This repository has been archived by the owner on Feb 11, 2021. It is now read-only.
SDL_x11gamma.c
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/*
SDL - Simple DirectMedia Layer
Copyright (C) 1997-2006 Sam Lantinga
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Sam Lantinga
slouken@libsdl.org
*/
#include "SDL_config.h"
#include "../SDL_sysvideo.h"
#include "SDL_x11video.h"
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static int numCmaps = 0;
typedef struct
{
Display *display;
int scrNum;
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Colormap colormap;
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XStandardColormap cmap;
Visual visual;
} cmapTableEntry;
cmapTableEntry *cmapTable = NULL;
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/* To reduce the overhead as much as possible lets do as little as
possible. When we do have to create a colormap keep track of it and
reuse it. We're going to do this for both DirectColor and
PseudoColor colormaps. */
Colormap
X11_LookupColormap(Display * display, int scrNum, VisualID vid)
{
int i;
for (i = 0; i < numCmaps; i++) {
if (cmapTable[i].display == display &&
cmapTable[i].scrNum == scrNum &&
cmapTable[i].cmap.visualid == vid) {
return cmapTable[i].cmap.colormap;
}
}
return 0;
}
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void
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X11_TrackColormap(Display * display, int scrNum, Colormap colormap,
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XStandardColormap * cmap, Visual * visual)
{
int i;
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/* search the table to find out if we already have this one. We
only want one entry for each display, screen number, visualid,
and colormap combination */
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for (i = 0; i < numCmaps; i++) {
if (cmapTable[i].display == display &&
cmapTable[i].scrNum == scrNum &&
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cmapTable[i].cmap.visualid == cmap->visualid &&
cmapTable[i].cmap.colormap == colormap) {
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return;
}
}
/* increase the table by one entry. If the table is NULL create the
first entrty */
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cmapTable =
SDL_realloc(cmapTable, (numCmaps + 1) * sizeof(cmapTableEntry));
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if (NULL == cmapTable) {
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SDL_SetError("Out of memory in X11_TrackColormap()");
return;
}
cmapTable[numCmaps].display = display;
cmapTable[numCmaps].scrNum = scrNum;
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cmapTable[numCmaps].colormap = colormap;
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SDL_memcpy(&cmapTable[numCmaps].cmap, cmap, sizeof(XStandardColormap));
SDL_memcpy(&cmapTable[numCmaps].visual, visual, sizeof(Visual));
numCmaps++;
}
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/* The problem is that you have to have at least one DirectColor
colormap before you can set the gamma ramps or read the gamma
ramps. If the application has created a DirectColor window then the
cmapTable will have at least one colormap in it and everything is
cool. If not, then we just fail */
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int
X11_SetDisplayGammaRamp(_THIS, Uint16 * ramp)
{
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Display *display;
Colormap colormap;
XColor *colorcells;
int ncolors;
int i;
int j;
int rmax, gmax, bmax;
int rmul, gmul, bmul;
for (j = 0; j < numCmaps; j++) {
if (cmapTable[j].visual.class == DirectColor) {
display = cmapTable[j].display;
colormap = cmapTable[j].colormap;
ncolors = cmapTable[j].visual.map_entries;
colorcells = SDL_malloc(ncolors * sizeof(XColor));
if (NULL == colorcells) {
SDL_SetError("out of memory in X11_SetDisplayGammaRamp");
return -1;
}
rmax = cmapTable[j].cmap.red_max + 1;
gmax = cmapTable[j].cmap.blue_max + 1;
bmax = cmapTable[j].cmap.green_max + 1;
rmul = cmapTable[j].cmap.red_mult;
gmul = cmapTable[j].cmap.blue_mult;
bmul = cmapTable[j].cmap.green_mult;
/* build the color table pixel values */
for (i = 0; i < ncolors; i++) {
Uint32 red = (rmax * i) / ncolors;
Uint32 green = (gmax * i) / ncolors;
Uint32 blue = (bmax * i) / ncolors;
colorcells[i].pixel =
(red * rmul) | (green * gmul) | (blue * bmul);
colorcells[i].flags = DoRed | DoGreen | DoBlue;
colorcells[i].red = ramp[(0 * 256) + i];
colorcells[i].green = ramp[(1 * 256) + i];
colorcells[i].blue = ramp[(2 * 256) + i];
}
XStoreColors(display, colormap, colorcells, ncolors);
XFlush(display);
SDL_free(colorcells);
}
}
return 0;
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}
int
X11_GetDisplayGammaRamp(_THIS, Uint16 * ramp)
{
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Display *display;
Colormap colormap;
XColor *colorcells;
int ncolors;
int dc;
int i;
int rmax, gmax, bmax;
int rmul, gmul, bmul;
/* find the first DirectColor colormap and use it to get the gamma
ramp */
dc = -1;
for (i = 0; i < numCmaps; i++) {
if (cmapTable[i].visual.class == DirectColor) {
dc = i;
break;
}
}
if (dc < 0) {
return -1;
}
/* there is at least one DirectColor colormap in the cmapTable,
let's just get the entries from that colormap */
display = cmapTable[dc].display;
colormap = cmapTable[dc].colormap;
ncolors = cmapTable[dc].visual.map_entries;
colorcells = SDL_malloc(ncolors * sizeof(XColor));
if (NULL == colorcells) {
SDL_SetError("out of memory in X11_GetDisplayGammaRamp");
return -1;
}
rmax = cmapTable[dc].cmap.red_max + 1;
gmax = cmapTable[dc].cmap.blue_max + 1;
bmax = cmapTable[dc].cmap.green_max + 1;
rmul = cmapTable[dc].cmap.red_mult;
gmul = cmapTable[dc].cmap.blue_mult;
bmul = cmapTable[dc].cmap.green_mult;
/* build the color table pixel values */
for (i = 0; i < ncolors; i++) {
Uint32 red = (rmax * i) / ncolors;
Uint32 green = (gmax * i) / ncolors;
Uint32 blue = (bmax * i) / ncolors;
colorcells[i].pixel = (red * rmul) | (green * gmul) | (blue * bmul);
}
XQueryColors(display, colormap, colorcells, ncolors);
/* prepare the values to be returned. Note that SDL assumes that
gamma ramps are always 3 * 256 entries long with the red entries
in the first 256 elements, the green in the second 256 elements
and the blue in the last 256 elements */
for (i = 0; i < ncolors; i++) {
ramp[(0 * 256) + i] = colorcells[i].red;
ramp[(1 * 256) + i] = colorcells[i].green;
ramp[(2 * 256) + i] = colorcells[i].blue;
}
SDL_free(colorcells);
return 0;