Calculate font BBox using simple metrics

Calculating the "real" values is longer, it’s broken for un-optimized fonts,
and seems to be ignored by many PDF readers.

Author: liZe

weasyprint/draw.py

@@ -1157,19 +1157,6 @@ def draw_first_line(stream, textbox, text_overflow, block_ellipsis, x, y,
             if glyph not in font.widths:
                 pango.pango_font_get_glyph_extents(
                     pango_font, glyph, stream.ink_rect, stream.logical_rect)
-                x1, y1, x2, y2 = (
-                    stream.ink_rect.x,
-                    -stream.ink_rect.y - stream.ink_rect.height,
-                    stream.ink_rect.x + stream.ink_rect.width,
-                    -stream.ink_rect.y)
-                if x1 < font.bbox[0]:
-                    font.bbox[0] = int(units_to_double(x1 * 1000) / font_size)
-                if y1 < font.bbox[1]:
-                    font.bbox[1] = int(units_to_double(y1 * 1000) / font_size)
-                if x2 > font.bbox[2]:
-                    font.bbox[2] = int(units_to_double(x2 * 1000) / font_size)
-                if y2 > font.bbox[3]:
-                    font.bbox[3] = int(units_to_double(y2 * 1000) / font_size)
                 font.widths[glyph] = int(round(
                     units_to_double(stream.logical_rect.width * 1000) /
                     font_size))

weasyprint/pdf/fonts.py

@@ -55,6 +55,9 @@ def build_fonts_dictionary(pdf, fonts, optimize_size):
                 width = font.ttfont.getGlyphSet()[key].width
                 font_widths[glyph] = width * ratio
 
+        max_x = max(font_widths.values()) if font_widths else 0
+        bbox = (0, font.descent, max_x, font.ascent)
+
         widths = pydyf.Array()
         for i in sorted(font_widths):
             if i - 1 not in font_widths:
@@ -107,11 +110,11 @@ def build_fonts_dictionary(pdf, fonts, optimize_size):
                 'FontName': font.name,
                 'FontFamily': pydyf.String(font.family),
                 'Flags': font.flags,
-                'FontBBox': pydyf.Array(font.bbox),
+                'FontBBox': pydyf.Array(bbox),
                 'ItalicAngle': font.italic_angle,
                 'Ascent': font.ascent,
                 'Descent': font.descent,
-                'CapHeight': font.bbox[3],
+                'CapHeight': bbox[3],
                 'StemV': font.stemv,
                 'StemH': font.stemh,
                 font_file: font_references_by_file_hash[font.hash],

weasyprint/pdf/stream.py

@@ -84,7 +84,6 @@ def __init__(self, pango_font):
         self.svg = harfbuzz.hb_ot_color_has_svg(hb_face)
         self.stemv = 80
         self.stemh = 80
-        self.bbox = [0, 0, 0, 0]
         self.widths = {}
         self.cmap = {}
         self.used_in_forms = False