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 +1,9 @@
-from .validators import (is_color, is_integer, is_length, is_number,
-                         is_percentage, ValidationError)
+import os
+import sys
+
+from .validators import (ValidationError, is_color, is_font_family,
+                         is_integer, is_length,
+                         is_number, is_percentage)
 
 
 class Choices:
@@ -34,15 +38,15 @@ def validate(self, value):
         raise ValueError()
 
     def __str__(self):
-        choices = set([str(c).lower().replace('_', '-') for c in self.constants])
+        choices = [str(c).lower().replace('_', '-') for c in self.constants]
         for validator in self.validators:
-            choices.add(validator.description)
+            choices += validator.description.split(', ')
 
         if self.explicit_defaulting_constants:
             for item in self.explicit_defaulting_constants:
-                choices.add(item)
+                choices.append(item)
 
-        return ", ".join(sorted(choices))
+        return ", ".join(sorted(set(choices)))
 
 
 ######################################################################
@@ -235,6 +239,8 @@ 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 +323,174 @@ 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]
+
+
+def available_font_families():
+    """List available font family names."""
+    if sys.platform == 'darwin':
+        return _available_font_families_mac()
+    elif sys.platform.startswith('linux'):
+        return _available_font_families_unix()
+    elif os.name == 'nt':
+        return _available_font_families_win()
+
+    return []
+
+
+def _available_font_families_mac():
+    """List available font family names on mac."""
+    from ctypes import cdll, util
+    from rubicon.objc import ObjCClass
+    appkit = cdll.LoadLibrary(util.find_library('AppKit'))  # noqa
+    NSFontManager = ObjCClass("NSFontManager")
+    NSFontManager.declare_class_property('sharedFontManager')
+    NSFontManager.declare_class_property("sharedFontManager")
+    NSFontManager.declare_property("availableFontFamilies")
+    manager = NSFontManager.sharedFontManager
+    return list(sorted(str(item) for item in manager.availableFontFamilies if item))
+
+
+def _available_font_families_unix():
+    """List available font family names on unix."""
+    import subprocess
+    p = subprocess.check_output(['fc-list', ':', 'family'])
+    fonts = p.decode().split('\n')
+    return list(sorted(set(item for item in fonts if item)))
+
+
+def _available_font_families_win():
+    """List available font family names on windows."""
+    import winreg
+    key = winreg.OpenKey(winreg.HKEY_LOCAL_MACHINE,
+                         r"Software\Microsoft\Windows NT\CurrentVersion\Fonts",
+                         0,
+                         winreg.KEY_READ)
+    fonts = set()
+    for idx in range(0, winreg.QueryInfoKey(key)[1]):
+        font_name = winreg.EnumValue(key, idx)[0]
+        font_name = font_name.replace(' (TrueType)', '')
+        fonts.add(font_name)
+    return list(sorted(fonts))
+
+
+AVAILABLE_FONT_FAMILIES = available_font_families()
+FONT_FAMILY_CHOICES = Choices(
+    validators=[is_font_family(generic_family=GENERIC_FAMILY_FONTS, font_families=AVAILABLE_FONT_FAMILIES)],
+    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

@@ -12,22 +12,80 @@
     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,
+    Z_INDEX_CHOICES, default, FONT_STYLE_CHOICES, FONT_VARIANT_CHOICES,
+    FONT_WEIGHT_CHOICES, FONT_SIZE_CHOICES, MEDIUM, FONT_FAMILY_CHOICES, INITIAL,
+    INITIAL_FONT_VALUES, LINE_HEIGHT_CHOICES,
 )
+from .fonts import construct_font_property, parse_font_property
+
 
 _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
+        for property_name in font:
+            font[property_name] = getattr(self, property_name)
+        return getattr(self, '_%s' % name, construct_font_property(font))
 
     def setter(self, value):
-        if value != getattr(self, '_%s' % name, initial):
-            setattr(self, '_%s' % name, value)
+        font = parse_font_property(value)
+        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):
+        # TODO: A copy is returned so if the user mutates it,
+        # it will not affect the stored value
+        return getattr(self, '_%s' % name, initial)[:]
+
+    def setter(self, value):
+        try:
+            if not isinstance(value, str):
+                value = separator.join(value)
+
+            # This should be a list of values
+            values = choices.validate(value)
+            if not isinstance(values, list):
+                values.split(separator)
+        except ValueError:
+            raise ValueError("Invalid value '%s' for CSS property '%s'; Valid values are: %s" % (
+                value, name, choices
+            ))
+
+        if values != getattr(self, '_%s' % name, initial):
+            setattr(self, '_%s' % name, values[:])
             self.dirty = True
 
     def deleter(self):
@@ -127,6 +185,30 @@ 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 +304,7 @@ 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 +358,22 @@ 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