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XCreateImage(3X11)	       XLIB FUNCTIONS		   XCreateImage(3X11)



NAME
  XInitImage, XCreateImage, XGetPixel, XPutPixel, XSubImage, XAddPixel, XDes-
  troyImage - image utilities

SYNTAX
  Status XInitImage(image)
	XImage *image;

  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.

  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 rou-
  tines 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 ini-
  tialized to functions that other Xlib image manipulation functions need to
  operate on the 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 struc-
  ture 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 XSu-
  bImage, 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 &lt;X11/Xutil.h&gt;.

  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 struc-
  ture 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 XIm-
  age structure.

SEE ALSO
  XPutImage(3X11)
  Xlib - C Language X Interface


































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