Lingo Dictionary > A-C > createMatte()

 

createMatte()

Syntax

imageObject.createMatte({alphaThreshold})

Description

This function creates and returns a matte object that you can use with copyPixels() to duplicate the effect of the matte sprite ink. The matte object is created from the specified image object's alpha layer. The optional parameter alphaThreshold excludes from the matte all pixels whose alpha channel value is below that threshold. It is used only with 32-bit images that have an alpha channel. The alphaThreshold must be a value between 0 and 255.

Matte objects aren't image objects; they are useful only with the copyPixels() function. To save time, if you plan to use the same image as a matte more than once, it's best to create the matte and save it in a variable for reuse.

Example

This statement creates a new matte object from the alpha layer of the image object testImage and ignores pixels with alpha values below 50%:

newMatte = testImage.createMatte(128)

See also

copyPixels(), createMask()