Method
GdkPixbufPixbufadd_alpha
Declaration [src]
GdkPixbuf*
gdk_pixbuf_add_alpha (
const GdkPixbuf* pixbuf,
gboolean substitute_color,
guchar r,
guchar g,
guchar b
)
Description [src]
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
substitute_color-
Type:
gbooleanWhether to set a color to zero opacity.
r-
Type:
gucharRed value to substitute.
g-
Type:
gucharGreen value to substitute.
b-
Type:
gucharBlue value to substitute.
Return value
Type: GdkPixbuf
A newly-created pixbuf.
| The caller of the method takes ownership of the returned data, and is responsible for freeing it. |
The return value can be NULL. |