Top |
Functions
GdkPixbuf * | gdk_pixbuf_add_alpha () |
void | gdk_pixbuf_copy_area () |
void | gdk_pixbuf_saturate_and_pixelate () |
GdkPixbuf * | gdk_pixbuf_apply_embedded_orientation () |
void | gdk_pixbuf_fill () |
Description
These functions provide miscellaneous utilities for manipulating pixbufs. The pixel data in pixbufs may of course be manipulated directly by applications, but several common operations can be performed by these functions instead.
Functions
gdk_pixbuf_add_alpha ()
GdkPixbuf * gdk_pixbuf_add_alpha (const GdkPixbuf *pixbuf
,gboolean substitute_color
,guchar r
,guchar g
,guchar 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 (r
, g
, b
) will be
assigned zero opacity. That is, if you pass (255, 255, 255) for the
substitute color, all white pixels will become fully transparent.
Parameters
pixbuf |
A GdkPixbuf. |
|
substitute_color |
Whether to set a color to zero opacity. If this
is |
|
r |
Red value to substitute. |
|
g |
Green value to substitute. |
|
b |
Blue value to substitute. |
gdk_pixbuf_copy_area ()
void gdk_pixbuf_copy_area (const GdkPixbuf *src_pixbuf
,int src_x
,int src_y
,int width
,int height
,GdkPixbuf *dest_pixbuf
,int dest_x
,int dest_y
);
Copies a rectangular area from src_pixbuf
to dest_pixbuf
. Conversion of
pixbuf formats is done automatically.
If the source rectangle overlaps the destination rectangle on the same pixbuf, it will be overwritten during the copy operation. Therefore, you can not use this function to scroll a pixbuf.
Parameters
src_pixbuf |
Source pixbuf. |
|
src_x |
Source X coordinate within |
|
src_y |
Source Y coordinate within |
|
width |
Width of the area to copy. |
|
height |
Height of the area to copy. |
|
dest_pixbuf |
Destination pixbuf. |
|
dest_x |
X coordinate within |
|
dest_y |
Y coordinate within |
gdk_pixbuf_saturate_and_pixelate ()
void gdk_pixbuf_saturate_and_pixelate (const GdkPixbuf *src
,GdkPixbuf *dest
,gfloat saturation
,gboolean pixelate
);
Modifies saturation and optionally pixelates src
, placing the result in
dest
. src
and dest
may be the same pixbuf with no ill effects. If
saturation
is 1.0 then saturation is not changed. If it's less than 1.0,
saturation is reduced (the image turns toward grayscale); if greater than
1.0, saturation is increased (the image gets more vivid colors). If pixelate
is TRUE
, then pixels are faded in a checkerboard pattern to create a
pixelated image. src
and dest
must have the same image format, size, and
rowstride.
gdk_pixbuf_apply_embedded_orientation ()
GdkPixbuf *
gdk_pixbuf_apply_embedded_orientation (GdkPixbuf *src
);
Takes an existing pixbuf and checks for the presence of an associated "orientation" option, which may be provided by the jpeg loader (which reads the exif orientation tag) or the tiff loader (which reads the tiff orientation tag, and compensates it for the partial transforms performed by libtiff). If an orientation option/tag is present, the appropriate transform will be performed so that the pixbuf is oriented correctly.
Returns
A newly-created pixbuf, NULL
if
not enough memory could be allocated for it, or a reference to the
input pixbuf (with an increased reference count).
[transfer full]
Since: 2.12
gdk_pixbuf_fill ()
void gdk_pixbuf_fill (GdkPixbuf *pixbuf
,guint32 pixel
);
Clears a pixbuf to the given RGBA value, converting the RGBA value into the pixbuf's pixel format. The alpha will be ignored if the pixbuf doesn't have an alpha channel.