XCreateImage(3X11)      COMMAND REFERENCE      XCreateImage(3X11)



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

SYNOPSIS
     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.



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XCreateImage(3X11)      COMMAND REFERENCE      XCreateImage(3X11)



     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



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XCreateImage(3X11)      COMMAND REFERENCE      XCreateImage(3X11)



     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











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