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

       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