Tribblix: manual page: XvCreateImage.3

XvCreateImage(3) libXv Functions XvCreateImage(3)

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