src/video/SDL_bmp.c
author Sam Lantinga <slouken@libsdl.org>
Tue, 26 May 2015 06:27:46 -0700
changeset 9619 b94b6d0bff0f
parent 9563 537881242756
child 9998 f67cf37e9cd4
permissions -rw-r--r--
Updated the copyright year to 2015
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     1
/*
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  Simple DirectMedia Layer
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  Copyright (C) 1997-2015 Sam Lantinga <slouken@libsdl.org>
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  This software is provided 'as-is', without any express or implied
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  warranty.  In no event will the authors be held liable for any damages
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  arising from the use of this software.
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  Permission is granted to anyone to use this software for any purpose,
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  including commercial applications, and to alter it and redistribute it
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  freely, subject to the following restrictions:
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  1. The origin of this software must not be misrepresented; you must not
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     claim that you wrote the original software. If you use this software
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     in a product, an acknowledgment in the product documentation would be
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     appreciated but is not required.
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  2. Altered source versions must be plainly marked as such, and must not be
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     misrepresented as being the original software.
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  3. This notice may not be removed or altered from any source distribution.
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*/
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#include "../SDL_internal.h"
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/*
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   Code to load and save surfaces in Windows BMP format.
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   Why support BMP format?  Well, it's a native format for Windows, and
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   most image processing programs can read and write it.  It would be nice
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   to be able to have at least one image format that we can natively load
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   and save, and since PNG is so complex that it would bloat the library,
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   BMP is a good alternative.
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   This code currently supports Win32 DIBs in uncompressed 8 and 24 bpp.
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*/
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#include "SDL_video.h"
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#include "SDL_assert.h"
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#include "SDL_endian.h"
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#include "SDL_pixels_c.h"
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#define SAVE_32BIT_BMP
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/* Compression encodings for BMP files */
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#ifndef BI_RGB
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#define BI_RGB      0
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#define BI_RLE8     1
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#define BI_RLE4     2
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#define BI_BITFIELDS    3
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#endif
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    50
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static void CorrectAlphaChannel(SDL_Surface *surface)
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{
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    /* Check to see if there is any alpha channel data */
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    SDL_bool hasAlpha = SDL_FALSE;
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#if SDL_BYTEORDER == SDL_BIG_ENDIAN
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    int alphaChannelOffset = 0;
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#else
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    int alphaChannelOffset = 3;
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#endif
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    Uint8 *alpha = ((Uint8*)surface->pixels) + alphaChannelOffset;
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    Uint8 *end = alpha + surface->h * surface->pitch;
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    while (alpha < end) {
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        if (*alpha != 0) {
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            hasAlpha = SDL_TRUE;
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            break;
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        }
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        alpha += 4;
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    }
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    if (!hasAlpha) {
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        alpha = ((Uint8*)surface->pixels) + alphaChannelOffset;
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        while (alpha < end) {
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            *alpha = SDL_ALPHA_OPAQUE;
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            alpha += 4;
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        }
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    }
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}
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SDL_Surface *
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SDL_LoadBMP_RW(SDL_RWops * src, int freesrc)
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{
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    SDL_bool was_error;
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    Sint64 fp_offset = 0;
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    int bmpPitch;
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    int i, pad;
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    SDL_Surface *surface;
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    Uint32 Rmask = 0;
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    Uint32 Gmask = 0;
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    Uint32 Bmask = 0;
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    Uint32 Amask = 0;
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    SDL_Palette *palette;
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    Uint8 *bits;
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    Uint8 *top, *end;
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    SDL_bool topDown;
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    int ExpandBMP;
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    SDL_bool haveRGBMasks = SDL_FALSE;
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    SDL_bool haveAlphaMask = SDL_FALSE;
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    SDL_bool correctAlpha = SDL_FALSE;
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    /* The Win32 BMP file header (14 bytes) */
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    char magic[2];
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    /* Uint32 bfSize = 0; */
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    /* Uint16 bfReserved1 = 0; */
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    /* Uint16 bfReserved2 = 0; */
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    Uint32 bfOffBits = 0;
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    /* The Win32 BITMAPINFOHEADER struct (40 bytes) */
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    Uint32 biSize = 0;
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    Sint32 biWidth = 0;
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    Sint32 biHeight = 0;
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    /* Uint16 biPlanes = 0; */
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    Uint16 biBitCount = 0;
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    Uint32 biCompression = 0;
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    /* Uint32 biSizeImage = 0; */
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    /* Sint32 biXPelsPerMeter = 0; */
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    /* Sint32 biYPelsPerMeter = 0; */
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    Uint32 biClrUsed = 0;
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    /* Uint32 biClrImportant = 0; */
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    /* Make sure we are passed a valid data source */
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    surface = NULL;
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    was_error = SDL_FALSE;
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    if (src == NULL) {
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        was_error = SDL_TRUE;
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        goto done;
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    }
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    /* Read in the BMP file header */
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    fp_offset = SDL_RWtell(src);
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    SDL_ClearError();
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    if (SDL_RWread(src, magic, 1, 2) != 2) {
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        SDL_Error(SDL_EFREAD);
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        was_error = SDL_TRUE;
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        goto done;
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    }
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    if (SDL_strncmp(magic, "BM", 2) != 0) {
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        SDL_SetError("File is not a Windows BMP file");
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        was_error = SDL_TRUE;
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        goto done;
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    }
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    /* bfSize = */ SDL_ReadLE32(src);
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    /* bfReserved1 = */ SDL_ReadLE16(src);
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    /* bfReserved2 = */ SDL_ReadLE16(src);
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    bfOffBits = SDL_ReadLE32(src);
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    /* Read the Win32 BITMAPINFOHEADER */
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    biSize = SDL_ReadLE32(src);
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    if (biSize == 12) {   /* really old BITMAPCOREHEADER */
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        biWidth = (Uint32) SDL_ReadLE16(src);
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        biHeight = (Uint32) SDL_ReadLE16(src);
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        /* biPlanes = */ SDL_ReadLE16(src);
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        biBitCount = SDL_ReadLE16(src);
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        biCompression = BI_RGB;
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    } else if (biSize >= 40) {  /* some version of BITMAPINFOHEADER */
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        Uint32 headerSize;
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        biWidth = SDL_ReadLE32(src);
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        biHeight = SDL_ReadLE32(src);
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        /* biPlanes = */ SDL_ReadLE16(src);
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        biBitCount = SDL_ReadLE16(src);
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        biCompression = SDL_ReadLE32(src);
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        /* biSizeImage = */ SDL_ReadLE32(src);
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        /* biXPelsPerMeter = */ SDL_ReadLE32(src);
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        /* biYPelsPerMeter = */ SDL_ReadLE32(src);
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        biClrUsed = SDL_ReadLE32(src);
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        /* biClrImportant = */ SDL_ReadLE32(src);
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        /* 64 == BITMAPCOREHEADER2, an incompatible OS/2 2.x extension. Skip this stuff for now. */
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        if (biSize == 64) {
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            /* ignore these extra fields. */
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            if (biCompression == BI_BITFIELDS) {
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                /* this value is actually huffman compression in this variant. */
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                SDL_SetError("Compressed BMP files not supported");
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                was_error = SDL_TRUE;
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                goto done;
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            }
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        } else {
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            /* This is complicated. If compression is BI_BITFIELDS, then
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               we have 3 DWORDS that specify the RGB masks. This is either
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               stored here in an BITMAPV2INFOHEADER (which only differs in
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               that it adds these RGB masks) and biSize >= 52, or we've got
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               these masks stored in the exact same place, but strictly
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               speaking, this is the bmiColors field in BITMAPINFO immediately
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               following the legacy v1 info header, just past biSize. */
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            if (biCompression == BI_BITFIELDS) {
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                haveRGBMasks = SDL_TRUE;
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                Rmask = SDL_ReadLE32(src);
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                Gmask = SDL_ReadLE32(src);
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                Bmask = SDL_ReadLE32(src);
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                /* ...v3 adds an alpha mask. */
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                if (biSize >= 56) {  /* BITMAPV3INFOHEADER; adds alpha mask */
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                    haveAlphaMask = SDL_TRUE;
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                    Amask = SDL_ReadLE32(src);
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                }
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            } else {
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                /* the mask fields are ignored for v2+ headers if not BI_BITFIELD. */
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                if (biSize >= 52) {  /* BITMAPV2INFOHEADER; adds RGB masks */
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                    /*Rmask = */ SDL_ReadLE32(src);
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                    /*Gmask = */ SDL_ReadLE32(src);
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                    /*Bmask = */ SDL_ReadLE32(src);
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                }
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                if (biSize >= 56) {  /* BITMAPV3INFOHEADER; adds alpha mask */
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                    /*Amask = */ SDL_ReadLE32(src);
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                }
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            }
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            /* Insert other fields here; Wikipedia and MSDN say we're up to
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               v5 of this header, but we ignore those for now (they add gamma,
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               color spaces, etc). Ignoring the weird OS/2 2.x format, we
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               currently parse up to v3 correctly (hopefully!). */
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        }
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        /* skip any header bytes we didn't handle... */
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        headerSize = (Uint32) (SDL_RWtell(src) - (fp_offset + 14));
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        if (biSize > headerSize) {
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            SDL_RWseek(src, (biSize - headerSize), RW_SEEK_CUR);
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        }
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    }
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    if (biHeight < 0) {
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        topDown = SDL_TRUE;
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        biHeight = -biHeight;
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    } else {
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        topDown = SDL_FALSE;
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   225
    }
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    /* Check for read error */
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    if (SDL_strcmp(SDL_GetError(), "") != 0) {
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        was_error = SDL_TRUE;
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   230
        goto done;
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   231
    }
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   232
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   233
    /* Expand 1 and 4 bit bitmaps to 8 bits per pixel */
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   234
    switch (biBitCount) {
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    case 1:
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   236
    case 4:
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        ExpandBMP = biBitCount;
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   238
        biBitCount = 8;
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   239
        break;
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   240
    default:
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   241
        ExpandBMP = 0;
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   242
        break;
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   243
    }
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   244
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   245
    /* We don't support any BMP compression right now */
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   246
    switch (biCompression) {
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   247
    case BI_RGB:
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   248
        /* If there are no masks, use the defaults */
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   249
        SDL_assert(!haveRGBMasks);
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   250
        SDL_assert(!haveAlphaMask);
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   251
        /* Default values for the BMP format */
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   252
        switch (biBitCount) {
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   253
        case 15:
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   254
        case 16:
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   255
            Rmask = 0x7C00;
icculus@9126
   256
            Gmask = 0x03E0;
icculus@9126
   257
            Bmask = 0x001F;
icculus@9126
   258
            break;
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   259
        case 24:
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   260
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
icculus@9126
   261
            Rmask = 0x000000FF;
icculus@9126
   262
            Gmask = 0x0000FF00;
icculus@9126
   263
            Bmask = 0x00FF0000;
icculus@9126
   264
#else
icculus@9126
   265
            Rmask = 0x00FF0000;
icculus@9126
   266
            Gmask = 0x0000FF00;
icculus@9126
   267
            Bmask = 0x000000FF;
icculus@9126
   268
#endif
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   269
            break;
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   270
        case 32:
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   271
            /* We don't know if this has alpha channel or not */
icculus@9126
   272
            correctAlpha = SDL_TRUE;
icculus@9126
   273
            Amask = 0xFF000000;
icculus@9126
   274
            Rmask = 0x00FF0000;
icculus@9126
   275
            Gmask = 0x0000FF00;
icculus@9126
   276
            Bmask = 0x000000FF;
slouken@1895
   277
            break;
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   278
        default:
slouken@1895
   279
            break;
slouken@1895
   280
        }
slouken@1895
   281
        break;
icculus@9126
   282
icculus@9126
   283
    case BI_BITFIELDS:
icculus@9126
   284
        break;  /* we handled this in the info header. */
icculus@9126
   285
slouken@1895
   286
    default:
slouken@1895
   287
        SDL_SetError("Compressed BMP files not supported");
slouken@3310
   288
        was_error = SDL_TRUE;
slouken@1895
   289
        goto done;
slouken@1895
   290
    }
slouken@0
   291
slouken@1895
   292
    /* Create a compatible surface, note that the colors are RGB ordered */
slouken@1895
   293
    surface =
slouken@1895
   294
        SDL_CreateRGBSurface(0, biWidth, biHeight, biBitCount, Rmask, Gmask,
slouken@3497
   295
                             Bmask, Amask);
slouken@1895
   296
    if (surface == NULL) {
slouken@3310
   297
        was_error = SDL_TRUE;
slouken@1895
   298
        goto done;
slouken@1895
   299
    }
slouken@0
   300
slouken@1895
   301
    /* Load the palette, if any */
slouken@1895
   302
    palette = (surface->format)->palette;
slouken@1895
   303
    if (palette) {
icculus@8675
   304
        SDL_assert(biBitCount <= 8);
slouken@1895
   305
        if (biClrUsed == 0) {
slouken@1895
   306
            biClrUsed = 1 << biBitCount;
slouken@1895
   307
        }
slouken@2920
   308
        if ((int) biClrUsed > palette->ncolors) {
philipp@9334
   309
            SDL_Color *colors;
philipp@9336
   310
            int ncolors = biClrUsed;
philipp@9334
   311
            colors =
slouken@2851
   312
                (SDL_Color *) SDL_realloc(palette->colors,
philipp@9336
   313
                                          ncolors *
slouken@2851
   314
                                          sizeof(*palette->colors));
philipp@9334
   315
            if (!colors) {
slouken@2851
   316
                SDL_OutOfMemory();
slouken@3310
   317
                was_error = SDL_TRUE;
slouken@2851
   318
                goto done;
slouken@2851
   319
            }
philipp@9336
   320
            palette->ncolors = ncolors;
philipp@9334
   321
            palette->colors = colors;
slouken@2920
   322
        } else if ((int) biClrUsed < palette->ncolors) {
slouken@2851
   323
            palette->ncolors = biClrUsed;
slouken@2851
   324
        }
slouken@1895
   325
        if (biSize == 12) {
slouken@1895
   326
            for (i = 0; i < (int) biClrUsed; ++i) {
slouken@1895
   327
                SDL_RWread(src, &palette->colors[i].b, 1, 1);
slouken@1895
   328
                SDL_RWread(src, &palette->colors[i].g, 1, 1);
slouken@1895
   329
                SDL_RWread(src, &palette->colors[i].r, 1, 1);
slouken@7024
   330
                palette->colors[i].a = SDL_ALPHA_OPAQUE;
slouken@1895
   331
            }
slouken@1895
   332
        } else {
slouken@1895
   333
            for (i = 0; i < (int) biClrUsed; ++i) {
slouken@1895
   334
                SDL_RWread(src, &palette->colors[i].b, 1, 1);
slouken@1895
   335
                SDL_RWread(src, &palette->colors[i].g, 1, 1);
slouken@1895
   336
                SDL_RWread(src, &palette->colors[i].r, 1, 1);
slouken@7024
   337
                SDL_RWread(src, &palette->colors[i].a, 1, 1);
slouken@7068
   338
slouken@7068
   339
                /* According to Microsoft documentation, the fourth element
slouken@7068
   340
                   is reserved and must be zero, so we shouldn't treat it as
slouken@7068
   341
                   alpha.
slouken@7068
   342
                */
slouken@7068
   343
                palette->colors[i].a = SDL_ALPHA_OPAQUE;
slouken@1895
   344
            }
slouken@1895
   345
        }
slouken@1895
   346
    }
slouken@0
   347
slouken@1895
   348
    /* Read the surface pixels.  Note that the bmp image is upside down */
slouken@1895
   349
    if (SDL_RWseek(src, fp_offset + bfOffBits, RW_SEEK_SET) < 0) {
slouken@1895
   350
        SDL_Error(SDL_EFSEEK);
slouken@3310
   351
        was_error = SDL_TRUE;
slouken@1895
   352
        goto done;
slouken@1895
   353
    }
slouken@3310
   354
    top = (Uint8 *)surface->pixels;
slouken@3310
   355
    end = (Uint8 *)surface->pixels+(surface->h*surface->pitch);
slouken@1895
   356
    switch (ExpandBMP) {
slouken@1895
   357
    case 1:
slouken@1895
   358
        bmpPitch = (biWidth + 7) >> 3;
slouken@1895
   359
        pad = (((bmpPitch) % 4) ? (4 - ((bmpPitch) % 4)) : 0);
slouken@1895
   360
        break;
slouken@1895
   361
    case 4:
slouken@1895
   362
        bmpPitch = (biWidth + 1) >> 1;
slouken@1895
   363
        pad = (((bmpPitch) % 4) ? (4 - ((bmpPitch) % 4)) : 0);
slouken@1895
   364
        break;
slouken@1895
   365
    default:
slouken@1895
   366
        pad = ((surface->pitch % 4) ? (4 - (surface->pitch % 4)) : 0);
slouken@1895
   367
        break;
slouken@1895
   368
    }
slouken@3310
   369
    if (topDown) {
slouken@3310
   370
        bits = top;
slouken@3310
   371
    } else {
slouken@3310
   372
        bits = end - surface->pitch;
slouken@3310
   373
    }
slouken@3310
   374
    while (bits >= top && bits < end) {
slouken@1895
   375
        switch (ExpandBMP) {
slouken@1895
   376
        case 1:
slouken@3310
   377
        case 4:{
slouken@1895
   378
                Uint8 pixel = 0;
slouken@1895
   379
                int shift = (8 - ExpandBMP);
slouken@1895
   380
                for (i = 0; i < surface->w; ++i) {
slouken@1895
   381
                    if (i % (8 / ExpandBMP) == 0) {
slouken@1895
   382
                        if (!SDL_RWread(src, &pixel, 1, 1)) {
slouken@1895
   383
                            SDL_SetError("Error reading from BMP");
slouken@3310
   384
                            was_error = SDL_TRUE;
slouken@1895
   385
                            goto done;
slouken@1895
   386
                        }
slouken@1895
   387
                    }
slouken@1895
   388
                    *(bits + i) = (pixel >> shift);
slouken@1895
   389
                    pixel <<= ExpandBMP;
slouken@1895
   390
                }
slouken@1895
   391
            }
slouken@1895
   392
            break;
slouken@0
   393
slouken@1895
   394
        default:
slouken@1895
   395
            if (SDL_RWread(src, bits, 1, surface->pitch)
slouken@1895
   396
                != surface->pitch) {
slouken@1895
   397
                SDL_Error(SDL_EFREAD);
slouken@3310
   398
                was_error = SDL_TRUE;
slouken@1895
   399
                goto done;
slouken@1895
   400
            }
slouken@0
   401
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
slouken@1895
   402
            /* Byte-swap the pixels if needed. Note that the 24bpp
slouken@1895
   403
               case has already been taken care of above. */
slouken@1895
   404
            switch (biBitCount) {
slouken@1895
   405
            case 15:
slouken@3310
   406
            case 16:{
slouken@1895
   407
                    Uint16 *pix = (Uint16 *) bits;
slouken@1895
   408
                    for (i = 0; i < surface->w; i++)
slouken@1895
   409
                        pix[i] = SDL_Swap16(pix[i]);
slouken@1895
   410
                    break;
slouken@1895
   411
                }
slouken@0
   412
slouken@3310
   413
            case 32:{
slouken@1895
   414
                    Uint32 *pix = (Uint32 *) bits;
slouken@1895
   415
                    for (i = 0; i < surface->w; i++)
slouken@1895
   416
                        pix[i] = SDL_Swap32(pix[i]);
slouken@1895
   417
                    break;
slouken@1895
   418
                }
slouken@1895
   419
            }
slouken@0
   420
#endif
slouken@1895
   421
            break;
slouken@1895
   422
        }
slouken@1895
   423
        /* Skip padding bytes, ugh */
slouken@1895
   424
        if (pad) {
slouken@1895
   425
            Uint8 padbyte;
slouken@1895
   426
            for (i = 0; i < pad; ++i) {
slouken@1895
   427
                SDL_RWread(src, &padbyte, 1, 1);
slouken@1895
   428
            }
slouken@1895
   429
        }
slouken@3310
   430
        if (topDown) {
slouken@3310
   431
            bits += surface->pitch;
slouken@3310
   432
        } else {
slouken@3310
   433
            bits -= surface->pitch;
slouken@3310
   434
        }
slouken@1895
   435
    }
slouken@7378
   436
    if (correctAlpha) {
slouken@7378
   437
        CorrectAlphaChannel(surface);
slouken@7378
   438
    }
slouken@1895
   439
  done:
slouken@1895
   440
    if (was_error) {
slouken@1895
   441
        if (src) {
slouken@1895
   442
            SDL_RWseek(src, fp_offset, RW_SEEK_SET);
slouken@1895
   443
        }
slouken@7720
   444
        SDL_FreeSurface(surface);
slouken@1895
   445
        surface = NULL;
slouken@1895
   446
    }
slouken@1895
   447
    if (freesrc && src) {
slouken@1895
   448
        SDL_RWclose(src);
slouken@1895
   449
    }
slouken@1895
   450
    return (surface);
slouken@0
   451
}
slouken@0
   452
slouken@1895
   453
int
slouken@1895
   454
SDL_SaveBMP_RW(SDL_Surface * saveme, SDL_RWops * dst, int freedst)
slouken@0
   455
{
slouken@6666
   456
    Sint64 fp_offset;
slouken@1895
   457
    int i, pad;
slouken@1895
   458
    SDL_Surface *surface;
slouken@1895
   459
    Uint8 *bits;
slouken@0
   460
slouken@1895
   461
    /* The Win32 BMP file header (14 bytes) */
slouken@1895
   462
    char magic[2] = { 'B', 'M' };
slouken@1895
   463
    Uint32 bfSize;
slouken@1895
   464
    Uint16 bfReserved1;
slouken@1895
   465
    Uint16 bfReserved2;
slouken@1895
   466
    Uint32 bfOffBits;
slouken@0
   467
slouken@1895
   468
    /* The Win32 BITMAPINFOHEADER struct (40 bytes) */
slouken@1895
   469
    Uint32 biSize;
slouken@1895
   470
    Sint32 biWidth;
slouken@1895
   471
    Sint32 biHeight;
slouken@1895
   472
    Uint16 biPlanes;
slouken@1895
   473
    Uint16 biBitCount;
slouken@1895
   474
    Uint32 biCompression;
slouken@1895
   475
    Uint32 biSizeImage;
slouken@1895
   476
    Sint32 biXPelsPerMeter;
slouken@1895
   477
    Sint32 biYPelsPerMeter;
slouken@1895
   478
    Uint32 biClrUsed;
slouken@1895
   479
    Uint32 biClrImportant;
slouken@0
   480
slouken@1895
   481
    /* Make sure we have somewhere to save */
slouken@1895
   482
    surface = NULL;
slouken@1895
   483
    if (dst) {
slouken@2969
   484
        SDL_bool save32bit = SDL_FALSE;
slouken@2969
   485
#ifdef SAVE_32BIT_BMP
slouken@2969
   486
        /* We can save alpha information in a 32-bit BMP */
slouken@2969
   487
        if (saveme->map->info.flags & SDL_COPY_COLORKEY ||
slouken@2969
   488
            saveme->format->Amask) {
slouken@2969
   489
            save32bit = SDL_TRUE;
slouken@2969
   490
        }
slouken@2969
   491
#endif /* SAVE_32BIT_BMP */
slouken@2969
   492
slouken@2969
   493
        if (saveme->format->palette && !save32bit) {
slouken@1895
   494
            if (saveme->format->BitsPerPixel == 8) {
slouken@1895
   495
                surface = saveme;
slouken@1895
   496
            } else {
slouken@1895
   497
                SDL_SetError("%d bpp BMP files not supported",
slouken@1895
   498
                             saveme->format->BitsPerPixel);
slouken@1895
   499
            }
slouken@1895
   500
        } else if ((saveme->format->BitsPerPixel == 24) &&
slouken@0
   501
#if SDL_BYTEORDER == SDL_LIL_ENDIAN
slouken@1895
   502
                   (saveme->format->Rmask == 0x00FF0000) &&
slouken@1895
   503
                   (saveme->format->Gmask == 0x0000FF00) &&
slouken@1895
   504
                   (saveme->format->Bmask == 0x000000FF)
slouken@0
   505
#else
slouken@1895
   506
                   (saveme->format->Rmask == 0x000000FF) &&
slouken@1895
   507
                   (saveme->format->Gmask == 0x0000FF00) &&
slouken@1895
   508
                   (saveme->format->Bmask == 0x00FF0000)
slouken@0
   509
#endif
slouken@1895
   510
            ) {
slouken@1895
   511
            surface = saveme;
slouken@1895
   512
        } else {
slouken@2967
   513
            SDL_PixelFormat format;
slouken@0
   514
slouken@2969
   515
            /* If the surface has a colorkey or alpha channel we'll save a
slouken@2969
   516
               32-bit BMP with alpha channel, otherwise save a 24-bit BMP. */
slouken@2969
   517
            if (save32bit) {
slouken@7191
   518
                SDL_InitFormat(&format,
slouken@5288
   519
#if SDL_BYTEORDER == SDL_LIL_ENDIAN
slouken@5288
   520
                               SDL_PIXELFORMAT_ARGB8888
slouken@5288
   521
#else
slouken@5288
   522
                               SDL_PIXELFORMAT_BGRA8888
slouken@5288
   523
#endif
slouken@5288
   524
                               );
slouken@2969
   525
            } else {
slouken@5288
   526
                SDL_InitFormat(&format, SDL_PIXELFORMAT_BGR24);
slouken@2969
   527
            }
slouken@2967
   528
            surface = SDL_ConvertSurface(saveme, &format, 0);
slouken@2967
   529
            if (!surface) {
slouken@2990
   530
                SDL_SetError("Couldn't convert image to %d bpp",
slouken@2990
   531
                             format.BitsPerPixel);
slouken@1895
   532
            }
slouken@1895
   533
        }
philipp@9563
   534
    } else {
philipp@9563
   535
        /* Set no error here because it may overwrite a more useful message from
philipp@9563
   536
           SDL_RWFromFile() if SDL_SaveBMP_RW() is called from SDL_SaveBMP(). */
philipp@9563
   537
        return -1;
slouken@1895
   538
    }
slouken@0
   539
slouken@1895
   540
    if (surface && (SDL_LockSurface(surface) == 0)) {
slouken@1895
   541
        const int bw = surface->w * surface->format->BytesPerPixel;
slouken@1012
   542
slouken@1895
   543
        /* Set the BMP file header values */
slouken@1895
   544
        bfSize = 0;             /* We'll write this when we're done */
slouken@1895
   545
        bfReserved1 = 0;
slouken@1895
   546
        bfReserved2 = 0;
slouken@1895
   547
        bfOffBits = 0;          /* We'll write this when we're done */
slouken@0
   548
slouken@1895
   549
        /* Write the BMP file header values */
slouken@1895
   550
        fp_offset = SDL_RWtell(dst);
slouken@1895
   551
        SDL_ClearError();
slouken@1895
   552
        SDL_RWwrite(dst, magic, 2, 1);
slouken@1895
   553
        SDL_WriteLE32(dst, bfSize);
slouken@1895
   554
        SDL_WriteLE16(dst, bfReserved1);
slouken@1895
   555
        SDL_WriteLE16(dst, bfReserved2);
slouken@1895
   556
        SDL_WriteLE32(dst, bfOffBits);
slouken@0
   557
slouken@1895
   558
        /* Set the BMP info values */
slouken@1895
   559
        biSize = 40;
slouken@1895
   560
        biWidth = surface->w;
slouken@1895
   561
        biHeight = surface->h;
slouken@1895
   562
        biPlanes = 1;
slouken@1895
   563
        biBitCount = surface->format->BitsPerPixel;
slouken@1895
   564
        biCompression = BI_RGB;
slouken@1895
   565
        biSizeImage = surface->h * surface->pitch;
slouken@1895
   566
        biXPelsPerMeter = 0;
slouken@1895
   567
        biYPelsPerMeter = 0;
slouken@1895
   568
        if (surface->format->palette) {
slouken@1895
   569
            biClrUsed = surface->format->palette->ncolors;
slouken@1895
   570
        } else {
slouken@1895
   571
            biClrUsed = 0;
slouken@1895
   572
        }
slouken@1895
   573
        biClrImportant = 0;
slouken@0
   574
slouken@1895
   575
        /* Write the BMP info values */
slouken@1895
   576
        SDL_WriteLE32(dst, biSize);
slouken@1895
   577
        SDL_WriteLE32(dst, biWidth);
slouken@1895
   578
        SDL_WriteLE32(dst, biHeight);
slouken@1895
   579
        SDL_WriteLE16(dst, biPlanes);
slouken@1895
   580
        SDL_WriteLE16(dst, biBitCount);
slouken@1895
   581
        SDL_WriteLE32(dst, biCompression);
slouken@1895
   582
        SDL_WriteLE32(dst, biSizeImage);
slouken@1895
   583
        SDL_WriteLE32(dst, biXPelsPerMeter);
slouken@1895
   584
        SDL_WriteLE32(dst, biYPelsPerMeter);
slouken@1895
   585
        SDL_WriteLE32(dst, biClrUsed);
slouken@1895
   586
        SDL_WriteLE32(dst, biClrImportant);
slouken@0
   587
slouken@1895
   588
        /* Write the palette (in BGR color order) */
slouken@1895
   589
        if (surface->format->palette) {
slouken@1895
   590
            SDL_Color *colors;
slouken@1895
   591
            int ncolors;
slouken@0
   592
slouken@1895
   593
            colors = surface->format->palette->colors;
slouken@1895
   594
            ncolors = surface->format->palette->ncolors;
slouken@1895
   595
            for (i = 0; i < ncolors; ++i) {
slouken@1895
   596
                SDL_RWwrite(dst, &colors[i].b, 1, 1);
slouken@1895
   597
                SDL_RWwrite(dst, &colors[i].g, 1, 1);
slouken@1895
   598
                SDL_RWwrite(dst, &colors[i].r, 1, 1);
slouken@7024
   599
                SDL_RWwrite(dst, &colors[i].a, 1, 1);
slouken@1895
   600
            }
slouken@1895
   601
        }
slouken@0
   602
slouken@1895
   603
        /* Write the bitmap offset */
slouken@6666
   604
        bfOffBits = (Uint32)(SDL_RWtell(dst) - fp_offset);
slouken@1895
   605
        if (SDL_RWseek(dst, fp_offset + 10, RW_SEEK_SET) < 0) {
slouken@1895
   606
            SDL_Error(SDL_EFSEEK);
slouken@1895
   607
        }
slouken@1895
   608
        SDL_WriteLE32(dst, bfOffBits);
slouken@1895
   609
        if (SDL_RWseek(dst, fp_offset + bfOffBits, RW_SEEK_SET) < 0) {
slouken@1895
   610
            SDL_Error(SDL_EFSEEK);
slouken@1895
   611
        }
slouken@0
   612
slouken@1895
   613
        /* Write the bitmap image upside down */
slouken@1895
   614
        bits = (Uint8 *) surface->pixels + (surface->h * surface->pitch);
slouken@1895
   615
        pad = ((bw % 4) ? (4 - (bw % 4)) : 0);
slouken@1895
   616
        while (bits > (Uint8 *) surface->pixels) {
slouken@1895
   617
            bits -= surface->pitch;
slouken@1895
   618
            if (SDL_RWwrite(dst, bits, 1, bw) != bw) {
slouken@1895
   619
                SDL_Error(SDL_EFWRITE);
slouken@1895
   620
                break;
slouken@1895
   621
            }
slouken@1895
   622
            if (pad) {
slouken@1895
   623
                const Uint8 padbyte = 0;
slouken@1895
   624
                for (i = 0; i < pad; ++i) {
slouken@1895
   625
                    SDL_RWwrite(dst, &padbyte, 1, 1);
slouken@1895
   626
                }
slouken@1895
   627
            }
slouken@1895
   628
        }
slouken@0
   629
slouken@1895
   630
        /* Write the BMP file size */
slouken@6666
   631
        bfSize = (Uint32)(SDL_RWtell(dst) - fp_offset);
slouken@1895
   632
        if (SDL_RWseek(dst, fp_offset + 2, RW_SEEK_SET) < 0) {
slouken@1895
   633
            SDL_Error(SDL_EFSEEK);
slouken@1895
   634
        }
slouken@1895
   635
        SDL_WriteLE32(dst, bfSize);
slouken@1895
   636
        if (SDL_RWseek(dst, fp_offset + bfSize, RW_SEEK_SET) < 0) {
slouken@1895
   637
            SDL_Error(SDL_EFSEEK);
slouken@1895
   638
        }
slouken@0
   639
slouken@1895
   640
        /* Close it up.. */
slouken@1895
   641
        SDL_UnlockSurface(surface);
slouken@1895
   642
        if (surface != saveme) {
slouken@1895
   643
            SDL_FreeSurface(surface);
slouken@1895
   644
        }
slouken@1895
   645
    }
slouken@0
   646
slouken@1895
   647
    if (freedst && dst) {
slouken@1895
   648
        SDL_RWclose(dst);
slouken@1895
   649
    }
slouken@1895
   650
    return ((SDL_strcmp(SDL_GetError(), "") == 0) ? 0 : -1);
slouken@0
   651
}
slouken@1895
   652
slouken@1895
   653
/* vi: set ts=4 sw=4 expandtab: */