Don't duplicate the preserve ratio code between svg tag and surface

cairosvg/helpers.py

@@ -113,24 +113,16 @@ def point_angle(cx, cy, px, py):
     return atan2(py - cy, px - cx)
 
 
-def preserved_ratio(node):
-    """Return whether we must preserve the ratio."""
-    return node.get('preserveAspectRatio', 'xMidYMid').split(' ')[0] != 'none'
-
-
 def preserve_ratio(surface, node):
     """Manage the ratio preservation."""
     if node.tag == 'marker':
         width = size(surface, node.get('markerWidth', '3'), 'x')
         height = size(surface, node.get('markerHeight', '3'), 'y')
         _, _, viewbox = node_format(surface, node)
         viewbox_width, viewbox_height = viewbox[2:]
-    elif node.tag in ('svg', 'image'):
+    elif node.tag in ('svg', 'image', 'g'):
         width, height, _ = node_format(surface, node)
         viewbox_width, viewbox_height = node.image_width, node.image_height
-    else:
-        # Safety measure
-        return 1, 1, 0, 0
 
     translate_x = 0
     translate_y = 0

cairosvg/image.py

@@ -24,7 +24,7 @@
 
 from PIL import Image
 
-from .helpers import node_format, preserve_ratio, preserved_ratio, size
+from .helpers import node_format, preserve_ratio, size
 from .parser import Tree
 from .surface import cairo
 from .url import parse_url
@@ -64,9 +64,13 @@ def image(surface, node):
             unsafe=node.unsafe)
         tree_width, tree_height, viewbox = node_format(
             surface, tree, reference=False)
-        if not viewbox:
+        if viewbox:
+            tree_scale_x = tree_width / viewbox[2]
+            tree_scale_y = tree_height / viewbox[3]
+        else:
             tree_width = tree['width'] = width
             tree_height = tree['height'] = height
+            tree_scale_x = tree_scale_y = 1
         node.image_width = tree_width or width
         node.image_height = tree_height or height
         scale_x, scale_y, translate_x, translate_y = preserve_ratio(
@@ -79,11 +83,8 @@ def image(surface, node):
         # Draw image
         surface.context.save()
         surface.context.translate(x, y)
-        surface.set_context_size(
-            *node_format(surface, tree, reference=False), scale=1,
-            preserved_ratio=preserved_ratio(tree))
         surface.context.translate(*surface.context.get_current_point())
-        surface.context.scale(scale_x, scale_y)
+        surface.context.scale(scale_x * tree_scale_x, scale_y * tree_scale_y)
         surface.context.translate(translate_x, translate_y)
         surface.draw(tree)
         surface.context.restore()

cairosvg/surface.py

@@ -31,7 +31,7 @@
     parse_all_defs, pattern, prepare_filter, radial_gradient, use)
 from .helpers import (
     UNITS, PointError, apply_matrix_transform, clip_rect, node_format,
-    normalize, paint, preserved_ratio, size, transform)
+    normalize, paint, preserve_ratio, size, transform)
 from .image import image
 from .parser import Tree
 from .path import draw_markers, path
@@ -211,12 +211,7 @@ def __init__(self, tree, output, dpi, parent_surface=None,
         self.context.scale(
             self.device_units_per_user_units, self.device_units_per_user_units)
         # Initial, non-rounded dimensions
-        if output_width and output_height:
-            self.set_context_size(
-                width, height, viewbox, scale, tree)
-        else:
-            self.set_context_size(
-                width, height, viewbox, scale, preserved_ratio(tree))
+        self.set_context_size(width, height, viewbox, scale, tree)
         self.context.move_to(0, 0)
         self.draw(tree)
 
@@ -240,31 +235,34 @@ def _create_surface(self, width, height):
         cairo_surface = self.surface_class(self.output, width, height)
         return cairo_surface, width, height
 
-    def set_context_size(self, width, height, viewbox, scale, preserved_ratio):
+    def set_context_size(self, width, height, viewbox, scale, tree):
         """Set the Cairo context size, set the SVG viewport size."""
         if viewbox:
-            x, y, x_size, y_size = viewbox
-            self.context_width, self.context_height = x_size, y_size
-            x_ratio, y_ratio = width / x_size, height / y_size
+            rect_x, rect_y = viewbox[0:2]
+            tree.image_width = viewbox[2]
+            tree.image_height = viewbox[3]
+        else:
+            rect_x, rect_y = 0, 0
+            tree.image_width = width
+            tree.image_height = height
+
+        scale_x, scale_y, translate_x, translate_y = preserve_ratio(self, tree)
+        rect_x, rect_y = rect_x * scale_x, rect_y * scale_y
+        rect_width, rect_height = width, height
+        self.context.translate(*self.context.get_current_point())
+        self.context.translate(-rect_x, -rect_y)
+        if tree.get('overflow', 'hidden') != 'visible':
+            self.context.rectangle(rect_x, rect_y, rect_width, rect_height)
+            self.context.clip()
+        self.context.scale(scale_x, scale_y)
+        self.context.translate(translate_x, translate_y)
+        self.context_width = rect_width / scale_x
+        self.context_height = rect_height / scale_y
+
+        if scale != 1:
             matrix = cairo.Matrix()
-            if preserved_ratio and x_ratio > y_ratio:
-                matrix.translate((width - x_size * y_ratio) / 2, 0)
-                matrix.scale(y_ratio, y_ratio)
-                matrix.translate(-x / x_ratio * y_ratio, -y)
-            elif preserved_ratio and x_ratio < y_ratio:
-                matrix.translate(0, (height - y_size * x_ratio) / 2)
-                matrix.scale(x_ratio, x_ratio)
-                matrix.translate(-x, -y / y_ratio * x_ratio)
-            else:
-                matrix.scale(x_ratio, y_ratio)
-                matrix.translate(-x, -y)
+            matrix.scale(scale, scale)
             apply_matrix_transform(self, matrix)
-        else:
-            self.context_width, self.context_height = width, height
-            if scale != 1:
-                matrix = cairo.Matrix()
-                matrix.scale(scale, scale)
-                apply_matrix_transform(self, matrix)
 
     def finish(self):
         """Read the surface content."""

cairosvg/svg.py

@@ -19,32 +19,11 @@
 
 """
 
-from .helpers import node_format, preserve_ratio
+from .helpers import node_format
 
 
 def svg(surface, node):
     """Draw a svg ``node``."""
-    width, height, viewbox = node_format(surface, node)
-    if viewbox:
-        rect_x, rect_y = viewbox[0:2]
-        node.image_width = viewbox[2]
-        node.image_height = viewbox[3]
-    else:
-        rect_x, rect_y = 0, 0
-        node.image_width = width
-        node.image_height = height
-
-    if node.parent is None:
-        return
-
-    scale_x, scale_y, translate_x, translate_y = preserve_ratio(surface, node)
-    rect_x, rect_y = rect_x * scale_x, rect_y * scale_y
-    rect_width, rect_height = width, height
-    surface.context.translate(*surface.context.get_current_point())
-    surface.context.translate(-rect_x, -rect_y)
-    if node.get('overflow', 'hidden') != 'visible':
-        surface.context.rectangle(rect_x, rect_y, rect_width, rect_height)
-        surface.context.clip()
-    surface.context.scale(scale_x, scale_y)
-    surface.context.translate(translate_x, translate_y)
-    surface.context_width, surface.context_height = rect_width, rect_height
+    if node.parent is not None:
+        width, height, viewbox = node_format(surface, node)
+        surface.set_context_size(width, height, viewbox, 1, node)