Fix dpi detection in tight_bbox (fixes #2586).

pwuertz · pwuertz · commit c54e2ba6895d · 2013-12-18T17:18:55.000+01:00
diff --git a/doc/api/api_changes.rst b/doc/api/api_changes.rst
@@ -119,6 +119,12 @@ original location:
 * Removed the class `FigureManagerQTAgg` and deprecated `NavigationToolbar2QTAgg`
   which will be removed in 1.5.
 
+* The function signatures of `tight_bbox.adjust_bbox` and
+  `tight_bbox.process_figure_for_rasterizing` have been changed. A new
+  `fixed_dpi` parameter allows for overriding the `figure.dpi` setting
+  instead of trying to deduce the intended behaviour from the file format.
+
+
 .. _changes_in_1_3:
 
 
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -1625,6 +1625,7 @@ class FigureCanvasBase(object):
     ]
 
     supports_blit = True
+    fixed_dpi = None
 
     filetypes = _default_filetypes
     if _has_pil:
@@ -2171,8 +2172,8 @@ def print_figure(self, filename, dpi=None, facecolor='w', edgecolor='w',
 
                 bbox_inches = bbox_inches.padded(pad)
 
-            restore_bbox = tight_bbox.adjust_bbox(self.figure, format,
-                                                  bbox_inches)
+            restore_bbox = tight_bbox.adjust_bbox(self.figure, bbox_inches,
+                                                  canvas.fixed_dpi)
 
             _bbox_inches_restore = (bbox_inches, restore_bbox)
         else:
diff --git a/lib/matplotlib/backends/backend_mixed.py b/lib/matplotlib/backends/backend_mixed.py
@@ -93,12 +93,9 @@ def start_rasterizing(self):
 
         if self._bbox_inches_restore: # when tight bbox is used
             r = process_figure_for_rasterizing(self.figure,
-                                               self._bbox_inches_restore,
-                                               mode="png")
-
+                                               self._bbox_inches_restore)
             self._bbox_inches_restore = r
 
-
         if self._rasterizing == 0:
             self._raster_renderer = self._raster_renderer_class(
                 self._width*self.dpi, self._height*self.dpi, self.dpi)
@@ -143,5 +140,5 @@ def stop_rasterizing(self):
         if self._bbox_inches_restore:  # when tight bbox is used
             r = process_figure_for_rasterizing(self.figure,
                                                self._bbox_inches_restore,
-                                               mode="pdf")
+                                               self._figdpi)
             self._bbox_inches_restore = r
diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
@@ -2434,6 +2434,8 @@ class FigureCanvasPdf(FigureCanvasBase):
       figure - A Figure instance
     """
 
+    fixed_dpi = 72
+
     def draw(self):
         pass
 
diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
@@ -966,6 +966,8 @@ def new_figure_manager_given_figure(num, figure):
 class FigureCanvasPS(FigureCanvasBase):
     _renderer_class = RendererPS
 
+    fixed_dpi = 72
+
     def draw(self):
         pass
 
diff --git a/lib/matplotlib/backends/backend_svg.py b/lib/matplotlib/backends/backend_svg.py
@@ -1150,6 +1150,8 @@ class FigureCanvasSVG(FigureCanvasBase):
     filetypes = {'svg': 'Scalable Vector Graphics',
                  'svgz': 'Scalable Vector Graphics'}
 
+    fixed_dpi = 72
+
     def print_svg(self, filename, *args, **kwargs):
         if is_string_like(filename):
             fh_to_close = svgwriter = io.open(filename, 'w', encoding='utf-8')
diff --git a/lib/matplotlib/tight_bbox.py b/lib/matplotlib/tight_bbox.py
@@ -11,7 +11,7 @@
 from matplotlib.transforms import Bbox, TransformedBbox, Affine2D
 
 
-def adjust_bbox(fig, format, bbox_inches):
+def adjust_bbox(fig, bbox_inches, fixed_dpi=None):
     """
     Temporarily adjust the figure so that only the specified area
     (bbox_inches) is saved.
@@ -50,74 +50,31 @@ def restore_bbox():
         fig.transFigure.invalidate()
         fig.patch.set_bounds(0, 0, 1, 1)
 
-    adjust_bbox_handler = _adjust_bbox_handler_d.get(format)
-    if adjust_bbox_handler is not None:
-        adjust_bbox_handler(fig, bbox_inches)
-        return restore_bbox
+    if fixed_dpi is not None:
+        tr = Affine2D().scale(fixed_dpi)
+        dpi_scale = fixed_dpi / fig.dpi
     else:
-        warnings.warn("bbox_inches option for %s backend is not "
-                      "implemented yet." % (format))
-        return None
-
-
-def adjust_bbox_png(fig, bbox_inches):
-    """
-    adjust_bbox for png (Agg) format
-    """
-
-    tr = fig.dpi_scale_trans
-
-    _bbox = TransformedBbox(bbox_inches,
-                            tr)
-    x0, y0 = _bbox.x0, _bbox.y0
-    fig.bbox_inches = Bbox.from_bounds(0, 0,
-                                       bbox_inches.width,
-                                       bbox_inches.height)
-
-    x0, y0 = _bbox.x0, _bbox.y0
-    w1, h1 = fig.bbox.width, fig.bbox.height
-    fig.transFigure._boxout = Bbox.from_bounds(-x0, -y0,
-                                                       w1, h1)
-    fig.transFigure.invalidate()
-
-    fig.bbox = TransformedBbox(fig.bbox_inches, tr)
-
-    fig.patch.set_bounds(x0 / w1, y0 / h1,
-                         fig.bbox.width / w1, fig.bbox.height / h1)
-
-
-def adjust_bbox_pdf(fig, bbox_inches):
-    """
-    adjust_bbox for pdf & eps format
-    """
-
-    if fig._cachedRenderer.__class__.__name__ == "RendererPgf":
         tr = Affine2D().scale(fig.dpi)
-        f = 1.
-    else:
-        tr = Affine2D().scale(72)
-        f = 72. / fig.dpi
+        dpi_scale = 1.
 
     _bbox = TransformedBbox(bbox_inches, tr)
 
     fig.bbox_inches = Bbox.from_bounds(0, 0,
-                                       bbox_inches.width,
-                                       bbox_inches.height)
+                                       bbox_inches.width, bbox_inches.height)
     x0, y0 = _bbox.x0, _bbox.y0
-    w1, h1 = fig.bbox.width * f, fig.bbox.height * f
-    fig.transFigure._boxout = Bbox.from_bounds(-x0, -y0,
-                                                       w1, h1)
+    w1, h1 = fig.bbox.width * dpi_scale, fig.bbox.height * dpi_scale
+    fig.transFigure._boxout = Bbox.from_bounds(-x0, -y0, w1, h1)
     fig.transFigure.invalidate()
 
     fig.bbox = TransformedBbox(fig.bbox_inches, tr)
 
     fig.patch.set_bounds(x0 / w1, y0 / h1,
                          fig.bbox.width / w1, fig.bbox.height / h1)
 
+    return restore_bbox
 
-def process_figure_for_rasterizing(figure,
-                                   bbox_inches_restore, mode):
 
+def process_figure_for_rasterizing(fig, bbox_inches_restore, fixed_dpi=None):
     """
     This need to be called when figure dpi changes during the drawing
     (e.g., rasterizing). It recovers the bbox and re-adjust it with
@@ -126,14 +83,6 @@ def process_figure_for_rasterizing(figure,
 
     bbox_inches, restore_bbox = bbox_inches_restore
     restore_bbox()
-    r = adjust_bbox(figure, mode,
-                    bbox_inches)
+    r = adjust_bbox(figure, bbox_inches, fixed_dpi)
 
     return bbox_inches, r
-
-
-_adjust_bbox_handler_d = {}
-for format in ["png", "raw", "rgba", "jpg", "jpeg", "tiff"]:
-    _adjust_bbox_handler_d[format] = adjust_bbox_png
-for format in ["pgf", "pdf", "eps", "svg", "svgz"]:
-    _adjust_bbox_handler_d[format] = adjust_bbox_pdf
