XPutImage(), XGetImage(), XGetSubImage() - transfer images
XPutImage (Display *display, Drawable d, GC gc,
XImage *image, int src_x, src_y, int dest_x,
int dest_y, unsigned int width, height)
XImage *XGetImage (Display *display, Drawable d, int x,
int y, unsigned int width, height,
unsigned long plane_mask, int format)
XImage *XGetSubImage (Display *display, Drawable d, int x,
int y, unsigned int width, int height,
unsigned long plane_mask, int format,
XImage *dest_image, int dest_x,
int dest_y)
The XPutImage(3) function combines an image in memory with a rectangle of the specified drawable. If XYBitmap format is used, the depth of the image must be one, or a BadMatch error results. The foreground pixel in the GC defines the source for the one bits in the image, and the background pixel defines the source for the zero bits. For XYPixmap and ZPixmap, the depth of the image must match the depth of the drawable, or a BadMatch error results. The section of the image defined by the src_x, src_y, width, and height arguments is drawn on the specified part of the drawable.
This function uses these GC components: function, plane-mask, subwindow-mode, clip-x-origin, clip-y-origin, and clip-mask. It also uses these GC mode-dependent components: foreground and background.
XPutImage(3) cangenerate BadDrawable, BadGC, BadMatch, and BadValue errors.
The XGetImage(3) function returns a pointer to an XImage structure. This structure provides you with the contents of the specified rectangle of the drawable in the format you specify. If the format argument is XYPixmap, the image contains only the bit planes you passed to the plane_mask argument. If the plane_mask argument only requests a subset of the planes of the display, the depth of the returned image will be the number of planes requested. If the format argument is ZPixmap, XGetImage(3) returns as zero the bits in all planes not specified in the plane_mask argument. The function performs no range checking on the values in plane_mask and ignores extraneous bits.
XGetImage(3) returns the depth of the image to the depth member of the XImage structure. The depth of the image is as specified when the drawable was created, except when getting a subset of the planes in XYPixmap format, when the depth is given by the number of bits set to 1 in plane_mask.
If the drawable is a pixmap, the given rectangle must be wholly contained within the pixmap, or a BadMatch error results. If the drawable is a window, the window must be viewable, and it must be the case that if there were no inferiors or overlapping windows, the specified rectangle of the window would be fully visible on the screen and wholly contained within the outside edges of the window, or a BadMatch error results. Note that the borders of the window can be included and read with this request. If the window has backing-store, the backing-store contents are returned for regions of the window that are obscured by noninferior windows. If the window does not have backing-store, the returned contents of such obscured regions are undefined. The returned contents of visible regions of inferiors of a different depth than the specified window's depth are also undefined. The pointer cursor image is not included in the returned contents. If a problem occurs, XGetImage(3) returns NULL.
XGetImage(3) can generate BadDrawable, BadMatch, and BadValue errors.
The XGetSubImage(3) function updates dest_image with the specified subimage in the same manner as XGetImage(3). If the format argument is XYPixmap, the image contains only the bit planes you passed to the plane_mask argument. If the format argument is ZPixmap, XGetSubImage(3) returns as zero the bits in all planes not specified in the plane_mask argument. The function performs no range checking on the values in plane_mask and ignores extraneous bits. As a convenience, XGetSubImage(3) returns a pointer to the same XImage structure specified by dest_image.
The depth of the destination XImage structure must be the same as that of the drawable. If the specified subimage does not fit at the specified location on the destination image, the right and bottom edges are clipped. If the drawable is a pixmap, the given rectangle must be wholly contained within the pixmap, or a BadMatch error results. If the drawable is a window, the window must be viewable, and it must be the case that if there were no inferiors or overlapping windows, the specified rectangle of the window would be fully visible on the screen and wholly contained within the outside edges of the window, or a BadMatch error results. If the window has backing-store, then the backing-store contents are returned for regions of the window that are obscured by noninferior windows. If the window does not have backing-store, the returned contents of such obscured regions are undefined. The returned contents of visible regions of inferiors of a different depth than the specified window's depth are also undefined. If a problem occurs, XGetSubImage(3) returns NULL.
XGetSubImage(3) can generate BadDrawable, BadGC, BadMatch, and BadValue errors.
Xlib