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   subimage_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 created or returned by Xlib do not need to be initialized in this fashion.

       This function returns a nonzero status if initialization of the structure 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  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(3)
       Xlib - C Language X Interface