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Image Data in Memory
Synopsis
#include <gdk-pixbuf/gdk-pixbuf.h> GdkPixbuf* gdk_pixbuf_new (GdkColorspace colorspace, gboolean has_alpha, int bits_per_sample, int width, int height); GdkPixbuf* gdk_pixbuf_new_from_data (const guchar *data, GdkColorspace colorspace, gboolean has_alpha, int bits_per_sample, int width, int height, int rowstride, GdkPixbufDestroyNotify destroy_fn, gpointer destroy_fn_data); GdkPixbuf* gdk_pixbuf_new_from_xpm_data (const char **data); GdkPixbuf* gdk_pixbuf_copy (const GdkPixbuf *pixbuf); |
Description
The most basic way to create a pixbuf is to wrap an existing pixel buffer with a GdkPixbuf structure. You can use the gdk_pixbuf_new_from_data() function to do this You need to specify the destroy notification function that will be called when the data buffer needs to be freed; this will happen when a GdkPixbuf is finalized by the reference counting functions If you have a chunk of static data compiled into your application, you can pass in NULL as the destroy notification function so that the data will not be freed.
The gdk_pixbuf_new() function can be used as a convenience to create a pixbuf with an empty buffer. This is equivalent to allocating a data buffer using malloc() and then wrapping it with gdk_pixbuf_new_from_data(). The gdk_pixbuf_new() function will compute an optimal rowstride so that rendering can be performed with an efficient algorithm.
As a special case, you can use the gdk_pixbuf_new_from_xpm_data() function to create a pixbuf from inline XPM image data.
You can also copy an existing pixbuf with the gdk_pixbuf_copy() function. This is not the same as just doing a gdk_pixbuf_ref() on the old pixbuf; the copy function will actually duplicate the pixel data in memory and create a new GdkPixbuf structure for it.
Details
gdk_pixbuf_new ()
GdkPixbuf* gdk_pixbuf_new (GdkColorspace colorspace, gboolean has_alpha, int bits_per_sample, int width, int height); |
Creates a new GdkPixbuf structure and allocates a buffer for it. The buffer has an optimal rowstride. Note that the buffer is not cleared; you will have to fill it completely yourself.
| colorspace : | Color space for image. |
| has_alpha : | Whether the image should have transparency information. |
| bits_per_sample : | Number of bits per color sample. |
| width : | Width of image in pixels. |
| height : | Height of image in pixels. |
| Returns : | A newly-created GdkPixbuf with a reference count of 1, or NULL if not enough memory could be allocated for the image buffer. |
gdk_pixbuf_new_from_data ()
GdkPixbuf* gdk_pixbuf_new_from_data (const guchar *data,
GdkColorspace colorspace,
gboolean has_alpha,
int bits_per_sample,
int width,
int height,
int rowstride,
GdkPixbufDestroyNotify destroy_fn,
gpointer destroy_fn_data); |
Creates a new GdkPixbuf out of in-memory image data. Currently only RGB images with 8 bits per sample are supported.
| data : | Image data in 8-bit/sample packed format. |
| colorspace : | Colorspace for the image data. |
| has_alpha : | Whether the data has an opacity channel. |
| bits_per_sample : | Number of bits per sample. |
| width : | Width of the image in pixels. |
| height : | Height of the image in pixels. |
| rowstride : | Distance in bytes between rows. |
| destroy_fn : | Function used to free the data when the pixbuf's reference count drops to zero, or NULL if the data should not be freed. |
| destroy_fn_data : | Closure data to pass to the destroy notification function. |
| Returns : | A newly-created GdkPixbuf structure with a reference count of 1. |
gdk_pixbuf_new_from_xpm_data ()
GdkPixbuf* gdk_pixbuf_new_from_xpm_data (const char **data); |
Creates a new pixbuf by parsing XPM data in memory. This data is commonly the result of including an XPM file into a program's C source.