Fetch background images early

This removes the need to have a reference to the image cache
in draw.py

weasyprint/css/properties.py

@@ -24,6 +24,7 @@
     'background_attachment': 'scroll',
     'background_color': COLOR_KEYWORDS['transparent'],
     'background_image': 'none',
+    '_fetched_background_image': None,  # internal, image cache
     'background_position': (Dimension(0, '%'), Dimension(0, '%')),
     'background_repeat': 'repeat',
     'background_clip': 'border-box',  # CSS3
@@ -262,4 +263,4 @@
 
 BACKGROUND_INITIAL = dict(
     (name, value) for name, value in INITIAL_VALUES.items()
-    if name.startswith('background'))
+    if 'background' in name)

weasyprint/document.py

@@ -50,8 +50,7 @@ def render_pages(self):
 
     def draw_page(self, page, context):
         """Draw page on context at scale cairo device units per CSS pixel."""
-        return draw.draw_page(page, context, self.enable_hinting,
-                              self.get_image_from_uri)
+        return draw.draw_page(page, context, self.enable_hinting)
 
     def get_png_surfaces(self, resolution=None):
         """Yield (width, height, image_surface) tuples, one for each page."""

weasyprint/draw.py

@@ -51,39 +51,31 @@ def lighten(color, offset):
         color.alpha)
 
 
-def draw_page(page, context, enable_hinting, get_image_from_uri):
+def draw_page(page, context, enable_hinting):
     """Draw the given PageBox."""
     stacking_context = StackingContext.from_page(page)
     draw_box_background(
-        context, stacking_context.page, stacking_context.box, enable_hinting,
-        get_image_from_uri)
-    draw_canvas_background(context, page, enable_hinting, get_image_from_uri)
+        context, stacking_context.page, stacking_context.box, enable_hinting)
+    draw_canvas_background(context, page, enable_hinting)
     draw_border(context, page, enable_hinting)
-    draw_stacking_context(context, stacking_context, enable_hinting,
-                          get_image_from_uri)
+    draw_stacking_context(context, stacking_context, enable_hinting)
 
 
-def draw_box_background_and_border(context, page, box, enable_hinting,
-                                   get_image_from_uri):
-    draw_box_background(context, page, box, enable_hinting, get_image_from_uri)
+def draw_box_background_and_border(context, page, box, enable_hinting):
+    draw_box_background(context, page, box, enable_hinting)
     if not isinstance(box, boxes.TableBox):
         draw_border(context, box, enable_hinting)
     else:
         for column_group in box.column_groups:
-            draw_box_background(context, page, column_group, enable_hinting,
-                                get_image_from_uri)
+            draw_box_background(context, page, column_group, enable_hinting)
             for column in column_group.children:
-                draw_box_background(context, page, column, enable_hinting,
-                                    get_image_from_uri)
+                draw_box_background(context, page, column, enable_hinting)
         for row_group in box.children:
-            draw_box_background(context, page, row_group, enable_hinting,
-                                get_image_from_uri)
+            draw_box_background(context, page, row_group, enable_hinting)
             for row in row_group.children:
-                draw_box_background(context, page, row, enable_hinting,
-                                    get_image_from_uri)
+                draw_box_background(context, page, row, enable_hinting)
                 for cell in row.children:
-                    draw_box_background(context, page, cell, enable_hinting,
-                                        get_image_from_uri)
+                    draw_box_background(context, page, cell, enable_hinting)
         if box.style.border_collapse == 'separate':
             draw_border(context, box, enable_hinting)
             for row_group in box.children:
@@ -94,8 +86,7 @@ def draw_box_background_and_border(context, page, box, enable_hinting,
             draw_collapsed_borders(context, box, enable_hinting)
 
 
-def draw_stacking_context(context, stacking_context, enable_hinting,
-                          get_image_from_uri):
+def draw_stacking_context(context, stacking_context, enable_hinting):
     """Draw a ``stacking_context`` on ``context``."""
     # See http://www.w3.org/TR/CSS2/zindex.html
     with stacked(context):
@@ -133,38 +124,32 @@ def draw_stacking_context(context, stacking_context, enable_hinting,
                             boxes.InlineBlockBox)):
             # The canvas background was removed by set_canvas_background
             draw_box_background_and_border(
-                context, stacking_context.page, box, enable_hinting,
-                get_image_from_uri)
+                context, stacking_context.page, box, enable_hinting)
 
         # Point 3
         for child_context in stacking_context.negative_z_contexts:
-            draw_stacking_context(context, child_context, enable_hinting,
-                                  get_image_from_uri)
+            draw_stacking_context(context, child_context, enable_hinting)
 
         # Point 4
         for block in stacking_context.block_level_boxes:
             draw_box_background_and_border(
-                context, stacking_context.page, block, enable_hinting,
-                get_image_from_uri)
+                context, stacking_context.page, block, enable_hinting)
 
         # Point 5
         for child_context in stacking_context.float_contexts:
-            draw_stacking_context(context, child_context, enable_hinting,
-                                  get_image_from_uri)
+            draw_stacking_context(context, child_context, enable_hinting)
 
         # Point 6
         if isinstance(box, boxes.InlineBox):
             draw_inline_level(
-                context, stacking_context.page, box,
-                enable_hinting, get_image_from_uri)
+                context, stacking_context.page, box, enable_hinting)
 
         # Point 7
         for block in [box] + stacking_context.blocks_and_cells:
             marker_box = getattr(block, 'outside_list_marker', None)
             if marker_box:
                 draw_inline_level(
-                    context, stacking_context.page, marker_box,
-                    enable_hinting, get_image_from_uri)
+                    context, stacking_context.page, marker_box, enable_hinting)
 
             if isinstance(block, boxes.ReplacedBox):
                 draw_replacedbox(context, block)
@@ -174,17 +159,15 @@ def draw_stacking_context(context, stacking_context, enable_hinting,
                         # TODO: draw inline tables
                         draw_inline_level(
                             context, stacking_context.page, child,
-                            enable_hinting, get_image_from_uri)
+                            enable_hinting)
 
         # Point 8
         for child_context in stacking_context.zero_z_contexts:
-            draw_stacking_context(context, child_context, enable_hinting,
-                                  get_image_from_uri)
+            draw_stacking_context(context, child_context, enable_hinting)
 
         # Point 9
         for child_context in stacking_context.positive_z_contexts:
-            draw_stacking_context(context, child_context, enable_hinting,
-                                  get_image_from_uri)
+            draw_stacking_context(context, child_context, enable_hinting)
 
         # Point 10
         draw_outlines(context, box, enable_hinting)
@@ -227,7 +210,7 @@ def background_positioning_area(page, box, style):
         return box_rectangle(box, box.style.background_origin)
 
 
-def draw_canvas_background(context, page, enable_hinting, get_image_from_uri):
+def draw_canvas_background(context, page, enable_hinting):
     if not page.children or isinstance(page.children[0], boxes.MarginBox):
         # Skip the canvas background on content-empty pages
         # TODO: remove this when content empty pages still get boxes
@@ -238,12 +221,10 @@ def draw_canvas_background(context, page, enable_hinting, get_image_from_uri):
     draw_background(context, style,
         painting_area=box_rectangle(page, 'padding-box'),
         positioning_area=background_positioning_area(page, root_box, style),
-        enable_hinting=enable_hinting,
-        get_image_from_uri=get_image_from_uri)
+        enable_hinting=enable_hinting)
 
 
-def draw_box_background(context, page, box, enable_hinting,
-                        get_image_from_uri):
+def draw_box_background(context, page, box, enable_hinting):
     """Draw the box background color and image to a ``cairo.Context``."""
     if box.style.visibility == 'hidden':
         return
@@ -254,8 +235,7 @@ def draw_box_background(context, page, box, enable_hinting,
     draw_background(
         context, box.style, painting_area,
         positioning_area=background_positioning_area(page, box, box.style),
-        enable_hinting=enable_hinting,
-        get_image_from_uri=get_image_from_uri)
+        enable_hinting=enable_hinting)
 
 
 def percentage(value, refer_to):
@@ -268,14 +248,10 @@ def percentage(value, refer_to):
 
 
 def draw_background(context, style, painting_area, positioning_area,
-                    enable_hinting, get_image_from_uri):
+                    enable_hinting):
     """Draw the background color and image to a ``cairo.Context``."""
     bg_color = style.background_color
-    bg_image = style.background_image
-    if bg_image == 'none':
-        image = None
-    else:
-        image = get_image_from_uri(bg_image)
+    image = style._fetched_background_image
     if bg_color.alpha == 0 and image is None:
         # No background.
         return
@@ -713,23 +689,20 @@ def draw_replacedbox(context, box):
     box.replacement = 'Removed to work around cairo’s behavior'
 
 
-def draw_inline_level(context, page, box, enable_hinting, get_image_from_uri):
+def draw_inline_level(context, page, box, enable_hinting):
     if isinstance(box, StackingContext):
         stacking_context = box
         assert isinstance(stacking_context.box, boxes.InlineBlockBox)
-        draw_stacking_context(context, stacking_context, enable_hinting,
-                              get_image_from_uri)
+        draw_stacking_context(context, stacking_context, enable_hinting)
     else:
-        draw_box_background(
-            context, page, box, enable_hinting, get_image_from_uri)
+        draw_box_background(context, page, box, enable_hinting)
         draw_border(context, box, enable_hinting)
         if isinstance(box, (boxes.InlineBox, boxes.LineBox)):
             for child in box.children:
                 if isinstance(child, boxes.TextBox):
                     draw_text(context, child, enable_hinting)
                 else:
-                    draw_inline_level(context, page, child, enable_hinting,
-                                      get_image_from_uri)
+                    draw_inline_level(context, page, child, enable_hinting)
         elif isinstance(box, boxes.InlineReplacedBox):
             draw_replacedbox(context, box)
         else:

weasyprint/formatting_structure/build.py

@@ -61,7 +61,7 @@ def build_formatting_structure(element_tree, style_for, get_image_from_uri):
     return box
 
 
-def make_box(element_tag, sourceline, style, content):
+def make_box(element_tag, sourceline, style, content, get_image_from_uri):
     if (style.display in ('table', 'inline-table')
             and style.border_collapse == 'collapse'):
         # Padding do not apply
@@ -72,6 +72,10 @@ def make_box(element_tag, sourceline, style, content):
         for side in ['top', 'bottom', 'left', 'right']:
             style['margin_' + side] = ZERO_PIXELS
 
+    # Do this early so that draw.py does not need a reference to the cache.
+    style._fetched_background_image = (
+        get_image_from_uri(style.background_image)
+        if style.background_image != 'none' else None)
     return BOX_TYPE_FROM_DISPLAY[style.display](element_tag, sourceline,
                                                 style, content)
 
@@ -112,7 +116,8 @@ def element_to_box(element, style_for, get_image_from_uri, state=None):
     if display == 'none':
         return []
 
-    box = make_box(element.tag, element.sourceline, style, [])
+    box = make_box(element.tag, element.sourceline, style, [],
+                   get_image_from_uri)
 
     if state is None:
         # use a list to have a shared mutable object
@@ -177,7 +182,8 @@ def pseudo_to_box(element, pseudo_type, state, style_for, get_image_from_uri):
         return
 
     box = make_box(
-        '%s:%s' % (element.tag, pseudo_type), element.sourceline, style, [])
+        '%s:%s' % (element.tag, pseudo_type), element.sourceline, style, [],
+        get_image_from_uri)
 
     quote_depth, counter_values, _counter_scopes = state
     update_counters(state, style)

weasyprint/layout/pages.py

@@ -287,6 +287,10 @@ def make_box(at_keyword, containing_block):
         style = context.style_for(page.page_type, at_keyword)
         if style is None:
             style = page.style.inherit_from()
+        # Do this early so that draw.py does not need a reference to the cache.
+        style._fetched_background_image = (
+            get_image_from_uri(style.background_image)
+            if style.background_image != 'none' else None)
         box = boxes.MarginBox(at_keyword, style)
         # Empty boxes should not be generated, but they may be needed for
         # the layout of their neighbors.
@@ -470,6 +474,10 @@ def make_page(context, root_box, page_type, resume_at, content_empty):
     style = context.style_for(page_type)
     # Propagated from the root or <body>.
     style.overflow = root_box.viewport_overflow
+    # Do this early so that draw.py does not need a reference to the cache.
+    style._fetched_background_image = (
+        get_image_from_uri(style.background_image)
+        if style.background_image != 'none' else None)
     page = boxes.PageBox(page_type, style)
 
     device_size = page.style.size