Add dpi to saved PNGs, and scale images in reports

orangewidget/io.py

@@ -130,8 +130,7 @@ def save_pyqtgraph():
  exporter = cls._get_exporter()
  scene = object.scene()
  if scene is None:
- cls._export(exporter(scene), filename)
- return
+ return cls._export(exporter(scene), filename)
  views = scene.views()
  if views:
  # preserve scene rect and background brush
@@ -141,22 +140,21 @@ def save_pyqtgraph():
  view = scene.views()[0]
  scene.setSceneRect(view.sceneRect())
  scene.setBackgroundBrush(effective_background(scene, view))
- cls._export(exporter(scene), filename)
+ return cls._export(exporter(scene), filename)
  finally:
  # reset scene rect and background brush
  scene.setBackgroundBrush(backgroundbrush)
  scene.setSceneRect(scenerect)
  else:
- cls._export(exporter(scene), filename)
+ return cls._export(exporter(scene), filename)
 
  def save_scene():
  assert isinstance(object, QGraphicsScene)
  ratio = get_scene_pixel_ratio(object)
  views = object.views()
  if not views:
  rect = object.itemsBoundingRect()
- _render(rect, ratio, rect.size(), object)
- return
+ return _render(rect, ratio, rect.size(), object)
 
  # Pick the first view. If there's a widget with multiple views that
  # cares which one is used, it must set graph_name to view, not scene
@@ -166,11 +164,11 @@ def save_scene():
  source_rect = QRect(
  int(target_rect.x()), int(target_rect.y()),
  int(target_rect.width()), int(target_rect.height()))
- _render(source_rect, ratio, target_rect.size(), view)
+ return _render(source_rect, ratio, target_rect.size(), view)
 
  def save_widget():
  assert isinstance(object, QWidget)
- _render(object.rect(), object.devicePixelRatio(), object.size(),
+ return _render(object.rect(), object.devicePixelRatio(), object.size(),
  object)
 
  def _render(
@@ -203,13 +201,16 @@ def _render(
  # not a core dump
  painter.end()
  cls._save_buffer(buffer, filename)
+ return dict(width=buffer.size().width(),
+ height=buffer.size().height(),
+ pixel_ratio=pixel_ratio)
 
  if isinstance(object, GraphicsItem):
- save_pyqtgraph()
+ return save_pyqtgraph()
  elif isinstance(object, QGraphicsScene):
- save_scene()
+ return save_scene()
  elif isinstance(object, QWidget): # this includes QGraphicsView
- save_widget()
+ return save_widget()
  else:
  raise TypeError(f"{cls.__name__} "
  f"cannot imagine {type(object).__name__}")
@@ -218,7 +219,7 @@ def _render(
  def write(cls, filename, scene):
  if type(scene) == dict:
  scene = scene['scene']
- cls.write_image(filename, scene)
+ return cls.write_image(filename, scene)
 
  @classproperty
  def img_writers(cls): # type: () -> Mapping[str, Type[ImgFormat]]
@@ -260,7 +261,11 @@ def _setup_painter(cls, painter, object, source_rect, buffer):
 
  @staticmethod
  def _save_buffer(buffer, filename):
- buffer.save(filename, "png")
+ image = buffer.toImage()
+ dpm = 2835 * image.devicePixelRatio()
+ image.setDotsPerMeterX(dpm)
+ image.setDotsPerMeterY(dpm)
+ image.save(filename, "png")
 
  @staticmethod
  def _get_exporter():
@@ -300,6 +305,9 @@ def export(self, fileName=None, toBytes=False, copy=False):
  QtGui.QImage.Format.Format_ARGB32)
  self.png.fill(self.params['background'])
  self.png.setDevicePixelRatio(self.ratio)
+ dpm = 2835 * self.ratio
+ self.png.setDotsPerMeterX(dpm)
+ self.png.setDotsPerMeterY(dpm)
 
  ## set resolution of image:
  origTargetRect = self.getTargetRect()
@@ -348,6 +356,9 @@ def export(self, fileName=None, toBytes=False, copy=False):
  def _export(exporter, filename):
  buffer = exporter.export(toBytes=True)
  buffer.save(filename, "png")
+ return dict(width=buffer.size().width(),
+ height=buffer.size().height(),
+ pixel_ratio=buffer.devicePixelRatio())
 
 
 class ClipboardFormat(PngFormat):

orangewidget/report/report.py

@@ -627,13 +627,17 @@ def get_html_img(
  byte_array = QByteArray()
  filename = QBuffer(byte_array)
  filename.open(QIODevice.WriteOnly)
- PngFormat.write(filename, scene)
+ img_data = PngFormat.write(filename, scene)
+
  img_encoded = byte_array.toBase64().data().decode("utf-8")
- return '<img {} src="data:image/png;base64,{}"/>'.format(
- ("" if max_height is None
- else 'style="max-height: {}px"'.format(max_height)),
- img_encoded
- )
+
+ style_opts = []
+ if max_height is not None:
+ style_opts.append(f"max-height: {max_height}px")
+ if img_data is not None and (ratio := img_data.get("pixel_ratio", 1)) != 1:
+ style_opts.append(f"zoom: {1 / ratio:.1f}")
+ style = f' style="{"; ".join(style_opts)}"' if style_opts else ''
+ return f'<img{style} src="data:image/png;base64,{img_encoded}"/>'
 
 
 def get_icon_html(icon: QIcon, size: QSize) -> str: