PR: Add font properties handling

.github/workflows/ci.yml

@@ -30,6 +30,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v1
+    - name: Copy Ahem font
+      run: |
+        mkdir -p ~/.local/share/fonts/
+        cp tests/fonts/ahem.ttf ~/.local/share/fonts/ahem.ttf
     - name: Set up Python 3.7
       uses: actions/setup-python@v1
       with:
@@ -52,6 +56,10 @@ jobs:
         python-version: [3.5, 3.6]
     steps:
     - uses: actions/checkout@v1
+    - name: Copy Ahem font
+      run: |
+        mkdir -p ~/.local/share/fonts/
+        cp tests/fonts/ahem.ttf ~/.local/share/fonts/ahem.ttf
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v1
       with:

colosseum/constants.py

@@ -1,5 +1,5 @@
-from .validators import (is_color, is_integer, is_length, is_number,
-                         is_percentage, ValidationError)
+from .exceptions import ValidationError
+from .validators import is_color, is_font_family, is_integer, is_length, is_number, is_percentage
 
 
 class Choices:
@@ -36,13 +36,13 @@ def validate(self, value):
     def __str__(self):
         choices = set([str(c).lower().replace('_', '-') for c in self.constants])
         for validator in self.validators:
-            choices.add(validator.description)
+            choices.update(validator.description.split(', '))
 
         if self.explicit_defaulting_constants:
             for item in self.explicit_defaulting_constants:
                 choices.add(item)
 
-        return ", ".join(sorted(choices))
+        return ", ".join(sorted(set(choices)))
 
 
 ######################################################################
@@ -235,6 +235,8 @@ def __str__(self):
 # 10.8 Leading and half-leading
 ######################################################################
 # line_height
+LINE_HEIGHT_CHOICES = Choices(NORMAL, validators=[is_number, is_length, is_percentage],
+                              explicit_defaulting_constants=[INHERIT])
 # vertical_align
 
 ######################################################################
@@ -317,26 +319,124 @@ def __str__(self):
 ######################################################################
 # font_family
 
+SERIF = 'serif'
+SANS_SERIF = 'sans-serif'
+CURSIVE = 'cursive'
+FANTASY = 'fantasy'
+MONOSPACE = 'monospace'
+
+GENERIC_FAMILY_FONTS = [SERIF, SANS_SERIF, CURSIVE, FANTASY, MONOSPACE]
+
+FONT_FAMILY_CHOICES = Choices(
+    validators=[is_font_family],
+    explicit_defaulting_constants=[INHERIT, INITIAL],
+)
+
 ######################################################################
 # 15.4 Font Styling
 ######################################################################
 # font_style
+NORMAL = 'normal'
+ITALIC = 'italic'
+OBLIQUE = 'oblique'
+
+FONT_STYLE_CHOICES = Choices(
+    NORMAL,
+    ITALIC,
+    OBLIQUE,
+    explicit_defaulting_constants=[INHERIT],
+)
 
 ######################################################################
 # 15.5 Small-caps
 ######################################################################
 # font_variant
+SMALL_CAPS = 'small-caps'
+FONT_VARIANT_CHOICES = Choices(
+    NORMAL,
+    SMALL_CAPS,
+    explicit_defaulting_constants=[INHERIT],
+)
 
 ######################################################################
 # 15.6 Font boldness
 ######################################################################
 # font_weight
+BOLD = 'bold'
+BOLDER = 'bolder'
+LIGHTER = 'lighter'
+
+FONT_WEIGHT_CHOICES = Choices(
+    NORMAL,
+    BOLD,
+    BOLDER,
+    LIGHTER,
+    100,
+    200,
+    300,
+    400,
+    500,
+    600,
+    700,
+    800,
+    900,
+    explicit_defaulting_constants=[INHERIT],
+)
 
 ######################################################################
 # 15.7 Font size
 ######################################################################
 # font_size
 
+# <absolute-size>
+XX_SMALL = 'xx-small'
+X_SMALL = 'x-small'
+SMALL = 'small'
+MEDIUM = 'medium'
+LARGE = 'large'
+X_LARGE = 'x-large'
+XX_LARGE = 'xx-large'
+
+# <relative-size>
+LARGER = 'larger'
+SMALLER = 'smaller'
+
+FONT_SIZE_CHOICES = Choices(
+    XX_SMALL,
+    X_SMALL,
+    SMALL,
+    MEDIUM,
+    LARGE,
+    X_LARGE,
+    XX_LARGE,
+    LARGER,
+    SMALLER,
+    validators=[is_length, is_percentage],
+    explicit_defaulting_constants=[INHERIT],
+)
+
+######################################################################
+# 15.8 Font shorthand
+######################################################################
+
+ICON = 'icon'
+CAPTION = 'caption'
+MENU = 'menu'
+MESSAGE_BOX = 'message-box'
+SMALL_CAPTION = 'small-caption'
+STATUS_BAR = 'status-bar'
+
+SYSTEM_FONT_KEYWORDS = [ICON, CAPTION, MENU, MESSAGE_BOX, SMALL_CAPTION, STATUS_BAR]
+
+INITIAL_FONT_VALUES = {
+    'font_style': NORMAL,
+    'font_variant': NORMAL,
+    'font_weight': NORMAL,
+    'font_size': MEDIUM,
+    'line_height': NORMAL,
+    'font_family': [INITIAL],  # TODO: Depends on user agent. What to use?
+}
+
 ######################################################################
 # 16. Text ###########################################################
 ######################################################################

colosseum/declaration.py

@@ -5,29 +5,89 @@
     BORDER_WIDTH_CHOICES, BOX_OFFSET_CHOICES, CLEAR_CHOICES, COLOR_CHOICES,
     DIRECTION_CHOICES, DISPLAY_CHOICES, FLEX_BASIS_CHOICES,
     FLEX_DIRECTION_CHOICES, FLEX_GROW_CHOICES, FLEX_SHRINK_CHOICES, FLEX_START,
-    FLEX_WRAP_CHOICES, FLOAT_CHOICES, GRID_AUTO_CHOICES,
-    GRID_AUTO_FLOW_CHOICES, GRID_GAP_CHOICES, GRID_PLACEMENT_CHOICES,
-    GRID_TEMPLATE_AREA_CHOICES, GRID_TEMPLATE_CHOICES, INLINE,
-    JUSTIFY_CONTENT_CHOICES, LTR, MARGIN_CHOICES, MAX_SIZE_CHOICES,
+    FLEX_WRAP_CHOICES, FLOAT_CHOICES, FONT_FAMILY_CHOICES, FONT_SIZE_CHOICES,
+    FONT_STYLE_CHOICES, FONT_VARIANT_CHOICES, FONT_WEIGHT_CHOICES,
+    GRID_AUTO_CHOICES, GRID_AUTO_FLOW_CHOICES, GRID_GAP_CHOICES,
+    GRID_PLACEMENT_CHOICES, GRID_TEMPLATE_AREA_CHOICES, GRID_TEMPLATE_CHOICES,
+    INITIAL, INITIAL_FONT_VALUES, INLINE, JUSTIFY_CONTENT_CHOICES,
+    LINE_HEIGHT_CHOICES, LTR, MARGIN_CHOICES, MAX_SIZE_CHOICES, MEDIUM,
     MIN_SIZE_CHOICES, NORMAL, NOWRAP, ORDER_CHOICES, PADDING_CHOICES,
-    POSITION_CHOICES, ROW, SIZE_CHOICES, STATIC, STRETCH,
-    TRANSPARENT, UNICODE_BIDI_CHOICES, VISIBILITY_CHOICES, VISIBLE,
-    Z_INDEX_CHOICES, default,
+    POSITION_CHOICES, ROW, SIZE_CHOICES, STATIC, STRETCH, TRANSPARENT,
+    UNICODE_BIDI_CHOICES, VISIBILITY_CHOICES, VISIBLE, Z_INDEX_CHOICES,
+    default,
 )
+from .exceptions import ValidationError
+from .parser import construct_font, parse_font
 
 _CSS_PROPERTIES = set()
 
 
-def unvalidated_property(name, choices, initial):
-    "Define a simple CSS property attribute."
-    initial = choices.validate(initial)
+def validated_font_property(name, initial):
+    """Define the shorthand CSS font property."""
+    assert isinstance(initial, dict)
+    initial = initial.copy()
 
     def getter(self):
-        return getattr(self, '_%s' % name, initial)
+        font = initial.copy()
+        for property_name in font:
+            font[property_name] = getattr(self, property_name)
+        return font
 
     def setter(self, value):
-        if value != getattr(self, '_%s' % name, initial):
-            setattr(self, '_%s' % name, value)
+        try:
+            font = parse_font(value)
+        except ValidationError:
+            raise ValueError("Invalid value '%s' for CSS property '%s'!" % (value, name))
+
+        for property_name, property_value in font.items():
+            setattr(self, property_name, property_value)
+            self.dirty = True
+        setattr(self, '_%s' % name, value)
+
+    def deleter(self):
+        try:
+            delattr(self, '_%s' % name)
+            self.dirty = True
+        except AttributeError:
+            # Attribute doesn't exist
+            pass
+
+        for property_name in INITIAL_FONT_VALUES:
+            try:
+                delattr(self, property_name)
+                self.dirty = True
+            except AttributeError:
+                # Attribute doesn't exist
+                pass
+
+    _CSS_PROPERTIES.add(name)
+    return property(getter, setter, deleter)
+
+
+def validated_list_property(name, choices, initial, separator=','):
+    """Define a property holding a list values."""
+    if not isinstance(initial, list):
+        raise ValueError('Initial value must be a list!')
+
+    def getter(self):
+        return getattr(self, '_%s' % name, initial).copy()
+
+    def setter(self, value):
+        if not isinstance(value, str):
+            value = separator.join(value)
+        try:
+            # This should be a list of values
+            values = choices.validate(value)
+        except ValueError:
+            raise ValueError("Invalid value '%s' for CSS property '%s'; Valid values are: %s" % (
+                value, name, choices
+            ))
+
+        if not isinstance(values, list):
+            values.split(separator)
+
+        if values != getattr(self, '_%s' % name, initial):
+            setattr(self, '_%s' % name, values[:])
             self.dirty = True
 
     def deleter(self):
@@ -127,6 +187,30 @@ def deleter(self):
     return property(getter, setter, deleter)
 
 
+def unvalidated_property(name, choices, initial):
+    "Define a simple CSS property attribute."
+    initial = choices.validate(initial)
+
+    def getter(self):
+        return getattr(self, '_%s' % name, initial)
+
+    def setter(self, value):
+        if value != getattr(self, '_%s' % name, initial):
+            setattr(self, '_%s' % name, value)
+            self.dirty = True
+
+    def deleter(self):
+        try:
+            delattr(self, '_%s' % name)
+            self.dirty = True
+        except AttributeError:
+            # Attribute doesn't exist
+            pass
+
+    _CSS_PROPERTIES.add(name)
+    return property(getter, setter, deleter)
+
+
 class CSS:
     def __init__(self, **style):
         self._node = None
@@ -222,7 +306,7 @@ def __init__(self, **style):
     max_height = validated_property('max_height', choices=MAX_SIZE_CHOICES, initial=None)
 
     # 10.8 Leading and half-leading
-    # line_height
+    line_height = validated_property('line_height', choices=LINE_HEIGHT_CHOICES, initial=NORMAL)
     # vertical_align
 
     # 11. Visual effects #################################################
@@ -276,22 +360,22 @@ def __init__(self, **style):
 
     # 15. Fonts ##########################################################
     # 15.3 Font family
-    # font_family
+    font_family = validated_list_property('font_family', choices=FONT_FAMILY_CHOICES, initial=[INITIAL])
 
     # 15.4 Font Styling
-    # font_style
+    font_style = validated_property('font_style', choices=FONT_STYLE_CHOICES, initial=NORMAL)
 
     # 15.5 Small-caps
-    # font_variant
+    font_variant = validated_property('font_variant', choices=FONT_VARIANT_CHOICES, initial=NORMAL)
 
     # 15.6 Font boldness
-    # font_weight
+    font_weight = validated_property('font_weight', choices=FONT_WEIGHT_CHOICES, initial=NORMAL)
 
     # 15.7 Font size
-    # font_size
+    font_size = validated_property('font_size', choices=FONT_SIZE_CHOICES, initial=MEDIUM)
 
     # 15.8 Shorthand font property
-    # font
+    font = validated_font_property('font', initial=INITIAL_FONT_VALUES)
 
     # 16. Text ###########################################################
     # 16.1 Indentation
@@ -504,13 +588,16 @@ def keys(self):
     def __str__(self):
         non_default = []
         for name in _CSS_PROPERTIES:
-            try:
-                non_default.append((
-                    name.replace('_', '-'),
-                    getattr(self, '_%s' % name)
-                ))
-            except AttributeError:
-                pass
+            if name == 'font':
+                non_default.append((name, construct_font(getattr(self, name))))
+            else:
+                try:
+                    non_default.append((
+                        name.replace('_', '-'),
+                        getattr(self, '_%s' % name)
+                    ))
+                except AttributeError:
+                    pass
 
         return "; ".join(
             "%s: %s" % (name, value)

colosseum/exceptions.py

@@ -0,0 +1,3 @@
+
+class ValidationError(Exception):
+    pass