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)