XCreateImage(3X11)            SDK X11 R4.11MU05           XCreateImage(3X11)


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

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

       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, subimagewidth, subimageheight)
             XImage *ximage;
             int x;
             int y;
             unsigned int subimagewidth;
             unsigned int subimageheight;

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

       XDestroyImage(ximage)
               XImage *ximage;

ARGUMENTS
       bitmappad
                 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.

       bytesperline
                 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.

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

       subimagewidth
                 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.

       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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