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XCreateImage(3)                                XLIB FUNCTIONS                                XCreateImage(3)



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 subim-age_height); subimage_height);
              age_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 scan-line scanline
                 line is separated in client memory from the start of the next scanline by an integer multi-ple multiple
                 ple 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 rou-tines routines
       tines 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 dis-play display
       play but does not allocate space for the image itself.  Rather, it initializes the structure byte-order, byteorder,
       order, bit-order, and bitmap-unit values from the display and returns a pointer to the XImage struc-ture. structure.
       ture.  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 dis-playing displaying
       playing 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 proce-dure procedure
       dure 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, subim-age_width, subimage_width,
       age_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



X Version 11                                    libX11 1.2.1                                 XCreateImage(3)