XCreateImage(3X11)                   BSD                    XCreateImage(3X11)



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

SYNTAX
     XImage *XCreateImage(display, visual, depth, format, offset, data, width,
     height, bitmap_pad,
                             bytes_per_line)
           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, x, y)
           XImage *ximage;
           int x;
           int y;

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

     XImage *XSubImage(ximage, x, y, subimage_width, subimage_height)
           XImage *ximage;
           int x;
           int y;
           unsigned int subimage_width;
           unsigned int subimage_height;

     XAddPixel(ximage, value)
           XImage *ximage;
           long value;

     int XDestroyImage(ximage)
             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 a pointer to 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 a pointer to the visual.

     width     Specifies the width of the image, in pixels.

     ximage    Specifies a pointer to the image.

     x
     y         Specify the x and y coordinates.

DESCRIPTION
     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 scanline to be shifted
     into position.  If you pass a zero value in bytes_per_line, Xlib assumes
     that the scanlines are contiguous in memory 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 subimage,
     and add a constant offset to a Z format 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 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 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