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/* $Id: Helper.cpp $ */
/** @file
* VBoxFB - Helper routines.
*/
/*
* Copyright (C) 2006-2023 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, in version 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* SPDX-License-Identifier: GPL-3.0-only
*/
#include "VBoxFB.h"
#include "Helper.h"
/**
* Globals
*/
videoMode g_videoModes[MAX_VIDEOMODES] = {{0}};
uint32_t g_numVideoModes = 0;
/**
* callback handler for populating the supported video modes
*
* @returns callback success indicator
* @param width width in pixels of the current video mode
* @param height height in pixels of the current video mode
* @param bpp bits per pixel of the current video mode
* @param callbackdata user data pointer
*/
DFBEnumerationResult enumVideoModesHandler(int width, int height, int bpp, void *callbackdata)
{
RT_NOREF(callbackdata);
if (g_numVideoModes >= MAX_VIDEOMODES)
{
return DFENUM_CANCEL;
}
// don't take palette based modes
if (bpp >= 16)
{
// don't take modes we already have (I have seen many cases where
// DirectFB returns the same modes several times)
int32_t existingMode = getBestVideoMode(width, height, bpp);
if ( existingMode == -1
|| g_videoModes[existingMode].width != (uint32_t)width
|| g_videoModes[existingMode].height != (uint32_t)height
|| g_videoModes[existingMode].bpp != (uint32_t)bpp)
{
g_videoModes[g_numVideoModes].width = (uint32_t)width;
g_videoModes[g_numVideoModes].height = (uint32_t)height;
g_videoModes[g_numVideoModes].bpp = (uint32_t)bpp;
g_numVideoModes++;
}
}
return DFENUM_OK;
}
/**
* Returns the best fitting video mode for the given characteristics.
*
* @returns index of the best video mode, -1 if no suitable mode found
* @param width requested width
* @param height requested height
* @param bpp requested bit depth
*/
int32_t getBestVideoMode(uint32_t width, uint32_t height, uint32_t bpp)
{
int32_t bestMode = -1;
for (uint32_t i = 0; i < g_numVideoModes; i++)
{
// is this mode compatible?
if (g_videoModes[i].width >= width && g_videoModes[i].height >= height && g_videoModes[i].bpp >= bpp)
{
// first suitable mode?
if (bestMode == -1)
bestMode = i;
else
{
// is it better than the one we got before?
if ( g_videoModes[i].width < g_videoModes[bestMode].width
|| g_videoModes[i].height < g_videoModes[bestMode].height
|| g_videoModes[i].bpp < g_videoModes[bestMode].bpp)
{
bestMode = i;
}
}
}
}
return bestMode;
}
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