px4-firmware/nuttx/graphics/nxmu/nx_requestbkgd.c

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/****************************************************************************
* graphics/nxmu/nx_requestbkgd.c
*
* Copyright (C) 2008-2009, 2011-2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/nx/nx.h>
#include "nxfe.h"
/****************************************************************************
* Pre-Processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nx_requestbkgd
*
* Description:
* NX normally controls a separate window called the background window.
* It repaints the window as necessary using only a solid color fill. The
* background window always represents the entire screen and is always
* below other windows. It is useful for an application to control the
* background window in the following conditions:
*
* - If you want to implement a windowless solution. The single screen
* can be used to creat a truly simple graphic environment. In this
* case, you should probably also de-select CONFIG_NX_MULTIUSER as well.
* - When you want more on the background than a solid color. For
* example, if you want an image in the background, or animations in the
* background, or live video, etc.
*
* This API only requests the handle of the background window. That
* handle will be returned asynchronously in a subsequent position and
* redraw callbacks.
*
*
* Cautions:
* - The following should never be called using the background window.
* They are guaranteed to cause severe crashes:
*
* nx_setposition, nx_setsize, nx_raise, nx_lower.
*
* - Neither nx_opengbwindow or nx_closebgwindow should be called more than
* once. Multiple instances of the background window are not supported.
*
* Input Parameters:
* handle - The handle returned by nx_connect
* cb - Callbacks to use for processing background window events
* arg - User provided argument (see nx_openwindow, nx_constructwindow)
*
* Return:
* OK: Success; ERROR of failure with errno set appropriately.
*
****************************************************************************/
int nx_requestbkgd(NXHANDLE handle, FAR const struct nx_callback_s *cb,
FAR void *arg)
{
FAR struct nxfe_conn_s *conn = (FAR struct nxfe_conn_s *)handle;
struct nxsvrmsg_requestbkgd_s outmsg;
#ifdef CONFIG_DEBUG
if (!conn || !cb)
{
errno = EINVAL;
return ERROR;
}
#endif
/* Request access to the background window from the server */
outmsg.msgid = NX_SVRMSG_REQUESTBKGD;
outmsg.conn = conn;
outmsg.cb = cb;
outmsg.arg = arg;
return nxmu_sendserver(conn, &outmsg, sizeof(struct nxsvrmsg_requestbkgd_s));
}