+
+
+class Memory
+{
+public:
+ Memory ()
+ : data(0)
+ , size(0)
+ {}
+
+ ~Memory ()
+ {
+ free (data);
+ }
+
+ uint8_t* data;
+ size_t size;
+};
+
+
+static void
+png_write_data (png_structp png_ptr, png_bytep data, png_size_t length)
+{
+ auto mem = reinterpret_cast<Memory*>(png_get_io_ptr(png_ptr));
+ size_t size = mem->size + length;
+
+ if (mem->data) {
+ mem->data = reinterpret_cast<uint8_t*>(realloc(mem->data, size));
+ } else {
+ mem->data = reinterpret_cast<uint8_t*>(malloc(size));
+ }
+
+ if (!mem->data) {
+ throw EncodeError (N_("could not allocate memory for PNG"));
+ }
+
+ memcpy (mem->data + mem->size, data, length);
+ mem->size += length;
+}
+
+
+static void
+png_flush (png_structp)
+{
+
+}
+
+
+static void
+png_error_fn (png_structp png_ptr, char const * message)
+{
+ reinterpret_cast<Image*>(png_get_error_ptr(png_ptr))->png_error (message);
+}
+
+
+void
+Image::png_error (char const * message)
+{
+ throw EncodeError (String::compose ("Error during PNG write: %1", message));
+}
+
+
+dcp::ArrayData
+Image::as_png () const
+{
+ DCPOMATIC_ASSERT (bytes_per_pixel(0) == 4);
+ DCPOMATIC_ASSERT (planes() == 1);
+ if (pixel_format() != AV_PIX_FMT_RGBA) {
+ return convert_pixel_format(dcp::YUVToRGB::REC709, AV_PIX_FMT_RGBA, Image::Alignment::PADDED, false)->as_png();
+ }
+
+ /* error handling? */
+ png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, reinterpret_cast<void*>(const_cast<Image*>(this)), png_error_fn, 0);
+ if (!png_ptr) {
+ throw EncodeError (N_("could not create PNG write struct"));
+ }
+
+ Memory state;
+
+ png_set_write_fn (png_ptr, &state, png_write_data, png_flush);
+
+ png_infop info_ptr = png_create_info_struct(png_ptr);
+ if (!info_ptr) {
+ png_destroy_write_struct (&png_ptr, &info_ptr);
+ throw EncodeError (N_("could not create PNG info struct"));
+ }
+
+ png_set_IHDR (png_ptr, info_ptr, size().width, size().height, 8, PNG_COLOR_TYPE_RGBA, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+
+ png_byte ** row_pointers = reinterpret_cast<png_byte **>(png_malloc(png_ptr, size().height * sizeof(png_byte *)));
+ for (int i = 0; i < size().height; ++i) {
+ row_pointers[i] = (png_byte *) (data()[0] + i * stride()[0]);
+ }
+
+ png_write_info (png_ptr, info_ptr);
+ png_write_image (png_ptr, row_pointers);
+ png_write_end (png_ptr, info_ptr);
+
+ png_destroy_write_struct (&png_ptr, &info_ptr);
+ png_free (png_ptr, row_pointers);
+
+ return dcp::ArrayData (state.data, state.size);
+}
+
+
+void
+Image::video_range_to_full_range ()
+{
+ switch (_pixel_format) {
+ case AV_PIX_FMT_RGB24:
+ {
+ float const factor = 256.0 / 219.0;
+ uint8_t* p = data()[0];
+ int const lines = sample_size(0).height;
+ for (int y = 0; y < lines; ++y) {
+ uint8_t* q = p;
+ for (int x = 0; x < line_size()[0]; ++x) {
+ *q = clamp(lrintf((*q - 16) * factor), 0L, 255L);
+ ++q;
+ }
+ p += stride()[0];
+ }
+ break;
+ }
+ case AV_PIX_FMT_RGB48LE:
+ {
+ float const factor = 65536.0 / 56064.0;
+ uint16_t* p = reinterpret_cast<uint16_t*>(data()[0]);
+ int const lines = sample_size(0).height;
+ for (int y = 0; y < lines; ++y) {
+ uint16_t* q = p;
+ int const line_size_pixels = line_size()[0] / 2;
+ for (int x = 0; x < line_size_pixels; ++x) {
+ *q = clamp(lrintf((*q - 4096) * factor), 0L, 65535L);
+ ++q;
+ }
+ p += stride()[0] / 2;
+ }
+ break;
+ }
+ case AV_PIX_FMT_GBRP12LE:
+ {
+ float const factor = 4096.0 / 3504.0;
+ for (int c = 0; c < 3; ++c) {
+ uint16_t* p = reinterpret_cast<uint16_t*>(data()[c]);
+ int const lines = sample_size(c).height;
+ for (int y = 0; y < lines; ++y) {
+ uint16_t* q = p;
+ int const line_size_pixels = line_size()[c] / 2;
+ for (int x = 0; x < line_size_pixels; ++x) {
+ *q = clamp(lrintf((*q - 256) * factor), 0L, 4095L);
+ ++q;
+ }
+ }
+ }
+ break;
+ }
+ default:
+ throw PixelFormatError ("video_range_to_full_range()", _pixel_format);
+ }
+}
+