bmp.c

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/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include "BLI_blenlib.h"

#include "imbuf.h"

#include "IMB_imbuf_types.h"
#include "IMB_imbuf.h"
#include "IMB_allocimbuf.h"
#include "IMB_filetype.h"

/* some code copied from article on microsoft.com, copied
  here for enhanced BMP support in the future
  http://www.microsoft.com/msj/defaultframe.asp?page=/msj/0197/mfcp1/mfcp1.htm&nav=/msj/0197/newnav.htm
*/

typedef struct BMPINFOHEADER{
    unsigned int    biSize;
    unsigned int    biWidth;
    unsigned int    biHeight;
    unsigned short  biPlanes;
    unsigned short  biBitCount;
    unsigned int    biCompression;
    unsigned int    biSizeImage;
    unsigned int    biXPelsPerMeter;
    unsigned int    biYPelsPerMeter;
    unsigned int    biClrUsed;
    unsigned int    biClrImportant;
} BMPINFOHEADER;

typedef struct BMPHEADER {
    unsigned short biType;
    unsigned int biSize;
    unsigned short biRes1;
    unsigned short biRes2;
    unsigned int biOffBits;
} BMPHEADER;

#define BMP_FILEHEADER_SIZE 14

static int checkbmp(unsigned char *mem)
{
    int ret_val = 0;
    BMPINFOHEADER bmi;
    unsigned int u;

    if (mem) {
        if ((mem[0] == 'B') && (mem[1] == 'M')) {
            /* skip fileheader */
            mem += BMP_FILEHEADER_SIZE;
        } else {
        }

        /* for systems where an int needs to be 4 bytes aligned */
        memcpy(&bmi, mem, sizeof(bmi));

        u = LITTLE_LONG(bmi.biSize);
        /* we only support uncompressed 24 or 32 bits images for now */
        if (u >= sizeof(BMPINFOHEADER)) {
            if ((bmi.biCompression == 0) && (bmi.biClrUsed == 0)) {
                u = LITTLE_SHORT(bmi.biBitCount);
                if (u >= 16) {
                    ret_val = 1;
                }
            }
        }
    }

    return(ret_val);
}

int imb_is_a_bmp(unsigned char *buf)
{
    return checkbmp(buf);
}

struct ImBuf *imb_bmp_decode(unsigned char *mem, size_t size, int flags)
{
    struct ImBuf *ibuf = NULL;
    BMPINFOHEADER bmi;
    int x, y, depth, skip, i;
    unsigned char *bmp, *rect;
    unsigned short col;
    
    (void)size; /* unused */

    if (checkbmp(mem) == 0) return(NULL);

    if ((mem[0] == 'B') && (mem[1] == 'M')) {
        /* skip fileheader */
        mem += BMP_FILEHEADER_SIZE;
    }

    /* for systems where an int needs to be 4 bytes aligned */
    memcpy(&bmi, mem, sizeof(bmi));

    skip = LITTLE_LONG(bmi.biSize);
    x = LITTLE_LONG(bmi.biWidth);
    y = LITTLE_LONG(bmi.biHeight);
    depth = LITTLE_SHORT(bmi.biBitCount);

    /* printf("skip: %d, x: %d y: %d, depth: %d (%x)\n", skip, x, y, 
        depth, bmi.biBitCount); */
    /* printf("skip: %d, x: %d y: %d, depth: %d (%x)\n", skip, x, y, 
        depth, bmi.biBitCount); */
    if (flags & IB_test) {
        ibuf = IMB_allocImBuf(x, y, depth, 0);
    } else {
        ibuf = IMB_allocImBuf(x, y, depth, IB_rect);
        bmp = mem + skip;
        rect = (unsigned char *) ibuf->rect;

        if (depth == 16) {
            for (i = x * y; i > 0; i--) {
                col = bmp[0] + (bmp[1] << 8);
                rect[0] = ((col >> 10) & 0x1f) << 3;
                rect[1] = ((col >>  5) & 0x1f) << 3;
                rect[2] = ((col >>  0) & 0x1f) << 3;
                
                rect[3] = 255;
                rect += 4; bmp += 2;
            }

        } else if (depth == 24) {
            for (i = y; i > 0; i--) {
                int j;
                for (j = x ; j > 0; j--) {
                    rect[0] = bmp[2];
                    rect[1] = bmp[1];
                    rect[2] = bmp[0];
                    
                    rect[3] = 255;
                    rect += 4; bmp += 3;
                }
                /* for 24-bit images, rows are padded to multiples of 4 */
                bmp += x % 4;   
            }
        } else if (depth == 32) {
            for (i = x * y; i > 0; i--) {
                rect[0] = bmp[2];
                rect[1] = bmp[1];
                rect[2] = bmp[0];
                rect[3] = bmp[3];
                rect += 4; bmp += 4;
            }
        }
    }

    if (ibuf) {
        ibuf->ftype = BMP;
        ibuf->profile = IB_PROFILE_SRGB;
    }
    
    return(ibuf);
}

/* Couple of helper functions for writing our data */
static int putIntLSB(unsigned int ui,FILE *ofile)
{
    putc((ui>>0)&0xFF,ofile); 
    putc((ui>>8)&0xFF,ofile); 
    putc((ui>>16)&0xFF,ofile); 
    return putc((ui>>24)&0xFF,ofile); 
}

static int putShortLSB(unsigned short us,FILE *ofile)
{
    putc((us>>0)&0xFF,ofile); 
    return putc((us>>8)&0xFF,ofile); 
} 

/* Found write info at http://users.ece.gatech.edu/~slabaugh/personal/c/bitmapUnix.c */
int imb_savebmp(struct ImBuf *ibuf, const char *name, int flags)
{
    BMPINFOHEADER infoheader;
    int bytesize, extrabytes, x, y, t, ptr;
    uchar *data;
    FILE *ofile;
    
    (void)flags; /* unused */

    extrabytes = (4 - ibuf->x*3 % 4) % 4;
    bytesize = (ibuf->x * 3 + extrabytes) * ibuf->y;

    data = (uchar *) ibuf->rect;
    ofile = fopen(name,"wb");
        if (!ofile) return 0;

    putShortLSB(19778,ofile); /* "BM" */
    putIntLSB(0,ofile); /* This can be 0 for BI_RGB bitmaps */
    putShortLSB(0,ofile); /* Res1 */
    putShortLSB(0,ofile); /* Res2 */
    putIntLSB(BMP_FILEHEADER_SIZE + sizeof(infoheader),ofile); 

    putIntLSB(sizeof(infoheader),ofile);
    putIntLSB(ibuf->x,ofile);
    putIntLSB(ibuf->y,ofile);
    putShortLSB(1,ofile);
    putShortLSB(24,ofile);
    putIntLSB(0,ofile);
    putIntLSB(bytesize + BMP_FILEHEADER_SIZE + sizeof(infoheader),ofile);
    putIntLSB(0,ofile);
    putIntLSB(0,ofile);
    putIntLSB(0,ofile);
    putIntLSB(0,ofile);

    /* Need to write out padded image data in bgr format */
    for (y=0;y<ibuf->y;y++) {
        for (x=0;x<ibuf->x;x++) {
            ptr=(x + y * ibuf->x) * 4;
            if (putc(data[ptr+2],ofile) == EOF) return 0;
            if (putc(data[ptr+1],ofile) == EOF) return 0;
            if (putc(data[ptr],ofile) == EOF) return 0;
        }
        /* add padding here */
        for (t=0;t<extrabytes;t++) if (putc(0,ofile) == EOF) return 0;
    }
    if (ofile) {
        fflush(ofile);
        fclose(ofile);
    }
    return 1;
}