| /* |
| Simple DirectMedia Layer |
| Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org> |
| |
| This software is provided 'as-is', without any express or implied |
| warranty. In no event will the authors be held liable for any damages |
| arising from the use of this software. |
| |
| Permission is granted to anyone to use this software for any purpose, |
| including commercial applications, and to alter it and redistribute it |
| freely, subject to the following restrictions: |
| |
| 1. The origin of this software must not be misrepresented; you must not |
| claim that you wrote the original software. If you use this software |
| in a product, an acknowledgment in the product documentation would be |
| appreciated but is not required. |
| 2. Altered source versions must be plainly marked as such, and must not be |
| misrepresented as being the original software. |
| 3. This notice may not be removed or altered from any source distribution. |
| */ |
| #include "SDL_internal.h" |
| |
| /* |
| Code to load and save surfaces in Windows BMP format. |
| |
| Why support BMP format? Well, it's a native format for Windows, and |
| most image processing programs can read and write it. It would be nice |
| to be able to have at least one image format that we can natively load |
| and save, and since PNG is so complex that it would bloat the library, |
| BMP is a good alternative. |
| |
| This code currently supports Win32 DIBs in uncompressed 8 and 24 bpp. |
| */ |
| |
| #include "SDL_pixels_c.h" |
| #include "SDL_surface_c.h" |
| |
| #define SAVE_32BIT_BMP |
| |
| // Compression encodings for BMP files |
| #ifndef BI_RGB |
| #define BI_RGB 0 |
| #define BI_RLE8 1 |
| #define BI_RLE4 2 |
| #define BI_BITFIELDS 3 |
| #endif |
| |
| // Logical color space values for BMP files |
| // https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-wmf/eb4bbd50-b3ce-4917-895c-be31f214797f |
| #ifndef LCS_WINDOWS_COLOR_SPACE |
| // 0x57696E20 == "Win " |
| #define LCS_WINDOWS_COLOR_SPACE 0x57696E20 |
| #endif |
| |
| #ifndef LCS_sRGB |
| // 0x73524742 == "sRGB" |
| #define LCS_sRGB 0x73524742 |
| #endif |
| |
| // Logical/physical color relationship |
| // https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-wmf/9fec0834-607d-427d-abd5-ab240fb0db38 |
| #ifndef LCS_GM_GRAPHICS |
| #define LCS_GM_GRAPHICS 0x00000002 |
| #endif |
| |
| static bool readRlePixels(SDL_Surface *surface, SDL_IOStream *src, int isRle8) |
| { |
| /* |
| | Sets the surface pixels from src. A bmp image is upside down. |
| */ |
| int pitch = surface->pitch; |
| int height = surface->h; |
| Uint8 *start = (Uint8 *)surface->pixels; |
| Uint8 *end = start + (height * pitch); |
| Uint8 *bits = end - pitch, *spot; |
| int ofs = 0; |
| Uint8 ch; |
| Uint8 needsPad; |
| const int pixels_per_byte = (isRle8 ? 1 : 2); |
| |
| #define COPY_PIXEL(x) \ |
| spot = &bits[ofs++]; \ |
| if (spot >= start && spot < end) \ |
| *spot = (x) |
| |
| for (;;) { |
| if (!SDL_ReadU8(src, &ch)) { |
| return false; |
| } |
| /* |
| | encoded mode starts with a run length, and then a byte |
| | with two colour indexes to alternate between for the run |
| */ |
| if (ch) { |
| Uint8 pixelvalue; |
| if (!SDL_ReadU8(src, &pixelvalue)) { |
| return false; |
| } |
| ch /= pixels_per_byte; |
| do { |
| COPY_PIXEL(pixelvalue); |
| } while (--ch); |
| } else { |
| /* |
| | A leading zero is an escape; it may signal the end of the bitmap, |
| | a cursor move, or some absolute data. |
| | zero tag may be absolute mode or an escape |
| */ |
| if (!SDL_ReadU8(src, &ch)) { |
| return false; |
| } |
| switch (ch) { |
| case 0: // end of line |
| ofs = 0; |
| bits -= pitch; // go to previous |
| break; |
| case 1: // end of bitmap |
| return true; // success! |
| case 2: // delta |
| if (!SDL_ReadU8(src, &ch)) { |
| return false; |
| } |
| ofs += ch / pixels_per_byte; |
| |
| if (!SDL_ReadU8(src, &ch)) { |
| return false; |
| } |
| bits -= ((ch / pixels_per_byte) * pitch); |
| break; |
| default: // no compression |
| ch /= pixels_per_byte; |
| needsPad = (ch & 1); |
| do { |
| Uint8 pixelvalue; |
| if (!SDL_ReadU8(src, &pixelvalue)) { |
| return false; |
| } |
| COPY_PIXEL(pixelvalue); |
| } while (--ch); |
| |
| // pad at even boundary |
| if (needsPad && !SDL_ReadU8(src, &ch)) { |
| return false; |
| } |
| break; |
| } |
| } |
| } |
| } |
| |
| static void CorrectAlphaChannel(SDL_Surface *surface) |
| { |
| // Check to see if there is any alpha channel data |
| bool hasAlpha = false; |
| #if SDL_BYTEORDER == SDL_BIG_ENDIAN |
| int alphaChannelOffset = 0; |
| #else |
| int alphaChannelOffset = 3; |
| #endif |
| Uint8 *alpha = ((Uint8 *)surface->pixels) + alphaChannelOffset; |
| Uint8 *end = alpha + surface->h * surface->pitch; |
| |
| while (alpha < end) { |
| if (*alpha != 0) { |
| hasAlpha = true; |
| break; |
| } |
| alpha += 4; |
| } |
| |
| if (!hasAlpha) { |
| alpha = ((Uint8 *)surface->pixels) + alphaChannelOffset; |
| while (alpha < end) { |
| *alpha = SDL_ALPHA_OPAQUE; |
| alpha += 4; |
| } |
| } |
| } |
| |
| SDL_Surface *SDL_LoadBMP_IO(SDL_IOStream *src, bool closeio) |
| { |
| bool was_error = true; |
| Sint64 fp_offset = 0; |
| int i, pad; |
| SDL_Surface *surface; |
| Uint32 Rmask = 0; |
| Uint32 Gmask = 0; |
| Uint32 Bmask = 0; |
| Uint32 Amask = 0; |
| Uint8 *bits; |
| Uint8 *top, *end; |
| bool topDown; |
| bool haveRGBMasks = false; |
| bool haveAlphaMask = false; |
| bool correctAlpha = false; |
| |
| // The Win32 BMP file header (14 bytes) |
| char magic[2]; |
| // Uint32 bfSize; |
| // Uint16 bfReserved1; |
| // Uint16 bfReserved2; |
| Uint32 bfOffBits; |
| |
| // The Win32 BITMAPINFOHEADER struct (40 bytes) |
| Uint32 biSize; |
| Sint32 biWidth = 0; |
| Sint32 biHeight = 0; |
| // Uint16 biPlanes; |
| Uint16 biBitCount = 0; |
| Uint32 biCompression = 0; |
| // Uint32 biSizeImage; |
| // Sint32 biXPelsPerMeter; |
| // Sint32 biYPelsPerMeter; |
| Uint32 biClrUsed = 0; |
| // Uint32 biClrImportant; |
| |
| // Make sure we are passed a valid data source |
| surface = NULL; |
| if (!src) { |
| SDL_InvalidParamError("src"); |
| goto done; |
| } |
| |
| // Read in the BMP file header |
| fp_offset = SDL_TellIO(src); |
| if (fp_offset < 0) { |
| goto done; |
| } |
| SDL_ClearError(); |
| if (SDL_ReadIO(src, magic, 2) != 2) { |
| goto done; |
| } |
| if (SDL_strncmp(magic, "BM", 2) != 0) { |
| SDL_SetError("File is not a Windows BMP file"); |
| goto done; |
| } |
| if (!SDL_ReadU32LE(src, NULL /* bfSize */) || |
| !SDL_ReadU16LE(src, NULL /* bfReserved1 */) || |
| !SDL_ReadU16LE(src, NULL /* bfReserved2 */) || |
| !SDL_ReadU32LE(src, &bfOffBits)) { |
| goto done; |
| } |
| |
| // Read the Win32 BITMAPINFOHEADER |
| if (!SDL_ReadU32LE(src, &biSize)) { |
| goto done; |
| } |
| if (biSize == 12) { // really old BITMAPCOREHEADER |
| Uint16 biWidth16, biHeight16; |
| if (!SDL_ReadU16LE(src, &biWidth16) || |
| !SDL_ReadU16LE(src, &biHeight16) || |
| !SDL_ReadU16LE(src, NULL /* biPlanes */) || |
| !SDL_ReadU16LE(src, &biBitCount)) { |
| goto done; |
| } |
| biWidth = biWidth16; |
| biHeight = biHeight16; |
| biCompression = BI_RGB; |
| // biSizeImage = 0; |
| // biXPelsPerMeter = 0; |
| // biYPelsPerMeter = 0; |
| biClrUsed = 0; |
| // biClrImportant = 0; |
| } else if (biSize >= 40) { // some version of BITMAPINFOHEADER |
| Uint32 headerSize; |
| if (!SDL_ReadS32LE(src, &biWidth) || |
| !SDL_ReadS32LE(src, &biHeight) || |
| !SDL_ReadU16LE(src, NULL /* biPlanes */) || |
| !SDL_ReadU16LE(src, &biBitCount) || |
| !SDL_ReadU32LE(src, &biCompression) || |
| !SDL_ReadU32LE(src, NULL /* biSizeImage */) || |
| !SDL_ReadU32LE(src, NULL /* biXPelsPerMeter */) || |
| !SDL_ReadU32LE(src, NULL /* biYPelsPerMeter */) || |
| !SDL_ReadU32LE(src, &biClrUsed) || |
| !SDL_ReadU32LE(src, NULL /* biClrImportant */)) { |
| goto done; |
| } |
| |
| // 64 == BITMAPCOREHEADER2, an incompatible OS/2 2.x extension. Skip this stuff for now. |
| if (biSize != 64) { |
| /* This is complicated. If compression is BI_BITFIELDS, then |
| we have 3 DWORDS that specify the RGB masks. This is either |
| stored here in an BITMAPV2INFOHEADER (which only differs in |
| that it adds these RGB masks) and biSize >= 52, or we've got |
| these masks stored in the exact same place, but strictly |
| speaking, this is the bmiColors field in BITMAPINFO immediately |
| following the legacy v1 info header, just past biSize. */ |
| if (biCompression == BI_BITFIELDS) { |
| haveRGBMasks = true; |
| if (!SDL_ReadU32LE(src, &Rmask) || |
| !SDL_ReadU32LE(src, &Gmask) || |
| !SDL_ReadU32LE(src, &Bmask)) { |
| goto done; |
| } |
| |
| // ...v3 adds an alpha mask. |
| if (biSize >= 56) { // BITMAPV3INFOHEADER; adds alpha mask |
| haveAlphaMask = true; |
| if (!SDL_ReadU32LE(src, &Amask)) { |
| goto done; |
| } |
| } |
| } else { |
| // the mask fields are ignored for v2+ headers if not BI_BITFIELD. |
| if (biSize >= 52) { // BITMAPV2INFOHEADER; adds RGB masks |
| if (!SDL_ReadU32LE(src, NULL /* Rmask */) || |
| !SDL_ReadU32LE(src, NULL /* Gmask */) || |
| !SDL_ReadU32LE(src, NULL /* Bmask */)) { |
| goto done; |
| } |
| } |
| if (biSize >= 56) { // BITMAPV3INFOHEADER; adds alpha mask |
| if (!SDL_ReadU32LE(src, NULL /* Amask */)) { |
| goto done; |
| } |
| } |
| } |
| |
| /* Insert other fields here; Wikipedia and MSDN say we're up to |
| v5 of this header, but we ignore those for now (they add gamma, |
| color spaces, etc). Ignoring the weird OS/2 2.x format, we |
| currently parse up to v3 correctly (hopefully!). */ |
| } |
| |
| // skip any header bytes we didn't handle... |
| headerSize = (Uint32)(SDL_TellIO(src) - (fp_offset + 14)); |
| if (biSize > headerSize) { |
| if (SDL_SeekIO(src, (biSize - headerSize), SDL_IO_SEEK_CUR) < 0) { |
| goto done; |
| } |
| } |
| } |
| if (biWidth <= 0 || biHeight == 0) { |
| SDL_SetError("BMP file with bad dimensions (%" SDL_PRIs32 "x%" SDL_PRIs32 ")", biWidth, biHeight); |
| goto done; |
| } |
| if (biHeight < 0) { |
| topDown = true; |
| biHeight = -biHeight; |
| } else { |
| topDown = false; |
| } |
| |
| // Check for read error |
| if (SDL_strcmp(SDL_GetError(), "") != 0) { |
| goto done; |
| } |
| |
| // Reject invalid bit depths |
| switch (biBitCount) { |
| case 0: |
| case 3: |
| case 5: |
| case 6: |
| case 7: |
| SDL_SetError("%u bpp BMP images are not supported", biBitCount); |
| goto done; |
| default: |
| break; |
| } |
| |
| // RLE4 and RLE8 BMP compression is supported |
| switch (biCompression) { |
| case BI_RGB: |
| // If there are no masks, use the defaults |
| SDL_assert(!haveRGBMasks); |
| SDL_assert(!haveAlphaMask); |
| // Default values for the BMP format |
| switch (biBitCount) { |
| case 15: |
| case 16: |
| // SDL_PIXELFORMAT_XRGB1555 or SDL_PIXELFORMAT_ARGB1555 if Amask |
| Rmask = 0x7C00; |
| Gmask = 0x03E0; |
| Bmask = 0x001F; |
| break; |
| case 24: |
| #if SDL_BYTEORDER == SDL_BIG_ENDIAN |
| // SDL_PIXELFORMAT_RGB24 |
| Rmask = 0x000000FF; |
| Gmask = 0x0000FF00; |
| Bmask = 0x00FF0000; |
| #else |
| // SDL_PIXELFORMAT_BGR24 |
| Rmask = 0x00FF0000; |
| Gmask = 0x0000FF00; |
| Bmask = 0x000000FF; |
| #endif |
| break; |
| case 32: |
| // We don't know if this has alpha channel or not |
| correctAlpha = true; |
| // SDL_PIXELFORMAT_RGBA8888 |
| Amask = 0xFF000000; |
| Rmask = 0x00FF0000; |
| Gmask = 0x0000FF00; |
| Bmask = 0x000000FF; |
| break; |
| default: |
| break; |
| } |
| break; |
| |
| case BI_BITFIELDS: |
| break; // we handled this in the info header. |
| |
| default: |
| break; |
| } |
| |
| // Create a compatible surface, note that the colors are RGB ordered |
| { |
| SDL_PixelFormat format; |
| |
| // Get the pixel format |
| format = SDL_GetPixelFormatForMasks(biBitCount, Rmask, Gmask, Bmask, Amask); |
| surface = SDL_CreateSurface(biWidth, biHeight, format); |
| |
| if (!surface) { |
| goto done; |
| } |
| } |
| |
| // Load the palette, if any |
| if (SDL_ISPIXELFORMAT_INDEXED(surface->format)) { |
| SDL_Palette *palette = SDL_CreateSurfacePalette(surface); |
| if (!palette) { |
| goto done; |
| } |
| |
| if (SDL_SeekIO(src, fp_offset + 14 + biSize, SDL_IO_SEEK_SET) < 0) { |
| SDL_SetError("Error seeking in datastream"); |
| goto done; |
| } |
| |
| if (biBitCount >= 32) { // we shift biClrUsed by this value later. |
| SDL_SetError("Unsupported or incorrect biBitCount field"); |
| goto done; |
| } |
| |
| if (biClrUsed == 0) { |
| biClrUsed = 1 << biBitCount; |
| } |
| |
| if (biClrUsed > (Uint32)palette->ncolors) { |
| biClrUsed = 1 << biBitCount; // try forcing it? |
| if (biClrUsed > (Uint32)palette->ncolors) { |
| SDL_SetError("Unsupported or incorrect biClrUsed field"); |
| goto done; |
| } |
| } |
| palette->ncolors = biClrUsed; |
| |
| if (biSize == 12) { |
| for (i = 0; i < palette->ncolors; ++i) { |
| if (!SDL_ReadU8(src, &palette->colors[i].b) || |
| !SDL_ReadU8(src, &palette->colors[i].g) || |
| !SDL_ReadU8(src, &palette->colors[i].r)) { |
| goto done; |
| } |
| palette->colors[i].a = SDL_ALPHA_OPAQUE; |
| } |
| } else { |
| for (i = 0; i < palette->ncolors; ++i) { |
| if (!SDL_ReadU8(src, &palette->colors[i].b) || |
| !SDL_ReadU8(src, &palette->colors[i].g) || |
| !SDL_ReadU8(src, &palette->colors[i].r) || |
| !SDL_ReadU8(src, &palette->colors[i].a)) { |
| goto done; |
| } |
| |
| /* According to Microsoft documentation, the fourth element |
| is reserved and must be zero, so we shouldn't treat it as |
| alpha. |
| */ |
| palette->colors[i].a = SDL_ALPHA_OPAQUE; |
| } |
| } |
| } |
| |
| // Read the surface pixels. Note that the bmp image is upside down |
| if (SDL_SeekIO(src, fp_offset + bfOffBits, SDL_IO_SEEK_SET) < 0) { |
| SDL_SetError("Error seeking in datastream"); |
| goto done; |
| } |
| if ((biCompression == BI_RLE4) || (biCompression == BI_RLE8)) { |
| if (!readRlePixels(surface, src, biCompression == BI_RLE8)) { |
| SDL_SetError("Error reading from datastream"); |
| goto done; |
| } |
| |
| // Success! |
| was_error = false; |
| goto done; |
| } |
| top = (Uint8 *)surface->pixels; |
| end = (Uint8 *)surface->pixels + (surface->h * surface->pitch); |
| pad = ((surface->pitch % 4) ? (4 - (surface->pitch % 4)) : 0); |
| if (topDown) { |
| bits = top; |
| } else { |
| bits = end - surface->pitch; |
| } |
| while (bits >= top && bits < end) { |
| if (SDL_ReadIO(src, bits, surface->pitch) != (size_t)surface->pitch) { |
| goto done; |
| } |
| if (biBitCount == 8 && surface->palette && biClrUsed < (1u << biBitCount)) { |
| for (i = 0; i < surface->w; ++i) { |
| if (bits[i] >= biClrUsed) { |
| SDL_SetError("A BMP image contains a pixel with a color out of the palette"); |
| goto done; |
| } |
| } |
| } |
| #if SDL_BYTEORDER == SDL_BIG_ENDIAN |
| /* Byte-swap the pixels if needed. Note that the 24bpp |
| case has already been taken care of above. */ |
| switch (biBitCount) { |
| case 15: |
| case 16: |
| { |
| Uint16 *pix = (Uint16 *)bits; |
| for (i = 0; i < surface->w; i++) { |
| pix[i] = SDL_Swap16(pix[i]); |
| } |
| break; |
| } |
| |
| case 32: |
| { |
| Uint32 *pix = (Uint32 *)bits; |
| for (i = 0; i < surface->w; i++) { |
| pix[i] = SDL_Swap32(pix[i]); |
| } |
| break; |
| } |
| } |
| #endif |
| |
| // Skip padding bytes, ugh |
| if (pad) { |
| Uint8 padbyte; |
| for (i = 0; i < pad; ++i) { |
| if (!SDL_ReadU8(src, &padbyte)) { |
| goto done; |
| } |
| } |
| } |
| if (topDown) { |
| bits += surface->pitch; |
| } else { |
| bits -= surface->pitch; |
| } |
| } |
| if (correctAlpha) { |
| CorrectAlphaChannel(surface); |
| } |
| |
| was_error = false; |
| |
| done: |
| if (was_error) { |
| if (src) { |
| SDL_SeekIO(src, fp_offset, SDL_IO_SEEK_SET); |
| } |
| SDL_DestroySurface(surface); |
| surface = NULL; |
| } |
| if (closeio && src) { |
| SDL_CloseIO(src); |
| } |
| return surface; |
| } |
| |
| SDL_Surface *SDL_LoadBMP(const char *file) |
| { |
| SDL_IOStream *stream = SDL_IOFromFile(file, "rb"); |
| if (!stream) { |
| return NULL; |
| } |
| return SDL_LoadBMP_IO(stream, true); |
| } |
| |
| bool SDL_SaveBMP_IO(SDL_Surface *surface, SDL_IOStream *dst, bool closeio) |
| { |
| bool was_error = true; |
| Sint64 fp_offset, new_offset; |
| int i, pad; |
| SDL_Surface *intermediate_surface = NULL; |
| Uint8 *bits; |
| bool save32bit = false; |
| bool saveLegacyBMP = false; |
| |
| // The Win32 BMP file header (14 bytes) |
| char magic[2] = { 'B', 'M' }; |
| Uint32 bfSize; |
| Uint16 bfReserved1; |
| Uint16 bfReserved2; |
| Uint32 bfOffBits; |
| |
| // The Win32 BITMAPINFOHEADER struct (40 bytes) |
| Uint32 biSize; |
| Sint32 biWidth; |
| Sint32 biHeight; |
| Uint16 biPlanes; |
| Uint16 biBitCount; |
| Uint32 biCompression; |
| Uint32 biSizeImage; |
| Sint32 biXPelsPerMeter; |
| Sint32 biYPelsPerMeter; |
| Uint32 biClrUsed; |
| Uint32 biClrImportant; |
| |
| // The additional header members from the Win32 BITMAPV4HEADER struct (108 bytes in total) |
| Uint32 bV4RedMask = 0; |
| Uint32 bV4GreenMask = 0; |
| Uint32 bV4BlueMask = 0; |
| Uint32 bV4AlphaMask = 0; |
| Uint32 bV4CSType = 0; |
| Sint32 bV4Endpoints[3 * 3] = { 0 }; |
| Uint32 bV4GammaRed = 0; |
| Uint32 bV4GammaGreen = 0; |
| Uint32 bV4GammaBlue = 0; |
| |
| // The additional header members from the Win32 BITMAPV5HEADER struct (124 bytes in total) |
| Uint32 bV5Intent = 0; |
| Uint32 bV5ProfileData = 0; |
| Uint32 bV5ProfileSize = 0; |
| Uint32 bV5Reserved = 0; |
| |
| // Make sure we have somewhere to save |
| if (!SDL_SurfaceValid(surface)) { |
| SDL_InvalidParamError("surface"); |
| goto done; |
| } |
| if (!dst) { |
| SDL_InvalidParamError("dst"); |
| goto done; |
| } |
| |
| #ifdef SAVE_32BIT_BMP |
| // We can save alpha information in a 32-bit BMP |
| if (SDL_BITSPERPIXEL(surface->format) >= 8 && |
| (SDL_ISPIXELFORMAT_ALPHA(surface->format) || |
| surface->map.info.flags & SDL_COPY_COLORKEY)) { |
| save32bit = true; |
| } |
| #endif // SAVE_32BIT_BMP |
| |
| if (surface->palette && !save32bit) { |
| if (SDL_BITSPERPIXEL(surface->format) == 8) { |
| intermediate_surface = surface; |
| } else { |
| SDL_SetError("%u bpp BMP files not supported", |
| SDL_BITSPERPIXEL(surface->format)); |
| goto done; |
| } |
| } else if ((surface->format == SDL_PIXELFORMAT_BGR24 && !save32bit) || |
| (surface->format == SDL_PIXELFORMAT_BGRA32 && save32bit)) { |
| intermediate_surface = surface; |
| } else { |
| SDL_PixelFormat pixel_format; |
| |
| /* If the surface has a colorkey or alpha channel we'll save a |
| 32-bit BMP with alpha channel, otherwise save a 24-bit BMP. */ |
| if (save32bit) { |
| pixel_format = SDL_PIXELFORMAT_BGRA32; |
| } else { |
| pixel_format = SDL_PIXELFORMAT_BGR24; |
| } |
| intermediate_surface = SDL_ConvertSurface(surface, pixel_format); |
| if (!intermediate_surface) { |
| SDL_SetError("Couldn't convert image to %d bpp", |
| (int)SDL_BITSPERPIXEL(pixel_format)); |
| goto done; |
| } |
| } |
| |
| if (save32bit) { |
| saveLegacyBMP = SDL_GetHintBoolean(SDL_HINT_BMP_SAVE_LEGACY_FORMAT, false); |
| } |
| |
| if (SDL_LockSurface(intermediate_surface)) { |
| const size_t bw = intermediate_surface->w * intermediate_surface->fmt->bytes_per_pixel; |
| |
| // Set the BMP file header values |
| bfSize = 0; // We'll write this when we're done |
| bfReserved1 = 0; |
| bfReserved2 = 0; |
| bfOffBits = 0; // We'll write this when we're done |
| |
| // Write the BMP file header values |
| fp_offset = SDL_TellIO(dst); |
| if (fp_offset < 0) { |
| goto done; |
| } |
| if (SDL_WriteIO(dst, magic, 2) != 2 || |
| !SDL_WriteU32LE(dst, bfSize) || |
| !SDL_WriteU16LE(dst, bfReserved1) || |
| !SDL_WriteU16LE(dst, bfReserved2) || |
| !SDL_WriteU32LE(dst, bfOffBits)) { |
| goto done; |
| } |
| |
| // Set the BMP info values |
| biSize = 40; |
| biWidth = intermediate_surface->w; |
| biHeight = intermediate_surface->h; |
| biPlanes = 1; |
| biBitCount = intermediate_surface->fmt->bits_per_pixel; |
| biCompression = BI_RGB; |
| biSizeImage = intermediate_surface->h * intermediate_surface->pitch; |
| biXPelsPerMeter = 0; |
| biYPelsPerMeter = 0; |
| if (intermediate_surface->palette) { |
| biClrUsed = intermediate_surface->palette->ncolors; |
| } else { |
| biClrUsed = 0; |
| } |
| biClrImportant = 0; |
| |
| // Set the BMP info values |
| if (save32bit && !saveLegacyBMP) { |
| biSize = 124; |
| // Version 4 values |
| biCompression = BI_BITFIELDS; |
| // The BMP format is always little endian, these masks stay the same |
| bV4RedMask = 0x00ff0000; |
| bV4GreenMask = 0x0000ff00; |
| bV4BlueMask = 0x000000ff; |
| bV4AlphaMask = 0xff000000; |
| bV4CSType = LCS_sRGB; |
| bV4GammaRed = 0; |
| bV4GammaGreen = 0; |
| bV4GammaBlue = 0; |
| // Version 5 values |
| bV5Intent = LCS_GM_GRAPHICS; |
| bV5ProfileData = 0; |
| bV5ProfileSize = 0; |
| bV5Reserved = 0; |
| } |
| |
| // Write the BMP info values |
| if (!SDL_WriteU32LE(dst, biSize) || |
| !SDL_WriteS32LE(dst, biWidth) || |
| !SDL_WriteS32LE(dst, biHeight) || |
| !SDL_WriteU16LE(dst, biPlanes) || |
| !SDL_WriteU16LE(dst, biBitCount) || |
| !SDL_WriteU32LE(dst, biCompression) || |
| !SDL_WriteU32LE(dst, biSizeImage) || |
| !SDL_WriteU32LE(dst, biXPelsPerMeter) || |
| !SDL_WriteU32LE(dst, biYPelsPerMeter) || |
| !SDL_WriteU32LE(dst, biClrUsed) || |
| !SDL_WriteU32LE(dst, biClrImportant)) { |
| goto done; |
| } |
| |
| // Write the BMP info values |
| if (save32bit && !saveLegacyBMP) { |
| // Version 4 values |
| if (!SDL_WriteU32LE(dst, bV4RedMask) || |
| !SDL_WriteU32LE(dst, bV4GreenMask) || |
| !SDL_WriteU32LE(dst, bV4BlueMask) || |
| !SDL_WriteU32LE(dst, bV4AlphaMask) || |
| !SDL_WriteU32LE(dst, bV4CSType)) { |
| goto done; |
| } |
| for (i = 0; i < 3 * 3; i++) { |
| if (!SDL_WriteU32LE(dst, bV4Endpoints[i])) { |
| goto done; |
| } |
| } |
| if (!SDL_WriteU32LE(dst, bV4GammaRed) || |
| !SDL_WriteU32LE(dst, bV4GammaGreen) || |
| !SDL_WriteU32LE(dst, bV4GammaBlue)) { |
| goto done; |
| } |
| // Version 5 values |
| if (!SDL_WriteU32LE(dst, bV5Intent) || |
| !SDL_WriteU32LE(dst, bV5ProfileData) || |
| !SDL_WriteU32LE(dst, bV5ProfileSize) || |
| !SDL_WriteU32LE(dst, bV5Reserved)) { |
| goto done; |
| } |
| } |
| |
| // Write the palette (in BGR color order) |
| if (intermediate_surface->palette) { |
| SDL_Color *colors; |
| int ncolors; |
| |
| colors = intermediate_surface->palette->colors; |
| ncolors = intermediate_surface->palette->ncolors; |
| for (i = 0; i < ncolors; ++i) { |
| if (!SDL_WriteU8(dst, colors[i].b) || |
| !SDL_WriteU8(dst, colors[i].g) || |
| !SDL_WriteU8(dst, colors[i].r) || |
| !SDL_WriteU8(dst, colors[i].a)) { |
| goto done; |
| } |
| } |
| } |
| |
| // Write the bitmap offset |
| bfOffBits = (Uint32)(SDL_TellIO(dst) - fp_offset); |
| if (SDL_SeekIO(dst, fp_offset + 10, SDL_IO_SEEK_SET) < 0) { |
| goto done; |
| } |
| if (!SDL_WriteU32LE(dst, bfOffBits)) { |
| goto done; |
| } |
| if (SDL_SeekIO(dst, fp_offset + bfOffBits, SDL_IO_SEEK_SET) < 0) { |
| goto done; |
| } |
| |
| // Write the bitmap image upside down |
| bits = (Uint8 *)intermediate_surface->pixels + (intermediate_surface->h * intermediate_surface->pitch); |
| pad = ((bw % 4) ? (4 - (bw % 4)) : 0); |
| while (bits > (Uint8 *)intermediate_surface->pixels) { |
| bits -= intermediate_surface->pitch; |
| if (SDL_WriteIO(dst, bits, bw) != bw) { |
| goto done; |
| } |
| if (pad) { |
| const Uint8 padbyte = 0; |
| for (i = 0; i < pad; ++i) { |
| if (!SDL_WriteU8(dst, padbyte)) { |
| goto done; |
| } |
| } |
| } |
| } |
| |
| // Write the BMP file size |
| new_offset = SDL_TellIO(dst); |
| if (new_offset < 0) { |
| goto done; |
| } |
| bfSize = (Uint32)(new_offset - fp_offset); |
| if (SDL_SeekIO(dst, fp_offset + 2, SDL_IO_SEEK_SET) < 0) { |
| goto done; |
| } |
| if (!SDL_WriteU32LE(dst, bfSize)) { |
| goto done; |
| } |
| if (SDL_SeekIO(dst, fp_offset + bfSize, SDL_IO_SEEK_SET) < 0) { |
| goto done; |
| } |
| |
| // Close it up.. |
| SDL_UnlockSurface(intermediate_surface); |
| |
| was_error = false; |
| } |
| |
| done: |
| if (intermediate_surface && intermediate_surface != surface) { |
| SDL_DestroySurface(intermediate_surface); |
| } |
| if (closeio && dst) { |
| if (!SDL_CloseIO(dst)) { |
| was_error = true; |
| } |
| } |
| if (was_error) { |
| return false; |
| } |
| return true; |
| } |
| |
| bool SDL_SaveBMP(SDL_Surface *surface, const char *file) |
| { |
| SDL_IOStream *stream = SDL_IOFromFile(file, "wb"); |
| if (!stream) { |
| return false; |
| } |
| return SDL_SaveBMP_IO(surface, stream, true); |
| } |
