XvShmCreateImage (3) - Linux Manuals

XvShmCreateImage: create an XvImage


XvCreateImage, XvShmCreateImage - create an XvImage


#include <X11/extensions/Xvlib.h>

XvImage * XvCreateImage (Display *dpy, XvPortID port,
                         int id, char *data,
                         int width, int height);

XvImage * XvShmCreateImage (Display *dpy, XvPortID port,
                            int id, char *data,
                            int width, int height,
                            XShmSegmentInfo *shminfo);


Specifies the connection to the X server.
Specifies the port the XvImage will be used with.
Specifies the format of the image to be created by the XvImageFormatValues id.
Specifies the image data.
width, height
Specifies the desired width and height of the image.


XvCreateImage(3) is similar to XCreateImage(3). XvShmCreateImage(3) is similar to XShmCreateImage(3). The library will allocate the XvImage structure and fill out all fields except for data. Width and height may be enlarged in some YUV formats. The size of the data buffer that needs to be allocated will be given in the data_size field in the XvImage. Image data is not allocated by this function. The client may pass a pointer to the preallocated memory as data or may allocate the memory and fill in the XvImage structure's data field after the data_size field has been filled out by the server. The XvImage structure may be freed by XFree(3). Shared memory segments are attached/detached with XShmAttach(3)/XShmDetach(3).


XvImage has the following structure:

typedef struct {
int id;
int width, height;
int data_size;
int num_planes;
int *pitches;
int *offsets;
char *data;
XPointer obdata; } XvImage;

A descriptor for the format from the XvImageFormatValues structure returned by XvListImageFormats(3).
width, height
The width and height of the image in pixels.
The size of the data buffer in bytes.
The number of image planes.
An array of size num_planes indicating the scanline pitch in bytes. Each plane may have a different pitch.
An array of size num_planes indicating the byte offset from data to the start of each plane.
A pointer to the start of the data buffer.
A private field for holding SHM info. This field will be set up by the client libraries so the programmer will generally need not be concerned with this field.


Generated if the requested port does not exist.
Generated if the X server was unable to allocate resources required to complete the operation.
Generated if incompatible arguments were supplied, such as a port that isn't capable of displaying XvImages.