/*** $Id: mybmp.c,v 1.10 2004/08/03 11:01:57 panweiguo Exp $**** Top-level bitmap file read/save function.**** Copyright (C) 2003 Feynman Software.** Copyright (C) 2000 ~ 2002 Wei Yongming.**** Current maintainer: Wei Yongming.**** Create date: 2001/12/17, derived from original ../newgdi/readbmp.c*//*** 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*/#include <stdio.h>#include <stdlib.h>#include <string.h>#include "common.h"#include "minigui.h"#include "gdi.h"#include "readbmp.h"/* * The idea comes from readbmp.c in Allegro by Shawn Hargreaves. */typedef struct{   char ext[8];   int (*load) (MG_RWops* fp, MYBITMAP *bmp, RGB *pal);   int (*save) (MG_RWops* fp, MYBITMAP *bmp, RGB *pal);   BOOL (*check) (MG_RWops* fp);} BITMAP_TYPE_INFO;#define MAX_BITMAP_TYPES   8static BITMAP_TYPE_INFO bitmap_types [MAX_BITMAP_TYPES] ={   { "bmp", __mg_load_bmp, #ifdef _SAVE_BITMAP__mg_save_bmp, __mg_check_bmp },#elseNULL, __mg_check_bmp },#endif#ifdef _LBM_FILE_SUPPORT   { "lbm", __mg_load_lbm, NULL, __mg_check_lbm },#else   { "",    NULL,     NULL, NULL },#endif#ifdef _PCX_FILE_SUPPORT   { "pcx", __mg_load_pcx, NULL, NULL },#else   { "",    NULL,     NULL, NULL },#endif#ifdef _TGA_FILE_SUPPORT   { "tga", __mg_load_tga, NULL, NULL },#else   { "",    NULL,     NULL, NULL },#endif#ifdef _GIF_FILE_SUPPORT   { "gif", __mg_load_gif, NULL, __mg_check_gif },#else   { "",    NULL,     NULL, NULL },#endif#ifdef _JPG_FILE_SUPPORT   { "jpg", __mg_load_jpg, NULL, __mg_check_jpg },#else   { "",    NULL,     NULL, NULL },#endif#ifdef _PNG_FILE_SUPPORT   { "png", __mg_load_png, NULL, __mg_check_png },#else   { "",    NULL,     NULL     },#endif   { "",    NULL,     NULL     },};/* RegisterBitmapFileType *  Informs Allegro of a new image file type, telling it how to load and *  save files of this format (either function may be NULL). */BOOL GUIAPI RegisterBitmapFileType (const char *ext,             int (*load) (MG_RWops* fp, MYBITMAP *bmp, RGB *pal),             int (*save) (MG_RWops* fp, MYBITMAP *bmp, RGB *pal),            BOOL (*check) (MG_RWops* fp)){    int i;    for (i = 0; i < MAX_BITMAP_TYPES; i++) {        if ((!bitmap_types[i].ext [0]) || (strcasecmp (bitmap_types[i].ext, ext) == 0)) {	        strncpy (bitmap_types[i].ext, ext, sizeof (bitmap_types[i].ext) - 1);	        bitmap_types[i].ext [sizeof (bitmap_types[i].ext) - 1] = 0;	        bitmap_types[i].load = load;	        bitmap_types[i].save = save;	        bitmap_types[i].check = check;	        return TRUE;      }   }    return FALSE;}#define PIX2BYTES(n)    (((n)+7)/8)/* * compute image line size and bytes per pixel * from bits per pixel and width */int bmpComputePitch(int bpp, Uint32 width, Uint32 *pitch, BOOL does_round){    int linesize;    int bytespp = 1;    if(bpp == 1)        linesize = PIX2BYTES (width);    else if(bpp <= 4)        linesize = PIX2BYTES (width << 2);    else if (bpp <= 8)        linesize = width;    else if(bpp <= 16) {        linesize = width * 2;        bytespp = 2;    } else if(bpp <= 24) {        linesize = width * 3;        bytespp = 3;    } else {        linesize = width * 4;        bytespp = 4;    }    /* rows are DWORD right aligned */    if (does_round)        *pitch = (linesize + 3) & -4;    else        *pitch = linesize;    return bytespp;}static const char* get_extension (const char* filename){    const char* ext;    ext = strrchr (filename, '.');    if (ext)        return ext + 1;    return NULL;}/* Function: int LoadMyBitmapEx (PMYBITMAP my_bmp, RGB* pal, MG_RWops* area, const char* ext); *      This function loads a bitmap from an image source and fills *      the specified MYBITMAP struct and returns the palette in pal if any. */int GUIAPI LoadMyBitmapEx (PMYBITMAP my_bmp, RGB* pal, MG_RWops* area, const char* ext){    int type;    int load_ret;    for (type = 0; type < MAX_BITMAP_TYPES; type++) {        if ((bitmap_types[type].ext [0]) && (strcasecmp (bitmap_types[type].ext, ext) == 0))            break;    }    if (type == MAX_BITMAP_TYPES) {        return ERR_BMP_UNKNOWN_TYPE;    }    if (bitmap_types[type].load == NULL) {        return ERR_BMP_CANT_READ;    }    my_bmp->flags = MYBMP_LOAD_NONE;    my_bmp->bits = NULL;    my_bmp->frames = 1;    my_bmp->depth = GetGDCapability (HDC_SCREEN, GDCAP_DEPTH);    if (my_bmp->depth <= 8)        GetPalette (HDC_SCREEN, 0, 256, (GAL_Color*)pal);#ifdef _GRAY_SCREEN    my_bmp->flags |= MYBMP_LOAD_GRAYSCALE;#endif    if ((load_ret = bitmap_types[type].load (area, my_bmp, pal)) != 0) {        free (my_bmp->bits);        return load_ret;    }    if (my_bmp->depth == 0) {        fprintf (stderr, "A bad implementation of load_bmp: %s.\n", ext);        return ERR_BMP_LOAD;    }    return ERR_BMP_OK;}int GUIAPI LoadMyBitmapFromFile (PMYBITMAP my_bmp, RGB* pal, const char* file_name){    MG_RWops* area;    const char* ext;    int ret_val;    if ((ext = get_extension (file_name)) == NULL)        return ERR_BMP_UNKNOWN_TYPE;    if (!(area = MGUI_RWFromFile (file_name, "rb"))) {        return ERR_BMP_FILEIO;    }    ret_val = LoadMyBitmapEx (my_bmp, pal, area, ext);    MGUI_RWclose (area);    return ret_val;}int GUIAPI LoadMyBitmapFromMem (PMYBITMAP my_bmp, RGB* pal, const void* mem, int size, const char* ext){    MG_RWops* area;    int ret_val;    if (!(area = MGUI_RWFromMem ((void*)mem, size))) {        return ERR_BMP_MEM;    }    ret_val = LoadMyBitmapEx (my_bmp, pal, area, ext);    MGUI_RWclose (area);    return ret_val;}void GUIAPI UnloadMyBitmap (PMYBITMAP my_bmp){    free (my_bmp->bits);}const char* GUIAPI CheckBitmapType (MG_RWops* fp){    int type;    int start_pos = MGUI_RWseek (fp, 0, SEEK_CUR);    for (type = 0; type < MAX_BITMAP_TYPES; type++) {        if (bitmap_types[type].check) {            if (bitmap_types[type].check (fp)) {                MGUI_RWseek (fp, start_pos, SEEK_SET);                return bitmap_types[type].ext;            }            else {                MGUI_RWseek (fp, start_pos, SEEK_SET);            }        }    }    return NULL;}#ifdef _SAVE_BITMAPint GUIAPI SaveMyBitmapToFile (PMYBITMAP my_bmp, RGB* pal, const char* spFileName){    MG_RWops* fp;    const char* ext;    int type;    int save_ret;    if ((ext = get_extension (spFileName)) == NULL)        return ERR_BMP_UNKNOWN_TYPE;    for (type = 0; type < MAX_BITMAP_TYPES; type++) {        if ((bitmap_types[type].ext [0]) && (strcasecmp (bitmap_types[type].ext, ext) == 0))            break;    }    if (type == MAX_BITMAP_TYPES)        return ERR_BMP_UNKNOWN_TYPE;    if (bitmap_types[type].save == NULL)        return ERR_BMP_CANT_SAVE;    if (!(fp = MGUI_RWFromFile (spFileName, "wb+"))) {#ifdef _DEBUG        fprintf (stderr, "Saving BMP file: fopen error.\n");#endif        return ERR_BMP_FILEIO;    }	save_ret = bitmap_types[type].save (fp, my_bmp, pal);    MGUI_RWclose (fp);    return save_ret;}#endif