Function LoadOS21XBMP

Dependencies/FreeImage/Source/FreeImage/PluginBMP.cpp:876–1014

// --------------------------------------------------------------------------

static FIBITMAP *
LoadOS21XBMP(FreeImageIO *io, fi_handle handle, int flags, unsigned bitmap_bits_offset) {
	FIBITMAP *dib = NULL;

	try {
		BOOL header_only = (flags & FIF_LOAD_NOPIXELS) == FIF_LOAD_NOPIXELS;

		BITMAPINFOOS2_1X_HEADER bios2_1x;

		io->read_proc(&bios2_1x, sizeof(BITMAPINFOOS2_1X_HEADER), 1, handle);
#ifdef FREEIMAGE_BIGENDIAN
		SwapOS21XHeader(&bios2_1x);
#endif
		// keep some general information about the bitmap

		unsigned used_colors = 0;
		unsigned width		= bios2_1x.biWidth;
		unsigned height		= bios2_1x.biHeight;	// WARNING: height can be < 0 => check each read_proc using 'height' as a parameter
		unsigned bit_count	= bios2_1x.biBitCount;
		unsigned pitch		= CalculatePitch(CalculateLine(width, bit_count));
		
		switch (bit_count) {
			case 1 :
			case 4 :
			case 8 :
			{
				used_colors = CalculateUsedPaletteEntries(bit_count);
				
				// allocate enough memory to hold the bitmap (header, palette, pixels) and read the palette

				dib = FreeImage_AllocateHeader(header_only, width, height, bit_count);

				if (dib == NULL) {
					throw FI_MSG_ERROR_DIB_MEMORY;
				}

				// set resolution information to default values (72 dpi in english units)
				FreeImage_SetDotsPerMeterX(dib, 2835);
				FreeImage_SetDotsPerMeterY(dib, 2835);
				
				// load the palette

				RGBQUAD *pal = FreeImage_GetPalette(dib);

				for (unsigned count = 0; count < used_colors; count++) {
					FILE_BGR bgr;

					io->read_proc(&bgr, sizeof(FILE_BGR), 1, handle);
					
					pal[count].rgbRed	= bgr.r;
					pal[count].rgbGreen = bgr.g;
					pal[count].rgbBlue	= bgr.b;
				}
				
				if(header_only) {
					// header only mode
					return dib;
				}