PEXUtDBFront(3G)

Name

PEXUtDBFront − reconfigure the window to render in the front buffer

Syntax

int PEXUtDBFront(Display *dpy, Window win, int front, Drawable *drw_id_return)

Parameters

dpyA pointer to a display structure returned by a successful XOpenDisplay call.

winThe resource identifier of the window for which the buffers are configured.

frontfront indicates whether the window is configured to render into the front (i.e. the displayed or visible) buffer. A value of means the window is configured to render into the back (i.e. the non-visible buffer). A value of means the window is configured to render into the front buffer.

drw_id_return
drw_id_return is a pointer to a drawable identifier. This is the drawable identifier to be used for subsequent rendering calls for X and PEX. For example, this drawable identifier should be used for or as well as for X rendering calls like The returned value is a null pointer if the function is unsuccessful.

Returns

The function returns a value of zero if it is successful; a non-zero return value indicates failure. The following are the meaning of the different non-zero return values:

•A return value of means that rendering to the front buffer is not supported on the specified drawable. The application can still accomplish rendering to the front buffer by turning double-buffering off via See the Restrictions below.

•A return value of means that rendering to the front buffer is supported, but the function failed to enable rendering to the front buffer for some reason.

Description

The function configures a window, which is already configured for double-buffering, to render into the displayed buffer (i.e., the front buffer) if front == If the window is not configured for double-buffering, the function will simply return the specified window identifier.

and continue to clear the back buffer regardless of the state of rendering to the front buffer.

Restrictions

If it is necessary to ensure that all actions have completed before proceeding, the application should call after calling

This function should not be called with a window into which PEX is rendering. should be called prior to If the application desires to render into the front buffer without clearing, and the PEX server is version 5.1, the renderer’s clear_image flag should be set to before calling

may not succeed on all devices. However, if does fail, rendering to the front buffer can still be accomplished by turning double-buffering off via It is recommended that the application first call since, if it is supported, it is mostly likely a higher performance method than switching double-buffering on and off with

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