XCreateImage(3X11)          X Version 11(Release 5)          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;

      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;

      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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      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 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.





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      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 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 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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