MirOS Manual: XAddPixel(3), XCreateImage(3), XDestroyImage(3), XGetPixel(3), XInitImage(3), XPutPixel(3), XSubImage(3)


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

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.

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

     subimage_height
               Specifies the height of the new subimage, in pix-
               els.

     subimage_width
               Specifies the width of the new subimage, in pix-
               els.

     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 mani-
     pulation 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 struc-
     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 per-
     mits the rapid displaying of the image without requiring

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

     each scanline to be shifted into position. If you pass a
     zero value in bytes_per_line, Xlib assumes that the scan-
     lines 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 for-
     mat (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 subsec-
     tion 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

XFree86                   Version 4.5.0                         3

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