renderVideo function

void renderVideo(Widget app, { Directory? directory, })

Implementation

void renderVideo(
  Widget app, {
  Directory? directory,
}) {
  final effectiveDirectory = directory ?? _defaultDirectory();
  testWidgets(
    'Rendering video',
    (tester) async {
      final binding = TestWidgetsFlutterBinding.ensureInitialized();
      await binding.runAsync<String?>(() async {
        await loadFonts();
        return null;
      });
      final controller = RenderFootageController();
      final footage = Footage(
        controller: controller,
        child: app,
      );

      print('Loading composition...');
      while (controller.config == null) {
        await tester.pumpWidget(footage);
      }

      final config = controller.config!;
      binding.window.devicePixelRatioTestValue = 1.0;
      binding.window.physicalSizeTestValue = Size(
        config.width.toDouble(),
        config.height.toDouble(),
      );

      print('Creating directory $effectiveDirectory...');
      effectiveDirectory.createSync(recursive: true);

      print('Creating config...');
      final configFile = File(join(effectiveDirectory.path, 'config.json'));
      final configJson = jsonEncode({
        'width': config.width,
        'height': config.height,
        'fps': config.fps,
        'durationInFrames': config.durationInFrames,
      });

      print('Config : $configJson');
      configFile.writeAsStringSync(configJson);

      for (var frame = 0; frame < config.durationInFrames; frame++) {
        print('Frame $frame/${config.durationInFrames}');
        controller.updateFrame(frame);
        await tester.pumpWidget(footage);
        final imageFuture = captureImage(tester.allElements.first);

        await binding.runAsync<String?>(() async {
          final image = await imageFuture;

          final bytes = await image.toByteData(format: ui.ImageByteFormat.png);
          if (bytes == null) {
            return 'could not encode screenshot.';
          }
          final frameFile =
              File(join(effectiveDirectory.path, 'frames', '$frame.png'));
          print('Saving frame to $frameFile');
          try {
            await frameFile.parent.create(recursive: true);
            await frameFile.writeAsBytes(bytes.buffer.asInt8List(),
                flush: true);
          } catch (e) {
            print('Failed: $e');
          }
          return null;
        });
      }
    },
  );
}