XCreateImage

XCreateImage(3X11)		XLIB FUNCTIONS		   XCreateImage(3X11)



NAME
       XInitImage, XCreateImage, XGetPixel, XPutPixel, XSubImage, XAddPixel,
       XDestroyImage - image utilities

SYNTAX
       Status XInitImage(XImage *image);

       XImage *XCreateImage(Display *display, Visual *visual, unsigned int
	      depth, int format, int offset, char *data, unsigned int width,
	      unsigned int height, int bitmap_pad, int bytes_per_line);

       unsigned long XGetPixel(XImage *ximage, int x, int y);

       int XPutPixel(XImage *ximage, int x, int y, unsigned long pixel);

       XImage *XSubImage(XImage *ximage, int x, int y, unsigned int subim-
	      age_width, unsigned int subimage_height);

       int XAddPixel(XImage *ximage, long value);

       int XDestroyImage(XImage *ximage);

ARGUMENTS
       bitmap_pad
		 Specifies the quantum of a scanline (8, 16, or 32).  In
		 other words, the start of one scanline is separated in
		 client memory from the start of the next scanline by an
		 integer multiple of this many bits.

       bytes_per_line
		 Specifies the number of bytes in the client image between
		 the start of one scanline and the start of the next.

       data	 Specifies the image data.

       depth	 Specifies the depth of the image.

       display	 Specifies the connection to the X server.

       format	 Specifies the format for the image.  You can pass XYBitmap,
		 XYPixmap, or ZPixmap.

       height	 Specifies the height of the image, in pixels.

       offset	 Specifies the number of pixels to ignore at the beginning of
		 the scanline.

       pixel	 Specifies the new pixel value.

       subimage_height
		 Specifies the height of the new subimage, in pixels.

       subimage_width
		 Specifies the width of the new subimage, in pixels.

       value	 Specifies the constant value that is to be added.

       visual	 Specifies the Visual structure.

       width	 Specifies the width of the image, in pixels.

       ximage	 Specifies the image.

       x
       y	 Specify the x and y coordinates.

DESCRIPTION
       The XInitImage function initializes the internal image manipulation
       routines of an image structure, based on the values of the various
       structure members.  All fields other than the manipulation routines
       must already be initialized.  If the bytes_per_line member is zero,
       XInitImage will assume the image data is contiguous in memory and set
       the bytes_per_line member to an appropriate value based on the other
       members; otherwise, the value of bytes_per_line is not changed.	All
       of the manipulation routines are initialized to functions that other
       Xlib image manipulation functions need to operate on the type of image
       specified by the rest of the structure.

       This function must be called for any image constructed by the client
       before passing it to any other Xlib function.  Image structures cre-
       ated or returned by Xlib do not need to be initialized in this fash-
       ion.

       This function returns a nonzero status if initialization of the struc-
       ture is successful.  It returns zero if it detected some error or
       inconsistency in the structure, in which case the image is not
       changed.

       The XCreateImage function allocates the memory needed for an XImage
       structure for the specified display but does not allocate space for
       the image itself.  Rather, it initializes the structure byte-order,
       bit-order, and bitmap-unit values from the display and returns a
       pointer to the XImage structure.	 The red, green, and blue mask values
       are defined for Z format images only and are derived from the Visual
       structure passed in.  Other values also are passed in.  The offset
       permits the rapid displaying of the image without requiring each scan-
       line to be shifted into position.  If you pass a zero value in
       bytes_per_line, Xlib assumes that the scanlines are contiguous in mem-
       ory and calculates the value of bytes_per_line itself.

       Note that when the image is created using XCreateImage, XGetImage, or
       XSubImage, the destroy procedure that the XDestroyImage function calls
       frees both the image structure and the data pointed to by the image
       structure.

       The basic functions used to get a pixel, set a pixel, create a subim-
       age, and add a constant value to an image are defined in the image
       object.	The functions in this section are really macro invocations of
       the functions in the image object and are defined in <X11/Xutil.h>.

       The XGetPixel function returns the specified pixel from the named
       image.  The pixel value is returned in normalized format (that is, the
       least significant byte of the long is the least significant byte of
       the pixel).  The image must contain the x and y coordinates.

       The XPutPixel function overwrites the pixel in the named image with
       the specified pixel value.  The input pixel value must be in normal-
       ized format (that is, the least significant byte of the long is the
       least significant byte of the pixel).  The image must contain the x
       and y coordinates.

       The XSubImage function creates a new image that is a subsection of an
       existing one.  It allocates the memory necessary for the new XImage
       structure and returns a pointer to the new image.  The data is copied
       from the source image, and the image must contain the rectangle
       defined by x, y, subimage_width, and subimage_height.

       The XAddPixel function adds a constant value to every pixel in an
       image.  It is useful when you have a base pixel value from allocating
       color resources and need to manipulate the image to that form.

       The XDestroyImage function deallocates the memory associated with the
       XImage structure.

SEE ALSO
       XPutImage(3X11)
       Xlib - C Language X Interface



							   XCreateImage(3X11)