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<HTML><HEAD><TITLE>Xlib Programming Manual: XGetImage</TITLE></HEAD><BODY><H1 ALIGN=center>XGetImage</H1><H2>Syntax</H2>This function specifically supports rudimentary screen dumps.<!.IN "XGetImage" "" "@DEF@"><CODE><PRE><A HREF="images.html#XImage">XImage</A> *XGetImage(<B>display</B>, <B>d</B>, <B>x</B>, <B>y</B>, <B>width</B>, <B>height</B>, <B>plane_mask</B>, <B>format</B>) <A HREF="../display/opening.html#Display">Display</A> *<B>display</B>; Drawable <B>d</B>; int <B>x</B>, <B>y</B>; unsigned int <B>width</B>, <B>height</B>; unsigned long <B>plane_mask</B>; int <B>format</B>;</PRE></CODE><H2>Arguments</H2><TABLE><TR><TD> <B>display</B><TD> Specifies the connection to the X server.<TR><TD> <B>d</B><TD> Specifies the drawable. <TR><TD> <B>x</B><BR> <B>y</B><TD> Specify the x and y coordinates, which are relative to the origin of the drawable and define the upper-left corner of the rectangle.<TR><TD> <B>width</B><BR> <B>height</B><TD> Specify the width and height of the subimage, which define the dimensions of the rectangle.<TR><TD> <B>plane_mask</B><TD> Specifies the plane mask.<TR><TD> <B>format</B><TD> Specifies the format for the image.You can pass<B>XYPixmap</B>or <B>ZPixmap</B> .</TABLE><H2>Description</H2>The<B>XGetImage()</B>function returns a pointer to an<A HREF="images.html#XImage">XImage</A>structure.This structure provides you with the contents of the specified rectangle ofthe drawable in the format you specify.If the format argument is <B>XYPixmap</B> ,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 thedisplay, the depth of the returned image will be the number of planesrequested.If the format argument is <B>ZPixmap</B> ,<B>XGetImage()</B>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 ignoresextraneous bits.<P><B>XGetImage()</B>returns the depth of the image to the depth member of the<A HREF="images.html#XImage">XImage</A>structure.The depth of the image is as specified when the drawable was created,except when getting a subset of the planes in <B>XYPixmap</B>format, when the depth is given by the number of bits set to 1 in plane_mask.<P>If the drawable is a pixmap, the given rectangle must be wholly contained within the pixmap, or a<B>BadMatch</B>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 screenand wholly contained within the outside edges of the window,or a<B>BadMatch</B>error results.Note that the borders of the window can be included and read withthis request.If the window has backing-store, the backing-store contents arereturned for regions of the window that are obscured by noninferiorwindows. If the window does not have backing-store,the returned contents of such obscured regions are undefined.The returned contents of visible regions of inferiorsof 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,<B>XGetImage()</B>returns NULL.<P><B>XGetImage()</B>can generate<B>BadDrawable</B> ,<B>BadMatch</B> ,and<B>BadValue</B> errors.<H2>Diagnostics</H2><TABLE><TR><TD><B>BadDrawable</B><TD>A value for a Drawable argument does not name a defined Window or Pixmap.<TR><TD><B>BadMatch</B><TD>An<B><A HREF="../window/create.html#InputClass">InputOnly</A></B>window is used as a Drawable.<TR><TD><B>BadMatch</B><TD>Some argument or pair of arguments has the correct type and range but fails to match in some other way required by the request.<TR><TD><B>BadValue</B><TD> Some numeric value falls outside the range of values accepted by the request. Unless a specific range is specified for an argument, the full range defined by the argument's type is accepted. Any argument defined as a set of alternatives can generate this error.</TABLE><H2>See also</H2><B><A HREF="../utilities/XAddPixel.html">XAddPixel()</A></B>,<B><A HREF="../utilities/XCreateImage.html">XCreateImage()</A></B>,<B><A HREF="../utilities/XDestroyImage.html">XDestroyImage()</A></B>,<B><A HREF="../utilities/XGetPixel.html">XGetPixel()</A></B>,<B><A HREF="XInitImage.html">XInitImage()</A></B>,<B><A HREF="XPutImage.html">XPutImage()</A></B>,<B><A HREF="../utilities/XPutPixel.html">XPutPixel()</A></B>,<B><A HREF="XGetSubImage.html">XGetSubImage()</A></B>,"<A HREF="images.html">Transferring Images between Client and Server</A>".<HR><ADDRESS><A HREF="http://tronche.com/">Christophe Tronche</A>, <A HREF="mailto:ch.tronche@computer.org">ch.tronche@computer.org</A></ADDRESS></BODY></HTML>⌨️ 快捷键说明
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