pixels.c

linux下的图形界面开发minigui最新源代码

/*
**  $Id: pixels.c,v 1.4 2003/09/04 06:02:53 weiym Exp $
**  
**  Port to MiniGUI by Wei Yongming (2001/10/03).
**  Copyright (C) 2001 ~ 2002 Wei Yongming.
**  Copyright (C) 2003 Feynman Software.
**
**  SDL - Simple DirectMedia Layer
**  Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga
*/

/*
** 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; either version 2 of the License, or
** (at your option) any later version.
**
** 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, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

/* General (mostly internal) pixel/color manipulation routines for SDL */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "common.h"
#include "newgal.h"
#include "sysvideo.h"
#include "blit.h"
#include "pixels_c.h"
#include "RLEaccel_c.h"

/* Helper functions */
/*
 * Allocate a pixel format structure and fill it according to the given info.
 */
GAL_PixelFormat *GAL_AllocFormat(int bpp,
			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
{
	GAL_PixelFormat *format;
	Uint32 mask;

	/* Allocate an empty pixel format structure */
	format = malloc(sizeof(*format));
	if ( format == NULL ) {
		GAL_OutOfMemory();
		return(NULL);
	}
	memset(format, 0, sizeof(*format));
	format->alpha = GAL_ALPHA_OPAQUE;

	/* Set up the format */
	format->BitsPerPixel = bpp;
	format->BytesPerPixel = (bpp+7)/8;
    format->DitheredPalette = FALSE;
	switch (bpp) {
		case 1:
			/* Create the 2 color black-white palette */
			format->palette = (GAL_Palette *)malloc(
							sizeof(GAL_Palette));
			if ( format->palette == NULL ) {
				GAL_FreeFormat(format);
				GAL_OutOfMemory();
				return(NULL);
			}
			(format->palette)->ncolors = 2;
			(format->palette)->colors = (GAL_Color *)malloc(
				(format->palette)->ncolors*sizeof(GAL_Color));
			if ( (format->palette)->colors == NULL ) {
				GAL_FreeFormat(format);
				GAL_OutOfMemory();
				return(NULL);
			}
			format->palette->colors[0].r = 0xFF;
			format->palette->colors[0].g = 0xFF;
			format->palette->colors[0].b = 0xFF;
			format->palette->colors[1].r = 0x00;
			format->palette->colors[1].g = 0x00;
			format->palette->colors[1].b = 0x00;
			format->Rloss = 8;
			format->Gloss = 8;
			format->Bloss = 8;
			format->Aloss = 8;
			format->Rshift = 0;
			format->Gshift = 0;
			format->Bshift = 0;
			format->Ashift = 0;
			format->Rmask = 0;
			format->Gmask = 0;
			format->Bmask = 0;
			format->Amask = 0;
			break;

		case 4:
			/* Create the 16 color VGA palette */
			format->palette = (GAL_Palette *)malloc(
							sizeof(GAL_Palette));
			if ( format->palette == NULL ) {
				GAL_FreeFormat(format);
				GAL_OutOfMemory();
				return(NULL);
			}
			(format->palette)->ncolors = 16;
			(format->palette)->colors = (GAL_Color *)malloc(
				(format->palette)->ncolors*sizeof(GAL_Color));
			if ( (format->palette)->colors == NULL ) {
				GAL_FreeFormat(format);
				GAL_OutOfMemory();
				return(NULL);
			}
			/* Punt for now, will this ever be used? */
			memset((format->palette)->colors, 0,
				(format->palette)->ncolors*sizeof(GAL_Color));

			/* Palettized formats have no mask info */
			format->Rloss = 8;
			format->Gloss = 8;
			format->Bloss = 8;
			format->Aloss = 8;
			format->Rshift = 0;
			format->Gshift = 0;
			format->Bshift = 0;
			format->Ashift = 0;
			format->Rmask = 0;
			format->Gmask = 0;
			format->Bmask = 0;
			format->Amask = 0;
			break;

		case 8:
			/* Create an empty 256 color palette */
			format->palette = (GAL_Palette *)malloc(
							sizeof(GAL_Palette));
			if ( format->palette == NULL ) {
				GAL_FreeFormat(format);
				GAL_OutOfMemory();
				return(NULL);
			}
			(format->palette)->ncolors = 256;
			(format->palette)->colors = (GAL_Color *)malloc(
				(format->palette)->ncolors*sizeof(GAL_Color));
			if ( (format->palette)->colors == NULL ) {
				GAL_FreeFormat(format);
				GAL_OutOfMemory();
				return(NULL);
			}
			memset((format->palette)->colors, 0,
				(format->palette)->ncolors*sizeof(GAL_Color));

			/* Palettized formats have no mask info */
			format->Rloss = 8;
			format->Gloss = 8;
			format->Bloss = 8;
			format->Aloss = 8;
			format->Rshift = 0;
			format->Gshift = 0;
			format->Bshift = 0;
			format->Ashift = 0;
			format->Rmask = 0;
			format->Gmask = 0;
			format->Bmask = 0;
			format->Amask = 0;
			break;

		default:
			/* No palette, just packed pixel info */
			format->palette = NULL;
			format->Rshift = 0;
			format->Rloss = 8;
			if ( Rmask ) {
				for ( mask = Rmask; !(mask&0x01); mask >>= 1 )
					++format->Rshift;
				for ( ; (mask&0x01); mask >>= 1 )
					--format->Rloss;
			}
			format->Gshift = 0;
			format->Gloss = 8;
			if ( Gmask ) {
				for ( mask = Gmask; !(mask&0x01); mask >>= 1 )
					++format->Gshift;
				for ( ; (mask&0x01); mask >>= 1 )
					--format->Gloss;
			}
			format->Bshift = 0;
			format->Bloss = 8;
			if ( Bmask ) {
				for ( mask = Bmask; !(mask&0x01); mask >>= 1 )
					++format->Bshift;
				for ( ; (mask&0x01); mask >>= 1 )
					--format->Bloss;
			}
			format->Ashift = 0;
			format->Aloss = 8;
			if ( Amask ) {
				for ( mask = Amask; !(mask&0x01); mask >>= 1 )
					++format->Ashift;
				for ( ; (mask&0x01); mask >>= 1 )
					--format->Aloss;
			}
			format->Rmask = Rmask;
			format->Gmask = Gmask;
			format->Bmask = Bmask;
			format->Amask = Amask;
			break;
	}
	/* Calculate some standard bitmasks, if necessary 
	 * Note:  This could conflict with an alpha mask, if given.
	 */
	if ( (bpp > 8) && !format->Rmask && !format->Gmask && !format->Bmask ) {
		/* R-G-B */
		if ( bpp > 24 )
			bpp = 24;
		format->Rloss = 8-(bpp/3);
		format->Gloss = 8-(bpp/3)-(bpp%3);
		format->Bloss = 8-(bpp/3);
		format->Rshift = ((bpp/3)+(bpp%3))+(bpp/3);
		format->Gshift = (bpp/3);
		format->Bshift = 0;
		format->Rmask = ((0xFF>>format->Rloss)<<format->Rshift);
		format->Gmask = ((0xFF>>format->Gloss)<<format->Gshift);
		format->Bmask = ((0xFF>>format->Bloss)<<format->Bshift);
	}
	return(format);
}
GAL_PixelFormat *GAL_ReallocFormat(GAL_Surface *surface, int bpp,
			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
{
	if ( surface->format ) {
		GAL_FreeFormat(surface->format);
		GAL_FormatChanged(surface);
	}
	surface->format = GAL_AllocFormat(bpp, Rmask, Gmask, Bmask, Amask);
	return surface->format;
}

/*
 * Change any previous mappings from/to the new surface format
 */
void GAL_FormatChanged(GAL_Surface *surface)
{
	surface->format_version++;
	GAL_InvalidateMap(surface->map);
}
/*
 * Free a previously allocated format structure
 */
void GAL_FreeFormat(GAL_PixelFormat *format)
{
	if ( format ) {
		if ( format->palette ) {
			if ( format->palette->colors ) {
				free(format->palette->colors);
			}
			free(format->palette);
		}
		free(format);
	}
}
/*
 * Calculate an 8-bit (3 red, 3 green, 2 blue) dithered palette of colors
 */
void GAL_DitherColors(GAL_Color *colors, int bpp)
{
	int i;
	if(bpp != 8)
		return;		/* only 8bpp supported right now */

	for(i = 0; i < 256; i++) {
		int r, g, b;
		/* map each bit field to the full [0, 255] interval,
		   so 0 is mapped to (0, 0, 0) and 255 to (255, 255, 255) */
		r = i & 0xe0;
		r |= r >> 3 | r >> 6;
		colors[i].r = r;
		g = (i << 3) & 0xe0;
		g |= g >> 3 | g >> 6;
		colors[i].g = g;
		b = i & 0x3;
		b |= b << 2;
		b |= b << 4;
		colors[i].b = b;
	}
}

Uint8 GAL_FindDitheredColor (int bpp, Uint8 r, Uint8 g, Uint8 b)
{
	if (bpp != 8)
		return 0;		/* only 8bpp supported right now */

    r &= 0xe0;
    g &= 0xe0; g >>= 3;
    b &= 0xc0; b >>= 6;

    return r | g | b;
}

/* 
 * Calculate the pad-aligned scanline width of a surface
 */
Uint16 GAL_CalculatePitch(GAL_Surface *surface)
{
	Uint16 pitch;

	/* Box should be 4-byte aligned for speed */
	pitch = surface->w * surface->format->BytesPerPixel;
	switch (surface->format->BitsPerPixel) {
		case 1:
			pitch = (pitch+7)/8;
			break;
		case 4:
			pitch = (pitch+1)/2;
			break;
		default: