Handle small-caps synthesis

Fix #123.

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 = []
@@ -141,8 +140,10 @@ 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.
@@ -150,12 +151,12 @@ def draw_first_line(stream, textbox, text_overflow, block_ellipsis, matrix):
         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

@@ -38,6 +38,15 @@ PANGO_WRAP_MODE = {
     'WRAP_CHAR': pango.PANGO_WRAP_CHAR,
     'WRAP_WORD_CHAR': pango.PANGO_WRAP_WORD_CHAR
 }
+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

weasyprint/text/ffi.py

@@ -145,6 +145,16 @@ ffi.cdef('''
         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 @@ ffi.cdef('''
         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 ..logger import LOGGER
 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)
 
@@ -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