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GDK-PixBuf Reference Manual | |
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#include <gdk-pixbuf/gdk-pixdata.h> struct GdkPixdata; enum GdkPixdataType; enum GdkPixdataDumpType; #define GDK_PIXBUF_MAGIC_NUMBER #define GDK_PIXDATA_HEADER_LENGTH gpointer gdk_pixdata_from_pixbuf (GdkPixdata *pixdata,const GdkPixbuf *pixbuf,gboolean use_rle); GdkPixbuf * gdk_pixbuf_from_pixdata (const GdkPixdata *pixdata,gboolean copy_pixels,GError **error); guint8 * gdk_pixdata_serialize (const GdkPixdata *pixdata,guint *stream_length_p); gboolean gdk_pixdata_deserialize (GdkPixdata *pixdata,guint stream_length,const guint8 *stream,GError **error); GString * gdk_pixdata_to_csource (GdkPixdata *pixdata,const gchar *name,GdkPixdataDumpType dump_type);
Using GdkPixdata, images can be compiled into an application, making it unnecessary to refer to external image files at runtime. gdk-pixbuf includes a utility named gdk-pixbuf-csource, which can be used to convert image files into GdkPixdata structures suitable for inclusion in C sources. To convert the GdkPixdata structures back into GdkPixbufs, use gdk_pixbuf_from_pixdata.
struct GdkPixdata {
guint32 magic; /* GDK_PIXBUF_MAGIC_NUMBER */
gint32 length; /* <1 to disable length checks, otherwise:
* GDK_PIXDATA_HEADER_LENGTH + pixel_data length
*/
guint32 pixdata_type; /* GdkPixdataType */
guint32 rowstride;
guint32 width;
guint32 height;
guint8 *pixel_data;
};
A GdkPixdata contains pixbuf information in a form suitable for serialization and streaming.
guint32 |
magic number. A valid GdkPixdata structure must have GDK_PIXBUF_MAGIC_NUMBER here. |
gint32 |
less than 1 to disable length checks, otherwise
GDK_PIXDATA_HEADER_LENGTH + length of pixel_data. |
guint32 |
information about colorspace, sample width and encoding, in a GdkPixdataType. |
guint32 |
Distance in bytes between rows. |
guint32 |
Width of the image in pixels. |
guint32 |
Height of the image in pixels. |
guint8 * |
width x height pixels, encoded according to pixdata_type
and rowstride. |
typedef enum {
/* colorspace + alpha */
GDK_PIXDATA_COLOR_TYPE_RGB = 0x01,
GDK_PIXDATA_COLOR_TYPE_RGBA = 0x02,
GDK_PIXDATA_COLOR_TYPE_MASK = 0xff,
/* width, support 8bits only currently */
GDK_PIXDATA_SAMPLE_WIDTH_8 = 0x01 << 16,
GDK_PIXDATA_SAMPLE_WIDTH_MASK = 0x0f << 16,
/* encoding */
GDK_PIXDATA_ENCODING_RAW = 0x01 << 24,
GDK_PIXDATA_ENCODING_RLE = 0x02 << 24,
GDK_PIXDATA_ENCODING_MASK = 0x0f << 24
} GdkPixdataType;
An enumeration containing three sets of flags for a GdkPixdata struct: one for the used colorspace, one for the width of the samples and one for the encoding of the pixel data.
| each pixel has red, green and blue samples. | |
| each pixel has red, green and blue samples and an alpha value. | |
| mask for the colortype flags of the enum. | |
| each sample has 8 bits. | |
| mask for the sample width flags of the enum. | |
| the pixel data is in raw form. | |
| the pixel data is run-length encoded. Runs may be up to 127 bytes long; their length is stored in a single byte preceding the pixel data for the run. If a run is constant, its length byte has the high bit set and the pixel data consists of a single pixel which must be repeated. | |
| mask for the encoding flags of the enum. |
typedef enum {
/* type of source to save */
GDK_PIXDATA_DUMP_PIXDATA_STREAM = 0,
GDK_PIXDATA_DUMP_PIXDATA_STRUCT = 1,
GDK_PIXDATA_DUMP_MACROS = 2,
/* type of variables to use */
GDK_PIXDATA_DUMP_GTYPES = 0,
GDK_PIXDATA_DUMP_CTYPES = 1 << 8,
GDK_PIXDATA_DUMP_STATIC = 1 << 9,
GDK_PIXDATA_DUMP_CONST = 1 << 10,
/* save RLE decoder macro? */
GDK_PIXDATA_DUMP_RLE_DECODER = 1 << 16
} GdkPixdataDumpType;
An enumeration which is used by gdk_pixdata_to_csource() to
determine the form of C source to be generated. The three values
GDK_PIXDATA_DUMP_PIXDATA_STREAM, GDK_PIXDATA_DUMP_PIXDATA_STRUCT
and GDK_PIXDATA_DUMP_MACROS are mutually exclusive, as are
GDK_PIXBUF_DUMP_GTYPES and GDK_PIXBUF_DUMP_CTYPES. The remaining
elements are optional flags that can be freely added.
| Generate pixbuf data stream (a single string containing a serialized GdkPixdata structure in network byte order). | |
| Generate GdkPixdata structure (needs the GdkPixdata structure definition from gdk-pixdata.h). | |
Generate *_ROWSTRIDE,
*_WIDTH, *_HEIGHT,
*_BYTES_PER_PIXEL and
*_RLE_PIXEL_DATA or *_PIXEL_DATA
macro definitions for the image.
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| Generate GLib data types instead of standard C data types. | |
| Generate standard C data types instead of GLib data types. | |
| Generate static symbols. | |
| Generate const symbols. | |
Provide a *_RUN_LENGTH_DECODE(image_buf, rle_data, size, bpp)
macro definition to decode run-length encoded image data.
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#define GDK_PIXBUF_MAGIC_NUMBER (0x47646b50) /* 'GdkP' */
Magic number for GdkPixdata structures.
#define GDK_PIXDATA_HEADER_LENGTH (4 + 4 + 4 + 4 + 4 + 4)
The length of a GdkPixdata structure without the pixel_data pointer.
gpointer gdk_pixdata_from_pixbuf (GdkPixdata *pixdata,const GdkPixbuf *pixbuf,gboolean use_rle);
Converts a GdkPixbuf to a GdkPixdata. If use_rle is TRUE, the
pixel data is run-length encoded into newly-allocated memory and a
pointer to that memory is returned.
|
a GdkPixdata to fill. |
|
the data to fill pixdata with. |
|
whether to use run-length encoding for the pixel data. |
Returns : |
If ure_rle is TRUE, a pointer to the newly-allocated memory
for the run-length encoded pixel data, otherwise NULL. |
GdkPixbuf * gdk_pixbuf_from_pixdata (const GdkPixdata *pixdata,gboolean copy_pixels,GError **error);
Converts a GdkPixdata to a GdkPixbuf. If copy_pixels is TRUE or
if the pixel data is run-length-encoded, the pixel data is copied into
newly-allocated memory; otherwise it is reused.
|
a GdkPixdata to convert into a GdkPixbuf. |
|
whether to copy raw pixel data; run-length encoded pixel data is always copied. |
|
location to store possible errors. |
Returns : |
a new GdkPixbuf. |
guint8 * gdk_pixdata_serialize (const GdkPixdata *pixdata,guint *stream_length_p);
Serializes a GdkPixdata structure into a byte stream.
The byte stream consists of a straightforward writeout of the
GdkPixdata fields in network byte order, plus the pixel_data
bytes the structure points to.
|
a valid GdkPixdata structure to serialize. |
|
location to store the resulting stream length in. |
Returns : |
A newly-allocated string containing the serialized GdkPixdata structure. |
gboolean gdk_pixdata_deserialize (GdkPixdata *pixdata,guint stream_length,const guint8 *stream,GError **error);
Deserializes (reconstruct) a GdkPixdata structure from a byte stream.
The byte stream consists of a straightforward writeout of the
GdkPixdata fields in network byte order, plus the pixel_data
bytes the structure points to.
The pixdata contents are reconstructed byte by byte and are checked
for validity. This function may fail with GDK_PIXBUF_CORRUPT_IMAGE
or GDK_PIXBUF_ERROR_UNKNOWN_TYPE.
|
a GdkPixdata structure to be filled in. |
|
length of the stream used for deserialization. |
|
stream of bytes containing a serialized GdkPixdata structure. |
|
GError location to indicate failures (maybe NULL to ignore errors). |
Returns : |
Upon successful deserialization TRUE is returned,
FALSE otherwise. |
GString * gdk_pixdata_to_csource (GdkPixdata *pixdata,const gchar *name,GdkPixdataDumpType dump_type);
Generates C source code suitable for compiling images directly into programs.
GTK+ ships with a program called gdk-pixbuf-csource which offers a command line interface to this function.
|
a GdkPixdata to convert to C source. |
|
used for naming generated data structures or macros. |
|
a GdkPixdataDumpType determining the kind of C source to be generated. |
Returns : |
a newly-allocated string containing the C source form
of pixdata. |