XGetImage()XGetImage()NameXGetImage – place contents of a rectangle from drawable into an image.
Synopsis
XImage *XGetImage(display, drawable, x, y, width, height,
plane_mask, format)
Display *display;
Drawable drawable;
int x, y;
unsigned int width, height;
unsigned long plane_mask;
int format;
Arguments
display Specifies a connection to an X server; returned from
XOpenDisplay().
drawable Specifies the drawable to get the data from.
x Specify the x and y coordinates of the upper-left corner of
y the rectangle, relative to the origin of the drawable.
width Specify the width and height in pixels of the image.
height
plane_mask
Specifies a plane mask that indicates which planes are repre‐
sented in the image.
format Specifies the format for the image. Pass either XYPixmap or
ZPixmap.
Returns
The created image.
DescriptionXGetImage() dumps the contents of the specified rectangle, a drawable,
into a client-side XImage structure, in the format you specify.
Depending on which format you pass to the format argument, the function
does the following:
· If the format is XYPixmap, the function gets only the bit planes you
passed to the plane_mask argument.
· If the format is ZPixmap, the function sets to 0 the bits in all
planes not specified in the plane_mask argument. The function per‐
forms no range checking on the values in plane_mask, and ignores
extraneous bits.
XGetImage() returns the depth of the image to the depth member of the
XImage structure. This depth is as specified when the drawable was
created.
If the drawable is a pixmap, the specified rectangle must be completely
inside the pixmap, or a BadMatch error will occur, and the visual field
in the image will be None. If XGetImage() fails, it returns NULL. If
the drawable is a window, the window must be viewable, and the speci‐
fied rectangle must not go off the edge of the screen. Otherwise, a
BadMatch error will occur. If the drawable is a window, the visual
argument will return the visual specified when the drawable was cre‐
ated.
The returned image will include any visible portions of inferiors con‐
tained in the rectangle. The image will not include the cursor. The
specified area can include the borders. The returned contents of visi‐
ble regions of inferiors of different depth than the specified window
are undefined.
If the window has a backing-store, the backing-store contents are
returned for regions of the window that are obscured by noninferior
windows. Otherwise, the return contents of such obscured regions are
undefined.
The data in the image structure is stored in the server's natural byte-
and bit-order.
For more information, see Volume One, Chapter 6, Drawing Graphics and
Text.
Errors
BadDrawable
BadMatch See the "Description" section above.
BadValue
See AlsoXImageByteOrder(), XAddPixel(), XCreateImage(), XDestroyImage(), XGet‐
Pixel(), XGetSubImage(), XPutImage(), XPutPixel(), XSubImage().
Xlib - Images XGetImage()