WIP: Add background properties

colosseum/constants.py

@@ -1,6 +1,6 @@
 from .validators import (ValidationError, is_border_spacing, is_color,
                          is_cursor, is_integer, is_length, is_number,
-                         is_percentage, is_quote, is_rect)
+                         is_percentage, is_position, is_quote, is_rect, is_uri)
 
 
 class Choices:
@@ -350,9 +350,27 @@ def value(self, context):
 BACKGROUND_COLOR_CHOICES = Choices(default, TRANSPARENT, validators=[is_color])
 
 # background_image
+# TODO: tests fail if INITIAL is not used, but INITIAL does not seem to be a valid value
+BACKGROUND_IMAGE_CHOICES = Choices(None, validators=[is_uri], explicit_defaulting_constants=[INHERIT, INITIAL])
+
 # background_repeat
+REPEAT = 'repeat'
+REPEAT_X = 'repeat-x'
+REPEAT_Y = 'repeat-y'
+NO_REPEAT = 'no-repeat'
+
+BACKGROUND_REPEAT_CHOICES = Choices(REPEAT, REPEAT_X, REPEAT_Y, NO_REPEAT, explicit_defaulting_constants=[INHERIT])
+
 # background_attachment
+SCROLL = 'scroll'
+FIXED = 'fixed'
+
+# TODO: tests fail if INITIAL is not used, but INITIAL does not seem to be a valid value
+BACKGROUND_ATTACHMENT_CHOICES = Choices(SCROLL, FIXED, explicit_defaulting_constants=[INHERIT, INITIAL])
+
 # background_position
+BACKGROUND_POSITION_CHOICES = Choices(validators=[is_position], explicit_defaulting_constants=[INHERIT])
+
 # background
 
 ######################################################################

colosseum/declaration.py

@@ -1,30 +1,34 @@
-from . import engine as css_engine
-from . import parser
+from . import engine as css_engine, parser
 from .constants import (  # noqa
     ALIGN_CONTENT_CHOICES, ALIGN_ITEMS_CHOICES, ALIGN_SELF_CHOICES, AUTO,
-    BACKGROUND_COLOR_CHOICES, BORDER_COLLAPSE_CHOICES, BORDER_COLOR_CHOICES,
+    BACKGROUND_ATTACHMENT_CHOICES, BACKGROUND_COLOR_CHOICES,
+    BACKGROUND_IMAGE_CHOICES, BACKGROUND_POSITION_CHOICES,
+    BACKGROUND_REPEAT_CHOICES, BORDER_COLLAPSE_CHOICES, BORDER_COLOR_CHOICES,
     BORDER_SPACING_CHOICES, BORDER_STYLE_CHOICES, BORDER_WIDTH_CHOICES,
     BOX_OFFSET_CHOICES, CAPTION_SIDE_CHOICES, CLEAR_CHOICES, CLIP_CHOICES,
-    COLOR_CHOICES, DIRECTION_CHOICES, DISPLAY_CHOICES, EMPTY_CELLS_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,
+    COLOR_CHOICES, CURSOR_CHOICES, DIRECTION_CHOICES, DISPLAY_CHOICES,
+    EMPTY_CELLS_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,
     INITIAL, INLINE, INVERT, JUSTIFY_CONTENT_CHOICES, LETTER_SPACING_CHOICES,
     LTR, MARGIN_CHOICES, MAX_SIZE_CHOICES, MEDIUM, MIN_SIZE_CHOICES, NORMAL,
     NOWRAP, ORDER_CHOICES, ORPHANS_CHOICES, OUTLINE_COLOR_CHOICES,
     OUTLINE_STYLE_CHOICES, OUTLINE_WIDTH_CHOICES, OVERFLOW_CHOICES,
     PADDING_CHOICES, PAGE_BREAK_AFTER_CHOICES, PAGE_BREAK_BEFORE_CHOICES,
-    PAGE_BREAK_INSIDE_CHOICES, POSITION_CHOICES, QUOTES_CHOICES, ROW,
-    SEPARATE, SHOW, SIZE_CHOICES, STATIC, STRETCH, TABLE_LAYOUT_CHOICES,
-    TEXT_ALIGN_CHOICES, TEXT_DECORATION_CHOICES, TEXT_INDENT_CHOICES,
-    TEXT_TRANSFORM_CHOICES, TOP, TRANSPARENT, UNICODE_BIDI_CHOICES,
-    VISIBILITY_CHOICES, VISIBLE, WHITE_SPACE_CHOICES, WIDOWS_CHOICES,
-    WORD_SPACING_CHOICES, Z_INDEX_CHOICES, OtherProperty,
-    TextAlignInitialValue, default, CURSOR_CHOICES,
+    PAGE_BREAK_INSIDE_CHOICES, POSITION_CHOICES, QUOTES_CHOICES, REPEAT, ROW,
+    SCROLL, SEPARATE, SHOW, SIZE_CHOICES, STATIC, STRETCH,
+    TABLE_LAYOUT_CHOICES, TEXT_ALIGN_CHOICES, TEXT_DECORATION_CHOICES,
+    TEXT_INDENT_CHOICES, TEXT_TRANSFORM_CHOICES, TOP, TRANSPARENT,
+    UNICODE_BIDI_CHOICES, VISIBILITY_CHOICES, VISIBLE, WHITE_SPACE_CHOICES,
+    WIDOWS_CHOICES, WORD_SPACING_CHOICES, Z_INDEX_CHOICES, OtherProperty,
+    TextAlignInitialValue, default,
 )
 from .exceptions import ValidationError
-from .wrappers import Border, BorderBottom, BorderLeft, BorderRight, BorderTop, Outline
+from .wrappers import (
+    Background, Border, BorderBottom, BorderLeft, BorderRight, BorderTop,
+    Outline,
+)
 
 _CSS_PROPERTIES = set()
 
@@ -112,7 +116,6 @@ def validated_property(name, choices, initial):
             # Check the value attribute is a callable
             if not callable(value_attr):
                 raise ValueError('Initial value "%s" `value` attribute is not callable!' % initial)
-
         except AttributeError:
             raise ValueError('Initial value "%s" does not have a value attribute!' % initial)
 
@@ -350,11 +353,13 @@ def __init__(self, **style):
 
     # 14.2.1 Background properties
     background_color = validated_property('background_color', choices=BACKGROUND_COLOR_CHOICES, initial=default)
-    # background_image
-    # background_repeat
-    # background_attachment
-    # background_position
-    # background
+    background_image = validated_property('background_image', choices=BACKGROUND_IMAGE_CHOICES, initial=None)
+    background_repeat = validated_property('background_repeat', choices=BACKGROUND_REPEAT_CHOICES, initial=REPEAT)
+    background_attachment = validated_property('background_attachment', choices=BACKGROUND_ATTACHMENT_CHOICES,
+                                               initial=SCROLL)
+    background_position = validated_property('background_position', choices=BACKGROUND_POSITION_CHOICES,
+                                             initial=('0%', '0%'))
+    background = validated_shorthand_property('background', parser=parser.background, wrapper=Background)
 
     # 15. Fonts ##########################################################
     # 15.3 Font family

colosseum/parser.py

@@ -5,7 +5,7 @@
 from .exceptions import ValidationError
 from .shapes import Rect
 from .units import Unit, px
-from .wrappers import BorderSpacing, Cursor, Quotes, Uri
+from .wrappers import BorderSpacing, Cursor, Position, Quotes, Uri
 
 
 def units(value):
@@ -445,3 +445,136 @@ def cursor(values):
         raise ValueError('Value {value} is not a valid cursor value'.format(value=value))
 
     return Cursor(validated_values)
+
+
+##############################################################################
+# Background
+##############################################################################
+def position(value):
+    """
+    [[ <percentage> | <length> | left | center | right ][ <percentage> | <length> | top | center | bottom ]? ] |
+    [[ left | center | right ] || [ top | center | bottom ]]
+
+    Reference:
+    -  https://www.w3.org/TR/2011/REC-CSS2-20110607/colors.html#background-properties
+    """
+    from .constants import (  # noqa
+        BOTTOM, CENTER, LEFT, RIGHT, TOP,
+    )
+
+    if value:
+        if isinstance(value, str):
+            values = [val.strip() for val in value.split()]
+        elif isinstance(value, Sequence):
+            values = value
+        else:
+            raise ValueError('Unknown position %s ' % value)
+    else:
+        raise ValueError('Unknown position %s ' % value)
+
+    if len(values) == 1:
+        # If only one value is specified, the second value is assumed to be 'center'.
+        # If at least one value is not a keyword, then the first value represents the horizontal
+        # position and the second represents the vertical position. Negative <percentage> and
+        # <length> values are allowed.
+        try:
+            return Position(horizontal=units(values[0]))
+        except ValueError:
+            if values[0] in [LEFT, RIGHT, CENTER]:
+                return Position(horizontal=values[0])
+
+            if values[0] in [TOP, BOTTOM]:
+                return Position(vertical=values[0])
+
+    elif len(values) == 2:
+        horizontal, vertical = None, None
+
+        # Check first value
+        try:
+            horizontal = units(values[0])
+        except ValueError:
+            if values[0] in [LEFT, CENTER, RIGHT]:
+                horizontal = values[0]
+
+            if values[0] in [TOP, CENTER, BOTTOM]:
+                vertical = values[0]
+
+        # Check second value
+        try:
+            vertical = units(values[1])
+        except ValueError:
+            if values[1] in [LEFT, CENTER, RIGHT]:
+                horizontal = values[1]
+
+            if values[1] in [TOP, CENTER, BOTTOM]:
+                vertical = values[1]
+
+        return Position(horizontal=horizontal, vertical=vertical)
+
+    raise ValueError('Position contains too many parts!')
+
+
+##############################################################################
+# Background shorthand
+##############################################################################
+def _parse_background_property_part(value, background_dict):
+    """Parse background shorthand property part for known properties."""
+    from .constants import (  # noqa
+        BACKGROUND_ATTACHMENT_CHOICES, BACKGROUND_COLOR_CHOICES, BACKGROUND_IMAGE_CHOICES,
+        BACKGROUND_POSITION_CHOICES, BACKGROUND_REPEAT_CHOICES
+    )
+
+    for property_name, choices in {'background_color': BACKGROUND_COLOR_CHOICES,
+                                   'background_image': BACKGROUND_IMAGE_CHOICES,
+                                   'background_repeat': BACKGROUND_REPEAT_CHOICES,
+                                   'background_attachment': BACKGROUND_ATTACHMENT_CHOICES,
+                                   'background_position': BACKGROUND_POSITION_CHOICES}.items():
+        try:
+            value = choices.validate(value)
+        except (ValueError, ValidationError):
+            continue
+
+        if property_name in background_dict:
+            raise ValueError('Invalid duplicated property!')
+
+        background_dict[property_name] = value
+        return background_dict
+
+    raise ValueError('Background value "{value}" not valid!'.format(value=value))
+
+
+def background(value):
+    """
+    Parse background string into a dictionary of background properties.
+
+    The font CSS property is a shorthand for background-color, background-image,
+    background-repeat, background-attachment, and background-position.
+
+    Reference:
+    - https://www.w3.org/TR/2011/REC-CSS2-20110607/colors.html#background-properties
+    """
+    if value:
+        if isinstance(value, str):
+            values = [val.strip() for val in value.split()]
+        elif isinstance(value, Sequence):
+            values = value
+        else:
+            raise ValueError('Unknown background %s ' % value)
+    else:
+        raise ValueError('Unknown background %s ' % value)
+
+    # We iteratively split by the first left hand space found and try to validate if that part
+    # is a valid <background-color> or <background-image> or <background-repeat> or
+    # <background-attachment> or <background-position> (which can come in any order)
+
+    # We us this dictionary to store parsed values and check that values properties are not
+    # duplicated
+    background_dict = {}
+    for idx, part in enumerate(values):
+        if idx > 2:
+            # Outline can have a maximum of 3 parts
+            raise ValueError('Background property shorthand contains too many parts!')
+
+        background_dict = _parse_background_property_part(part, background_dict)
+
+    return background_dict

colosseum/validators.py

@@ -189,3 +189,18 @@ def is_cursor(value):
 is_cursor.description = ('[ [<uri> ,]* [ auto | crosshair | default | pointer | move | e-resize '
                          '| ne-resize | nw-resize | n-resize | se-resize | sw-resize | s-resize '
                          '| w-resize | text | wait | help | progress ] ]')
+
+
+def is_position(value):
+    """Check if given value is of content quotes and return it."""
+    try:
+        value = parser.position(value)
+    except ValueError:
+        raise ValidationError('Value {value} is not a valid position'.format(value=value))
+
+    return value
+
+
+is_position.description = ('[ [ <percentage> | <length> | left | center | right ] '
+                           '[ <percentage> | <length> | top | center | bottom ]? ] | '
+                           '[ [ left | center | right ] || [ top | center | bottom ] ]')

colosseum/wrappers.py

@@ -42,6 +42,51 @@ def vertical(self):
         return self._horizontal if self._vertical is None else self._vertical
 
 
+class Position:
+    """
+    Position wrapper.
+
+    Examples:
+        Position(1px)
+        Position(1px, 2px)
+        Position('center', 2px)
+        Position('center', 'top')
+    """
+
+    def __init__(self, horizontal=None, vertical=None):
+        self._horizontal = horizontal
+        self._vertical = vertical
+
+    def __repr__(self):
+        pass
+        # if self._vertical is None:
+        #     string = 'Position({horizontal})'.format(horizontal=repr(self._horizontal))
+        # else:
+        #     string = 'Position({horizontal}, {vertical})'.format(horizontal=repr(self._horizontal),
+        #                                                          vertical=repr(self._vertical))
+        # return string
+
+    def __str__(self):
+        pass
+        # if self._vertical is not None:
+        #     string = '{horizontal} {vertical}'.format(horizontal=self._horizontal,
+        #                                               vertical=self._vertical)
+        # else:
+        #     string = '{horizontal}'.format(horizontal=self._horizontal)
+
+        # return string
+
+    @property
+    def horizontal(self):
+        """Return the horizontal position."""
+        return 'center' if self._horizontal is None else self._horizontal
+
+    @property
+    def vertical(self):
+        """Return the vertical position."""
+        return 'center' if self._vertical is None else self._vertical
+
+
 class Quotes:
     """
     Content opening and closing quotes wrapper.
@@ -153,6 +198,11 @@ class Border(Shorthand):
     VALID_KEYS = ['border_width', 'border_style', 'border_color']
 
 
+class Background(Shorthand):
+    VALID_KEYS = ['background_color', 'background_image', 'background_repeat', 'background_attachment',
+                  'background_position']
+
+
 class Uri:
     """Wrapper for a url."""