Diagram.py: fix and simplify drawing polygon fill and stroke

[experiments/RadialSymmetry.git] / Diagram.py

diff --git a/Diagram.py b/Diagram.py
index 8d958f9..28cb064 100755 (executable)
--- a/Diagram.py
+++ b/Diagram.py
@@ -23,7 +23,7 @@ from math import *
 
 class Diagram(object):
 
-    def __init__(self, width, height, background=[1, 1, 1]):
+    def __init__(self, width, height, background=[1, 1, 1], font_size=20):
         self.width = width
         self.height = height
         self.background = background
@@ -38,7 +38,7 @@ class Diagram(object):
 
         cr.select_font_face("Georgia", cairo.FONT_SLANT_NORMAL,
                             cairo.FONT_WEIGHT_NORMAL)
-        cr.set_font_size(20)
+        cr.set_font_size(font_size)
 
         # Adjust the font matrix to left-bottom origin
         M = cr.get_font_matrix()
@@ -97,39 +97,36 @@ class Diagram(object):
         else:
             return None
 
-    def draw_polygon(self, verts, stroke_color=[0, 0, 0], fill_color=None):
+    def _draw_polygon(self, verts):
         cr = self.cr
 
-        if fill_color:
-            v = verts[0]
-            cr.move_to(v[0], v[1])
-            for v in verts[1:]:
-                cr.line_to(v[0], v[1])
-                cr.close_path()
+        v = verts[0]
+        cr.move_to(v[0], v[1])
+        for v in verts[1:]:
+            cr.line_to(v[0], v[1])
+        cr.close_path()
+
+    def draw_polygon(self, verts, fill_color=None, stroke_color=[0, 0, 0]):
+        cr = self.cr
 
+        if fill_color:
+            self._draw_polygon(verts)
             r, g, b, a = self.color_to_rgba(fill_color)
             cr.set_source_rgba(r, g, b, a)
             cr.fill()
 
-        n = len(verts)
-        for i in range(0, n):
-            v1 = verts[i]
-            v2 = verts[(i + 1) % n]
-            cr.move_to(v1[0], v1[1])
-            cr.line_to(v2[0], v2[1])
-
-        r, g, b, a = self.color_to_rgba(stroke_color)
-        cr.set_source_rgba(r, g, b, a)
-        cr.stroke()
+        if stroke_color:
+            self._draw_polygon(verts)
+            r, g, b, a = self.color_to_rgba(stroke_color)
+            cr.set_source_rgba(r, g, b, a)
+            cr.stroke()
 
     def draw_star(self, cx, cy, verts, stroke_color=[0, 0, 0]):
         cr = self.cr
 
-        v = verts[0]
-        cr.move_to(cx, cy)
         for v in verts:
-            cr.line_to(v[0], v[1])
             cr.move_to(cx, cy)
+            cr.line_to(v[0], v[1])
 
         r, g, b, a = self.color_to_rgba(stroke_color)
         cr.set_source_rgba(r, g, b, a)
@@ -161,37 +158,25 @@ class Diagram(object):
                               stroke=False, stroke_color=[0, 0, 0, 0.5]):
         cr = self.cr
 
+        # the position of the center of a rectangle at (0,0)
         mx = width / 2.0
         my = height / 2.0
 
+        # calculate the position of the bottom-left corner after rotating the
+        # rectangle around the center
         rx = cx - (mx * cos(theta) - my * sin(theta))
         ry = cy - (mx * sin(theta) + my * cos(theta))
 
-        cr.save()
-        cr.translate(rx, ry)
-        cr.rotate(theta)
+        self.draw_rect(rx, ry, width, height, theta, fill, fill_color, stroke,
+                       stroke_color)
 
-        if fill:
-            cr.rectangle(0, 0, width, height)
-            r, g, b, a = self.color_to_rgba(fill_color)
-            cr.set_source_rgba(r, g, b, a)
-            cr.fill()
-
-        if stroke:
-            cr.rectangle(0, 0, width, height)
-            r, g, b, a = self.color_to_rgba(stroke_color)
-            cr.set_source_rgba(r, g, b, a)
-            cr.stroke()
-            self.draw_dot(0, 0, 3.0, stroke_color)
-
-        cr.restore()
-
-    def draw_rect(self, x, y, width, height, fill=True, fill_color=[1, 1, 1, 0.8],
+    def draw_rect(self, x, y, width, height, theta=0, fill=True, fill_color=[1, 1, 1, 0.8],
                   stroke=False, stroke_color=[0, 0, 0, 0.5]):
         cr = self.cr
 
         cr.save()
         cr.translate(x, y)
+        cr.rotate(theta)
 
         if fill:
             cr.rectangle(0, 0, width, height)
@@ -244,7 +229,7 @@ class Diagram(object):
         cr.rotate(theta)
 
         if bb_fill or bb_stroke:
-            self.draw_rect(bb[0], bb[1], bb[2], bb[3], bb_fill, bb_fill_color, bb_stroke, bb_stroke_color)
+            self.draw_rect(bb[0], bb[1], bb[2], bb[3], 0, bb_fill, bb_fill_color, bb_stroke, bb_stroke_color)
 
         r, g, b, a = self.color_to_rgba(color)
         cr.set_source_rgba(r, g, b, a)
@@ -294,4 +279,10 @@ if __name__ == "__main__":
 
     diagram.draw_line(0, y, 400, y, [0, 0, 1, 0.2])
 
+    diagram.draw_rect(40, 40, 300, 100, stroke=True)
+    diagram.draw_rect(40, 40, 300, 100, pi / 30, stroke=True)
+
+    diagram.draw_rect(40, 250, 300, 100, stroke=True)
+    diagram.draw_rect_from_center(40 + 150, 250 + 50, 300, 100, theta=pi / 40, stroke=True, stroke_color=[1, 0, 0], fill=False)
+
     diagram.show()