Handle small-caps synthesis

docs/api_reference.rst

@@ -369,10 +369,6 @@ WeasyPrint does **not** support the ``@font-feature-values`` rule and the
 values of ``font-variant-alternates`` other than ``normal`` and
 ``historical-forms``.
 
-The ``font-variant-caps`` property is supported but needs the small-caps variant of
-the font to be installed. WeasyPrint does **not** simulate missing small-caps
-fonts.
-
 From `CSS Fonts Module Level 4`_ we only support the
 ``font-variation-settings`` property enabling specific font variations.
 

tests/draw/test_text.py

@@ -900,3 +900,140 @@ def test_huge_justification(assert_pixels):
         }
       </style>
       A B''')
+
+
+def test_font_variant_caps_small(assert_pixels):
+    assert_pixels('''
+        ________
+        _BB_BB__
+        _BB_B_B_
+        _B__BB__
+        _B__B___
+        ________
+    ''', '''
+      <style>
+        @page {size: 8px 6px}
+        p {
+          color: blue;
+          font-variant-caps: small-caps;
+          font-family: %s;
+          font-size: 6px;
+          line-height: 1;
+        }
+      </style>
+      <p>Pp</p>
+    ''' % SANS_FONTS)
+
+
+def test_font_variant_caps_all_small(assert_pixels):
+    assert_pixels('''
+        ________
+        BB_BB___
+        B_BB_B__
+        BB_BB___
+        B__B____
+        ________
+    ''', '''
+      <style>
+        @page {size: 8px 6px}
+        p {
+          color: blue;
+          font-variant-caps: all-small-caps;
+          font-family: %s;
+          font-size: 6px;
+          line-height: 1;
+        }
+      </style>
+      <p>Pp</p>
+    ''' % SANS_FONTS)
+
+
+def test_font_variant_caps_petite(assert_pixels):
+    assert_pixels('''
+        ________
+        _BB_BB__
+        _BB_B_B_
+        _B__BB__
+        _B__B___
+        ________
+    ''', '''
+      <style>
+        @page {size: 8px 6px}
+        p {
+          color: blue;
+          font-variant-caps: petite-caps;
+          font-family: %s;
+          font-size: 6px;
+          line-height: 1;
+        }
+      </style>
+      <p>Pp</p>
+    ''' % SANS_FONTS)
+
+
+def test_font_variant_caps_all_petite(assert_pixels):
+    assert_pixels('''
+        ________
+        BB_BB___
+        B_BB_B__
+        BB_BB___
+        B__B____
+        ________
+    ''', '''
+      <style>
+        @page {size: 8px 6px}
+        p {
+          color: blue;
+          font-variant-caps: all-petite-caps;
+          font-family: %s;
+          font-size: 6px;
+          line-height: 1;
+        }
+      </style>
+      <p>Pp</p>
+    ''' % SANS_FONTS)
+
+
+def test_font_variant_caps_unicase(assert_pixels):
+    assert_pixels('''
+        ________
+        BB______
+        B_B_BB__
+        BB__B_B_
+        B___BB__
+        ____B___
+    ''', '''
+      <style>
+        @page {size: 8px 6px}
+        p {
+          color: blue;
+          font-variant-caps: unicase;
+          font-family: %s;
+          font-size: 6px;
+          line-height: 1;
+        }
+      </style>
+      <p>Pp</p>
+    ''' % SANS_FONTS)
+
+
+def test_font_variant_caps_titling(assert_pixels):
+    assert_pixels('''
+        _BB_____
+        _BB_____
+        _BB__BB_
+        _B___B_B
+        _____BB_
+        _____B__
+    ''', '''
+      <style>
+        @page {size: 8px 6px}
+        p {
+          color: blue;
+          font-family: %s;
+          font-size: 6px;
+          line-height: 1;
+        }
+      </style>
+      <p>Pp</p>
+    ''' % SANS_FONTS)

weasyprint/css/validation/expanders.py

@@ -16,8 +16,8 @@
     background_size, block_ellipsis, border_image_source, border_image_slice,
     border_image_width, border_image_outset, border_image_repeat, border_style,
     border_width, box, column_count, column_width, flex_basis, flex_direction,
-    flex_grow_shrink, flex_wrap, font_family, font_size, font_stretch,
-    font_style, font_weight, gap, grid_line, grid_template, line_height,
+    flex_grow_shrink, flex_wrap, font_family, font_size, font_stretch, font_style,
+    font_variant_caps, font_weight, gap, grid_line, grid_template, line_height,
     list_style_image, list_style_position, list_style_type, mask_border_mode,
     other_colors, overflow_wrap, validate_non_shorthand)
 
@@ -675,7 +675,7 @@ def expand_font(tokens, name):
 
         if font_style([token]) is not None:
             suffix = '-style'
-        elif get_keyword(token) in ('normal', 'small-caps'):
+        elif font_variant_caps([token]) in ('normal', 'small-caps'):
             suffix = '-variant-caps'
         elif font_weight([token]) is not None:
             suffix = '-weight'

weasyprint/css/validation/properties.py

@@ -888,7 +888,7 @@ def font_feature_settings_list(tokens):
 @single_keyword
 def font_variant_alternates(keyword):
     # TODO: support other values
-    # See https://www.w3.org/TR/css-fonts-3/#font-variant-caps-prop
+    # See https://drafts.csswg.org/css-fonts/#font-variant-alternates-prop
     return keyword in ('normal', 'historical-forms')
 
 

weasyprint/draw/text.py

@@ -78,8 +78,7 @@ def draw_first_line(stream, textbox, text_overflow, block_ellipsis, matrix):
     if not textbox.text.strip():
         return []
 
-    font_size = textbox.style['font_size']
-    if font_size < 1e-6:  # default float precision used by pydyf
+    if textbox.style['font_size'] < 1e-6:  # default float precision used by pydyf
         return []
 
     pango.pango_layout_set_single_paragraph_mode(textbox.pango_layout.layout, True)
@@ -126,7 +125,7 @@ def draw_first_line(stream, textbox, text_overflow, block_ellipsis, matrix):
     utf8_text = textbox.pango_layout.text.encode()
     previous_utf8_position = 0
     stream.set_text_matrix(*matrix.values)
-    last_font = None
+    last_font = last_font_size = None
     string = ''
     x_advance = 0
     emojis = []
@@ -141,21 +140,23 @@ def draw_first_line(stream, textbox, text_overflow, block_ellipsis, matrix):
         offset = glyph_item.item.offset
         clusters = glyph_string.log_clusters
 
-        # Add font file content.
+        # Add font file content and get font size.
         pango_font = glyph_item.item.analysis.font
+        description = pango.pango_font_describe(pango_font)
+        font_size = pango.pango_font_description_get_size(description) * FROM_UNITS
         font = stream.add_font(pango_font)
 
         # Get positions of the glyphs in the UTF-8 string.
         utf8_positions = [offset + clusters[i] for i in range(1, num_glyphs)]
         utf8_positions.append(offset + glyph_item.item.length)
 
         # Go through the run glyphs.
-        if font != last_font:
+        if (font, font_size) != (last_font, last_font_size):
             if string:
                 stream.show_text(string)
             string = ''
             stream.set_font_size(font.hash, 1 if font.bitmap else font_size)
-            last_font = font
+            last_font, last_font_size = font, font_size
         string += '<'
         for i in range(num_glyphs):
             glyph_info = glyphs[i]

weasyprint/text/constants.py

@@ -39,6 +39,28 @@
     'WRAP_WORD_CHAR': pango.PANGO_WRAP_WORD_CHAR
 }
 
+if pango.pango_version() < 15000:
+    # Some variants have been added in Pango 1.50.
+    PANGO_VARIANT = {
+        'normal': pango.PANGO_VARIANT_NORMAL,
+        'small-caps': pango.PANGO_VARIANT_SMALL_CAPS,
+        'all-small-caps': pango.PANGO_VARIANT_SMALL_CAPS,
+        'petite-caps': pango.PANGO_VARIANT_SMALL_CAPS,
+        'all-petite-caps': pango.PANGO_VARIANT_SMALL_CAPS,
+        'unicase': pango.PANGO_VARIANT_NORMAL,
+        'titling-caps': pango.PANGO_VARIANT_NORMAL,
+    }
+else:
+    PANGO_VARIANT = {
+        'normal': pango.PANGO_VARIANT_NORMAL,
+        'small-caps': pango.PANGO_VARIANT_SMALL_CAPS,
+        'all-small-caps': pango.PANGO_VARIANT_ALL_SMALL_CAPS,
+        'petite-caps': pango.PANGO_VARIANT_PETITE_CAPS,
+        'all-petite-caps': pango.PANGO_VARIANT_ALL_PETITE_CAPS,
+        'unicase': pango.PANGO_VARIANT_UNICASE,
+        'titling-caps': pango.PANGO_VARIANT_TITLE_CAPS,
+    }
+
 # Language system tags
 # From https://docs.microsoft.com/typography/opentype/spec/languagetags
 LST_TO_ISO = {

weasyprint/text/ffi.py

@@ -145,6 +145,16 @@
         PANGO_WRAP_WORD_CHAR
     } PangoWrapMode;
 
+    typedef enum {
+        PANGO_VARIANT_NORMAL,
+        PANGO_VARIANT_SMALL_CAPS,
+        PANGO_VARIANT_ALL_SMALL_CAPS,
+        PANGO_VARIANT_PETITE_CAPS,
+        PANGO_VARIANT_ALL_PETITE_CAPS,
+        PANGO_VARIANT_UNICASE,
+        PANGO_VARIANT_TITLE_CAPS,
+    } PangoVariant;
+
     typedef enum {
         PANGO_TAB_LEFT
     } PangoTabAlign;
@@ -291,6 +301,8 @@
         PangoFontDescription *desc, double size);
     void pango_font_description_set_variations (
         PangoFontDescription* desc, const char* variations);
+    void pango_font_description_set_variant (
+        PangoFontDescription* desc, PangoVariant variant);
 
     PangoStyle pango_font_description_get_style (const PangoFontDescription *desc);
     const char* pango_font_description_get_variations (

weasyprint/text/fonts.py

@@ -14,8 +14,8 @@
 from ..urls import FILESYSTEM_ENCODING, fetch
 
 from .constants import (  # isort:skip
-    CAPS_KEYS, EAST_ASIAN_KEYS, FONTCONFIG_STRETCH, FONTCONFIG_STYLE,
-    FONTCONFIG_WEIGHT, LIGATURE_KEYS, NUMERIC_KEYS, PANGO_STRETCH, PANGO_STYLE)
+    CAPS_KEYS, EAST_ASIAN_KEYS, FONTCONFIG_STRETCH, FONTCONFIG_STYLE, FONTCONFIG_WEIGHT,
+    LIGATURE_KEYS, NUMERIC_KEYS, PANGO_STRETCH, PANGO_STYLE, PANGO_VARIANT)
 from .ffi import (  # isort:skip
     TO_UNITS, ffi, fontconfig, gobject, harfbuzz, pango, pangoft2, unicode_to_char_p)
 
@@ -287,7 +287,7 @@ def font_features(font_kerning='normal', font_variant_ligatures='normal',
 
     if font_variant_alternates != 'normal':
         # TODO: support other values
-        # See https://www.w3.org/TR/css-fonts-3/#font-variant-caps-prop
+        # See https://drafts.csswg.org/css-fonts/#font-variant-alternates-prop
         if font_variant_alternates == 'historical-forms':
             features['hist'] = 1
 
@@ -319,6 +319,8 @@ def get_font_description(style):
     pango.pango_font_description_set_weight(font_description, font_weight)
     font_size = int(style['font_size'] * TO_UNITS)
     pango.pango_font_description_set_absolute_size(font_description, font_size)
+    font_variant = PANGO_VARIANT[style['font_variant_caps']]
+    pango.pango_font_description_set_variant(font_description, font_variant)
     if style['font_variation_settings'] != 'normal':
         string = ','.join(
             f'{key}={value}' for key, value in