NAME
XvCreateImage, XvShmCreateImage - create an XvImage
SYNOPSIS
#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);
ARGUMENTS
dpy Specifies the connection to the X server.
port Specifies the port the XvImage will be used with.
id Specifies the format of the image to be created by the
XvImageFormatValues id.
data Specifies the image data.
width, height
Specifies the desired width and height of the image.
DESCRIPTION
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).
RETURN VALUES
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;
id A descriptor for the format from the XvImageFormatValues
structure returned by XvListImageFormats(3).
width, height
The width and height of the image in pixels.
data_size
The size of the data buffer in bytes.
num_planes
The number of image planes.
pitches An array of size num_planes indicating the scanline pitch in
bytes. Each plane may have a different pitch.
offsets An array of size num_planes indicating the byte offset from
data to the start of each plane.
data A pointer to the start of the data buffer.
obdata 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.
DIAGNOSTICS
[XvBadPort]
Generated if the requested port does not exist.
[XvBadAlloc]
Generated if the X server was unable to allocate resources
required to complete the operation.
[BadMatch]
Generated if incompatible arguments were supplied, such as a
port that isn’t capable of displaying XvImages.
SEE ALSO
XvListImageFormats(3), XCreateImage(3), XShmCreateImage(3),
XShmAttach(3), XShmDetach(3).