.TH XvCreateImage 3 "libXv 1.0.12" "X Version 11" "libXv Functions"
.SH NAME
XvCreateImage, XvShmCreateImage \- create an XvImage
.\"
.SH SYNOPSIS
.B #include <X11/extensions/Xvlib.h>
.sp
.nf
.BI "XvImage * XvCreateImage (Display *" dpy ", XvPortID " port ","
.BI "                         int " id ", char *" data ","
.BI "                         int " width ", int " height ");"
.sp
.BI "XvImage * XvShmCreateImage (Display *" dpy ", XvPortID " port ","
.BI "                            int " id ", char *" data ","
.BI "                            int " width ", int " height ","
.BI "                            XShmSegmentInfo *" shminfo ");"
.fi
.SH ARGUMENTS
.\"
.IP \fIdpy\fR 8
Specifies the connection to the X server.
.IP \fIport\fR 8
Specifies the port the XvImage will be used with.
.IP \fIid\fR 8
Specifies the format of the image to be created by the XvImageFormatValues id.
.IP \fIdata\fR 8
Specifies the image data.
.IP "\fIwidth\fR, \fIheight\fR" 8
Specifies the desired width and height of the image.
.\"
.SH DESCRIPTION
.BR XvCreateImage (3)
is similar to
.BR XCreateImage (3).
.BR XvShmCreateImage (3)
is similar to
.BR XShmCreateImage (3).
The library will allocate the XvImage structure and fill out all
fields except for \fIdata\fR.  \fIWidth\fR and \fIheight\fR may be
enlarged in some YUV formats.  The size of the data buffer that needs
to be allocated will be given in the \fIdata_size\fR field in the XvImage.
Image data is not allocated by this function.  The client may pass a pointer
to the preallocated memory as \fIdata\fR or may allocate the memory and fill in
the XvImage structure's data field after the \fIdata_size\fR field has
been filled out by the server.  The XvImage structure may be freed by
.BR XFree (3).
Shared memory segments are attached/detached with
.BR XShmAttach (3)/ XShmDetach (3).
.SH RETURN VALUES
XvImage has the following structure:
.EX

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

.EE
.IP \fIid\fR 8
A descriptor for the format from the XvImageFormatValues structure
returned by
.BR XvListImageFormats (3).
.IP "\fIwidth, height\fR" 8
The width and height of the image in pixels.
.IP \fIdata_size\fR 8
The size of the data buffer in bytes.
.IP \fInum_planes\fR 8
The number of image planes.
.IP \fIpitches\fR 8
An array of size \fInum_planes\fR indicating the scanline pitch
in bytes.  Each plane may have a different pitch.
.IP \fIoffsets\fR 8
An array of size \fInum_planes\fR indicating the byte offset
from \fIdata\fR to the start of each plane.
.IP \fIdata\fR 8
A pointer to the start of the data buffer.
.IP \fIobdata\fR 8
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.
.\"
.SH DIAGNOSTICS
.IP [XvBadPort] 8
Generated if the requested port does not exist.
.IP [XvBadAlloc] 8
Generated if the X server was unable to allocate resources required
to complete the operation.
.IP [BadMatch] 8
Generated if incompatible arguments were supplied, such as a port that
isn't capable of displaying XvImages.
.\"
.SH SEE ALSO
.BR XvListImageFormats (3),
.BR XCreateImage (3),
.BR XShmCreateImage (3),
.BR XShmAttach (3),
.BR XShmDetach (3).