Fix the shirk to fit agorithm

weasyprint/layout/preferred.py

@@ -14,10 +14,39 @@ from __future__ import division, unicode_literals
 
 import cairo
 
+from ..css.values import get_percentage_value
 from ..formatting_structure import boxes
 from ..text import TextFragment
-from .inlines import replaced_box_width
-from .percentages import resolve_percentages
+
+
+def variable_and_fixed_widths(box, width=None):
+    """Return ``(variable_ratio, fixed_width)`` of ``box``.
+
+    ``'auto'`` margins are ignored. ``'auto'`` width is not allowed.
+
+    """
+    if width is None:
+        width = box.style.width
+
+    assert width is not 'auto'
+
+    if isinstance(width, (int, float)):
+        fixed_width = width
+        variable_ratio = 0
+    else:
+        fixed_width = 0
+        variable_ratio = get_percentage_value(width) / 100.
+
+    for value in ('margin_left', 'margin_right',
+                  'border_left_width', 'border_right_width',
+                  'padding_left', 'padding_right'):
+        style_value = box.style[value]
+        if isinstance(style_value, (int, float)):
+            fixed_width += style_value
+        elif style_value != 'auto':
+            variable_ratio += get_percentage_value(style_value) / 100.
+
+    return variable_ratio, fixed_width
 
 
 def shrink_to_fit(box):
@@ -25,84 +54,79 @@ def shrink_to_fit(box):
     return preferred_width(box), preferred_mimimum_width(box)
 
 
-def preferred_mimimum_width(box, containing_block=None):
+def preferred_mimimum_width(box):
     """Return the preferred minimum width for ``box``.
 
     This is the width by breaking at every line-break opportunity.
 
     """
     if isinstance(box, boxes.BlockContainerBox):
-        return block_preferred_minimum_width(box, containing_block)
+        return block_preferred_minimum_width(box)
     elif isinstance(box, (boxes.InlineBox, boxes.LineBox)):
-        return inline_preferred_minimum_width(box, containing_block)
+        return inline_preferred_minimum_width(box)
     else:
         raise TypeError(
             'Preferred minimum width for %s not handled yet' %
             type(box).__name__)
 
 
-def preferred_width(box, containing_block=None):
+def preferred_width(box):
     """Return the preferred width for ``box``.
 
     This is the width by only breaking at forced line breaks.
 
     """
     if isinstance(box, boxes.BlockContainerBox):
-        return block_preferred_width(box, containing_block)
+        return block_preferred_width(box)
     elif isinstance(box, (boxes.InlineBox, boxes.LineBox)):
-        return inline_preferred_width(box, containing_block)
+        return inline_preferred_width(box)
     else:
         raise TypeError(
             'Preferred width for %s not handled yet' % type(box).__name__)
 
 
-def block_preferred_minimum_width(box, containing_block=None):
+def _block_preferred_width(box, function):
+    """Helper to create ``block_preferred_*_width.``"""
+    if not isinstance(box.style.width, (int, float)):
+        # % and 'auto' width
+        if box.children:
+            width = max(function(child) for child in box.children)
+        else:
+            width = 0
+    else:
+        width = None
+
+    variable_ratio, fixed_width = variable_and_fixed_widths(box, width)
+    if variable_ratio < 1:
+        return fixed_width / (1 - variable_ratio)
+    else:
+        return 0
+
+
+def block_preferred_minimum_width(box):
     """Return the preferred minimum width for a ``BlockBox``."""
-    if box.style['width'] == 'auto':
-        if box.children:
-            return max(
-                preferred_mimimum_width(child, box)
-                for child in box.children)
-        else:
-            return 0
-    elif isinstance(box.style['width'], (int, float)):
-        assert containing_block
-        resolve_percentages(box, containing_block)
-        return box.margin_width()
-    else:
-        # TODO: find a value for % width
-        raise TypeError('Width %s is unknown' % box.style['width'])
+    return _block_preferred_width(box, preferred_mimimum_width)
 
 
-def block_preferred_width(box, containing_block=None):
+def block_preferred_width(box):
     """Return the preferred width for a ``BlockBox``."""
-    if box.style['width'] == 'auto':
-        if box.children:
-            return max(
-                preferred_width(child, box) for child in box.children)
-        else:
-            return 0
-    elif isinstance(box.style['width'], (int, float)):
-        assert containing_block
-        resolve_percentages(box, containing_block)
-        return box.margin_width()
-    else:
-        # TODO: find a value for % width
-        raise TypeError('Width %s is unknown' % box.style['width'])
+    return _block_preferred_width(box, preferred_width)
 
 
-def inline_preferred_minimum_width(box, containing_block=None):
+def inline_preferred_minimum_width(box):
     """Return the preferred minimum width for an ``InlineBox``.
 
     *Warning:* only TextBox and InlineReplacedBox children are supported
-    for now. (No recursive InlineBox childdren.)
+    for now. (No recursive InlineBox children.)
 
     """
     widest_line = 0
     for child in box.children:
-        if isinstance(child, boxes.AtomicInlineLevelBox):
+        if isinstance(child, boxes.InlineReplacedBox):
             # Images are on their own line
             current_line = replaced_preferred_width(child)
+        elif isinstance(child, boxes.InlineBlockBox):
+            current_line = block_preferred_minimum_width(child)
         else:
             assert isinstance(child, boxes.TextBox)
             current_line = max(text_lines_width(child, width=0))
@@ -110,7 +134,7 @@ def inline_preferred_minimum_width(box, containing_block=None):
     return widest_line
 
 
-def inline_preferred_width(box, containing_block=None):
+def inline_preferred_width(box):
     """Return the preferred width for an ``InlineBox``.
 
     *Warning:* only TextBox and InlineReplacedBox children are supported
@@ -123,6 +147,8 @@ def inline_preferred_width(box, containing_block=None):
         if isinstance(child, boxes.InlineReplacedBox):
             # No line break around images
             current_line += replaced_preferred_width(child)
+        elif isinstance(child, boxes.InlineBlockBox):
+            current_line += block_preferred_width(child)
         else:
             assert isinstance(child, boxes.TextBox)
             lines = list(text_lines_width(child, width=None))
@@ -149,8 +175,14 @@ def text_lines_width(box, width):
 
 def replaced_preferred_width(box):
     """Return the preferred (minimum) width for an ``InlineReplacedBox``."""
-    # TODO: get the actual device size. Or do we really care?
-    # TODO: what about percentage widths?
-    resolve_percentages(box, containing_block=(0, 0))
-    replaced_box_width(box, device_size=None)
-    return box.width
+    if isinstance(box, (int, float)):
+        width = box.style.width
+    else:
+        # TODO: handle the images with no intinsic width
+        _, width, _ = box.replacement
+
+    variable_ratio, fixed_width = variable_and_fixed_widths(box, width)
+    if variable_ratio < 1:
+        return fixed_width / (1 - variable_ratio)
+    else:
+        return 0