svg_hexaflexagon_editor: draw also the backfaces

[flexagon-toolkit.git] / src / svg_hexaflexagon_editor.py

diff --git a/src/svg_hexaflexagon_editor.py b/src/svg_hexaflexagon_editor.py
index 48c8646..d64468b 100755 (executable)
--- a/src/svg_hexaflexagon_editor.py
+++ b/src/svg_hexaflexagon_editor.py
@@ -32,6 +32,7 @@ class SvgwriteHexaflexagonDiagram(HexaflexagonDiagram):
         # create some layers and groups
         layers = {
             "Hexagons": svg.layer(label="Hexagons"),
+            "Backfaces": svg.layer(label="Backfaces"),
             "Hexaflexagon": svg.layer(label="Hexaflexagon"),
             "Folding guide": svg.layer(label="Folding guide"),
             "Template": svg.layer(label="Template")
@@ -110,6 +111,24 @@ class SvgwriteHexaflexagonDiagram(HexaflexagonDiagram):
                 ref['clip-path'] = "url(%s)" % (triangle_href + '-clip-path')
                 group.add(ref)
 
+        # draw the backfaces
+        group = self.groups["Backfaces"]
+        for hexagon in self.hexaflexagon.hexagons:
+            for triangle in hexagon.triangles:
+                m = self.get_triangle_backfaces_transform(triangle)
+                svg_matrix = "matrix(%f, %f, %f, %f, %f, %f)" % (m[0], m[3],
+                                                                 m[1], m[4],
+                                                                 m[2], m[5])
+
+                triangle_href = "#hexagon%d-triangle%d" % (hexagon.index, triangle.index)
+
+                # Reuse the content to draw the backface
+                content_href = "#hexagon%d-content" % hexagon.index
+                ref = self.backend.svg.use(content_href)
+                ref['transform'] = svg_matrix
+                ref['clip-path'] = "url(%s)" % (triangle_href + '-clip-path')
+                group.add(ref)
+
     def draw_triangle_template(self, triangle, cx, cy, theta):
         old_active_group = self.backend.active_group
         group_name = "hexagon%d-triangle%d" % (triangle.hexagon.index, triangle.index)