Pixbuf.addAlpha

gdkpixbuf.pixbuf.Pixbuf addAlpha(bool substituteColor, ubyte r, ubyte g, ubyte b)

Takes an existing pixbuf and adds an alpha channel to it.

If the existing pixbuf already had an alpha channel, the channel values are copied from the original; otherwise, the alpha channel is initialized to 255 (full opacity).

If substitute_color is TRUE, then the color specified by the (r, g, b) arguments will be assigned zero opacity. That is, if you pass (255, 255, 255) for the substitute color, all white pixels will become fully transparent.

If substitute_color is FALSE, then the (r, g, b) arguments will be ignored.

Parameters

`substituteColor`	Whether to set a color to zero opacity.
`r`	Red value to substitute.
`g`	Green value to substitute.
`b`	Blue value to substitute.

Returns

A newly-created pixbuf