C++ (Cpp) Canvas::GetPixelByteSize Examples

Example #1

File: uitexloader.cpp Project: highfestiva/life

TEXLoader::IoStatus TEXLoader::ReadJpeg(Canvas& canvas) {
	unsigned size;
	load_file_->Read(size);

	jpeg_decompress_struct _c_info;
	jpeg_error_mgr j_err;

	_c_info.err = jpeg_std_error(&j_err);
	jpeg_create_decompress(&_c_info);

	InitSourceManager(&_c_info);

	if (jpeg_read_header(&_c_info, TRUE) != JPEG_HEADER_OK) {
		jpeg_destroy_decompress(&_c_info);
		return kStatusReadHeaderError;
	}

	if (jpeg_start_decompress(&_c_info) != TRUE) {
		jpeg_destroy_decompress(&_c_info);
		return kStatusReadPictureError;
	}

	if (_c_info.output_components == 1) {
		// Create grayscale palette.
		Color palette[256];
		for (int i = 0; i < 256; i++) {
			palette[i].Set(i, i, i, i);
		}
		canvas.SetPalette(palette);
	}

	uint8* buffer = (uint8*)canvas.GetBuffer();
	int row_stride = canvas.GetPitch() * canvas.GetPixelByteSize();
	int scan_lines = canvas.GetHeight();

	JSAMPROW offset[1];
	offset[0] = buffer;

	for (int i = 0; i < scan_lines; i++) {
		jpeg_read_scanlines(&_c_info, offset, 1);
		offset[0] += row_stride;
	}

	jpeg_finish_decompress(&_c_info);
	jpeg_destroy_decompress(&_c_info);

	load_file_->SeekCur(size);

	return kStatusSuccess;
}