Query: xgetpixel
OS: ultrix
Section: 3x11
Links: ultrix man pages all man pages
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XCreateImage(3X11) MIT X11R4 XCreateImage(3X11) Name XCreateImage, XGetPixel, XPutPixel, XSubImage, XAddPixel, XDestroyImage - image utilities Syntax 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 a pointer to 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 or 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 a pointer to the visual. width Specifies the width of the image, in pixels. ximage Specifies a pointer to the image. x y Specify the x and y coordinates. Description The function allocates the memory needed for an 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 structure. The red, green, and blue mask values are defined for Z format images only and are derived from the 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 or the destroy procedure that the 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 offset to a Z format 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 function returns the specified pixel from the named image. The pixel value is returned in normalized format (that is, the least-sig- nificant byte of the long is the least-significant byte of the pixel). The image must contain the x and y coordinates. The 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 coordi- nates. The function creates a new image that is a subsection of an existing one. It allocates the memory necessary for the new 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 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 function deallocates the memory associated with the structure. See Also XPutImage(3X11) X Window System: The Complete Reference, Second Edition, Robert W. Scheifler and James Gettys XCreateImage(3X11)