Improve SVG text-anchor attribute

Author: liZe

weasyprint/svg/__init__.py

@@ -8,7 +8,8 @@
 from cssselect2 import ElementWrapper
 
 from ..urls import get_url_attribute
-from .bounding_box import bounding_box, is_valid_bounding_box
+from .bounding_box import (
+    bounding_box, extend_bounding_box, is_valid_bounding_box)
 from .css import parse_declarations, parse_stylesheets
 from .defs import (
     apply_filters, clip_path, draw_gradient_or_pattern, paint_mask, use)
@@ -433,6 +434,12 @@ def draw_node(self, node, font_size, fill_stroke=True):
         display = node.get('display') != 'none'
         visible = display and (node.get('visibility') != 'hidden')
 
+        # Handle text anchor
+        text_anchor = node.get('text-anchor')
+        if node.tag == 'text' and text_anchor in ('middle', 'end'):
+            group = self.stream.add_group(0, 0, 0, 0)  # BBox set after drawing
+            original_stream, self.stream = self.stream, group
+
         # Draw node
         if visible and node.tag in TAGS:
             with suppress(PointError):
@@ -442,6 +449,27 @@ def draw_node(self, node, font_size, fill_stroke=True):
         if display and node.tag not in DEF_TYPES:
             for child in node:
                 self.draw_node(child, font_size, fill_stroke)
+                if node.tag in ('text', 'tspan'):
+                    if not is_valid_bounding_box(child.text_bounding_box):
+                        continue
+                    x1, y1 = child.text_bounding_box[:2]
+                    x2 = x1 + child.text_bounding_box[2]
+                    y2 = y1 + child.text_bounding_box[3]
+                    node.text_bounding_box = extend_bounding_box(
+                        node.text_bounding_box, ((x1, y1), (x2, y2)))
+
+        # Handle text anchor
+        if node.tag == 'text' and text_anchor in ('middle', 'end'):
+            group_id = self.stream.id
+            self.stream = original_stream
+            self.stream.push_state()
+            if is_valid_bounding_box(node.text_bounding_box):
+                x, y, width, height = node.text_bounding_box
+                group.extra['BBox'][:] = (x, y, x + width, y + height)
+                x_align = width / 2 if text_anchor == 'middle' else width
+                self.stream.transform(e=-x_align)
+            self.stream.draw_x_object(group_id)
+            self.stream.pop_state()
 
         # Apply mask
         mask = self.masks.get(parse_url(node.get('mask')).fragment)

weasyprint/svg/text.py

@@ -44,8 +44,6 @@ def text(svg, node, font_size):
 
     layout, _, _, width, height, _ = split_first_line(
         node.text, style, svg.context, inf, 0)
-    # TODO: get real values
-    x_bearing, y_bearing = 0, 0
 
     # Get rotations and translations
     x, y, dx, dy, rotate = [], [], [], [], [0]
@@ -89,19 +87,8 @@ def text(svg, node, font_size):
             letter_spacing = (text_length - width) / spaces_count
         width = text_length
 
-    # Align text box horizontally
-    x_align = 0
-    text_anchor = node.get('text-anchor')
     # TODO: use real values
     ascent, descent = font_size * .8, font_size * .2
-    if text_anchor == 'middle':
-        x_align = - (width / 2 + x_bearing)
-        if letter_spacing and node.text:
-            x_align -= (len(node.text) - 1) * letter_spacing / 2
-    elif text_anchor == 'end':
-        x_align = - (width + x_bearing)
-        if letter_spacing and node.text:
-            x_align -= (len(node.text) - 1) * letter_spacing
 
     # Align text box vertically
     # TODO: This is a hack. Other baseline alignment tags are not supported.
@@ -111,11 +98,11 @@ def text(svg, node, font_size):
     alignment_baseline = node.get(
         'dominant-baseline', node.get('alignment-baseline'))
     if display_anchor == 'middle':
-        y_align = -height / 2 - y_bearing
+        y_align = -height / 2
     elif display_anchor == 'top':
-        y_align = -y_bearing
+        pass
     elif display_anchor == 'bottom':
-        y_align = -height - y_bearing
+        y_align = -height
     elif alignment_baseline in ('central', 'middle'):
         # TODO: This is wrong, we use font top-to-bottom
         y_align = (ascent + descent) / 2 - descent
@@ -157,16 +144,14 @@ def text(svg, node, font_size):
         width *= scale_x
         if i:
             x += letter_spacing
+        svg.cursor_position = x + width, y
 
-        x_position = x + svg.cursor_d_position[0] + x_align
+        x_position = x + svg.cursor_d_position[0]
         y_position = y + svg.cursor_d_position[1] + y_align
-        cursor_position = x + width, y
         angle = last_r if r is None else r
         points = (
-            (cursor_position[0] + x_align + svg.cursor_d_position[0],
-             cursor_position[1] + y_align + svg.cursor_d_position[1]),
-            (cursor_position[0] + x_align + width + svg.cursor_d_position[0],
-             cursor_position[1] + y_align + height + svg.cursor_d_position[1]))
+            (x_position, y_position),
+            (x_position + width, y_position - height))
         node.text_bounding_box = extend_bounding_box(
             node.text_bounding_box, points)
 
@@ -179,7 +164,6 @@ def text(svg, node, font_size):
         emojis = draw_first_line(
             svg.stream, TextBox(layout, style), 'none', 'none', matrix)
         emoji_lines.append((font_size, x, y, emojis))
-        svg.cursor_position = cursor_position
 
     svg.stream.end_text()
     svg.stream.pop_state()