’s NSBitmapImageRep’s imageRepWithData:imageRep
　　set pathString to current application’s NSString’s stringWithString:outPath
　　set newPath to pathString’s stringByExpandingTildeInPath()
　　set myNewImageData to (aRawimg’s representationUsingType:(current application’s NSPNGFileType) |properties|:(missing value))
　　set aRes to (myNewImageData’s writeToFile:newPath atomically:true) as boolean
　　return aRes
end saveNSImageAtPathAsPNG