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src/Source/FreeImage/PluginWebP.cpp  view on Meta::CPAN

	const uint8_t* data = webp_image->bytes;	// raw image data
	const size_t data_size = webp_image->size;	// raw image size

    VP8StatusCode webp_status = VP8_STATUS_OK;

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

	// Main object storing the configuration for advanced decoding
	WebPDecoderConfig decoder_config;
	// Output buffer
	WebPDecBuffer* const output_buffer = &decoder_config.output;
	// Features gathered from the bitstream
	WebPBitstreamFeatures* const bitstream = &decoder_config.input;

	try {
		// Initialize the configuration as empty
		// This function must always be called first, unless WebPGetFeatures() is to be called
		if(!WebPInitDecoderConfig(&decoder_config)) {
			throw "Library version mismatch";
		}

		// Retrieve features from the bitstream
		// The bitstream structure is filled with information gathered from the bitstream
		webp_status = WebPGetFeatures(data, data_size, bitstream);
		if(webp_status != VP8_STATUS_OK) {
			throw FI_MSG_ERROR_PARSING;
		}

		// Allocate output dib

		unsigned bpp = bitstream->has_alpha ? 32 : 24;	
		unsigned width = (unsigned)bitstream->width;
		unsigned height = (unsigned)bitstream->height;

		dib = FreeImage_AllocateHeader(header_only, width, height, bpp, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK);
		if(!dib) {
			throw FI_MSG_ERROR_DIB_MEMORY;
		}

		if(header_only) {
			WebPFreeDecBuffer(output_buffer);
			return dib;
		}

		// --- Set decoding options ---

		// use multi-threaded decoding
		decoder_config.options.use_threads = 1;
		// set output color space
		output_buffer->colorspace = bitstream->has_alpha ? MODE_BGRA : MODE_BGR;

		// ---

		// decode the input stream, taking 'config' into account. 
		
		webp_status = WebPDecode(data, data_size, &decoder_config);
		if(webp_status != VP8_STATUS_OK) {
			throw FI_MSG_ERROR_PARSING;
		}

		// fill the dib with the decoded data

		const BYTE *src_bitmap = output_buffer->u.RGBA.rgba;
		const unsigned src_pitch = (unsigned)output_buffer->u.RGBA.stride;

		switch(bpp) {
			case 24:
				for(unsigned y = 0; y < height; y++) {
					const BYTE *src_bits = src_bitmap + y * src_pitch;						
					BYTE *dst_bits = (BYTE*)FreeImage_GetScanLine(dib, height-1-y);
					for(unsigned x = 0; x < width; x++) {
						dst_bits[FI_RGBA_BLUE]	= src_bits[0];	// B
						dst_bits[FI_RGBA_GREEN]	= src_bits[1];	// G
						dst_bits[FI_RGBA_RED]	= src_bits[2];	// R
						src_bits += 3;
						dst_bits += 3;
					}
				}
				break;
			case 32:
				for(unsigned y = 0; y < height; y++) {
					const BYTE *src_bits = src_bitmap + y * src_pitch;						
					BYTE *dst_bits = (BYTE*)FreeImage_GetScanLine(dib, height-1-y);
					for(unsigned x = 0; x < width; x++) {
						dst_bits[FI_RGBA_BLUE]	= src_bits[0];	// B
						dst_bits[FI_RGBA_GREEN]	= src_bits[1];	// G
						dst_bits[FI_RGBA_RED]	= src_bits[2];	// R
						dst_bits[FI_RGBA_ALPHA]	= src_bits[3];	// A
						src_bits += 4;
						dst_bits += 4;
					}
				}
				break;
		}

		// Free the decoder
		WebPFreeDecBuffer(output_buffer);

		return dib;

	} catch (const char *text) {
		if(dib) {
			FreeImage_Unload(dib);
		}
		WebPFreeDecBuffer(output_buffer);

		if(NULL != text) {
			FreeImage_OutputMessageProc(s_format_id, text);
		}

		return NULL;
	}
}

static FIBITMAP * DLL_CALLCONV
Load(FreeImageIO *io, fi_handle handle, int page, int flags, void *data) {
	WebPMux *mux = NULL;
	WebPMuxFrameInfo webp_frame = { 0 };	// raw image
	WebPData color_profile;	// ICC raw data
	WebPData xmp_metadata;	// XMP raw data
	WebPData exif_metadata;	// EXIF raw data