Manpages - XvCreateImage.3

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);

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.

*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;

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.

[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.

*XvListImageFormats*(3), *XCreateImage*(3), *XShmCreateImage*(3), *XShmAttach*(3), *XShmDetach*(3).