Very often in image editing programs one needs to composite an image
(with or without an alpha channel) over a checkerboard pattern, to
indicate the transparency of the image. This method makes it
fairly easy to scale the image and composite it in such way:
<?php
GdkPixbuf composite_color_simple(int $dest_width,
int $dest_height,
GdkInterpType $interp_type,
int $overall_alpha,
int $check_size,
int $color1,
int $color2)
?>
The first 3 parameters are the same ones as for scale_simple(). The
rest are as follows:
$overall_alpha
an integer in the 0..255 range specifying the overall level of
transparency for the image.
$check_size
the size of the checks in the checkerboard pattern (has to be a power of 2).
$color1, $color2
the colors of the checks ('pixel' property of GdkColor)
