A question about 'Render DrawStyle' Sample error

MikeD

Hi!
I am running the "Render DrawStyle" sample and it throws me an error in line 156.

// Set the alpha for the image to a color mask

oImage.setAlphaFromMask( oImage.getColorMask( clrMask, true, 10 ) );

Script Error: Line 156

TypeError: Result of expression 'oImage.getColorMask' [undefined] is not a function.

I checked the Image object in the API and it has no 'setAlphaFromMask' nor a "getColorMask" methods! Image inherits from Qobject but it has not that methods either!

Are they methods of Image Object, and where can I find them as they are not refered to the API?