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 |
gboolean |
Whether to set a color to zero opacity. |
|
r |
guchar |
Red value to substitute. |
|
g |
guchar |
Green value to substitute. |
|
b |
guchar |
Blue value to substitute. |
Return value
Returns: | GdkPixbuf |
A newly-created pixbuf. |
|
The caller of the method takes ownership of the data, and is responsible for freeing it. |