return sequence of dirty rectangles for all drawing operations

Every drawing operation is to return a sequence of rectangles that
have been drawn on, for update optimisation.

1 files changed, 32 insertions, 12 deletions

diff --git a/elements_painter.py b/elements_painter.py
index 63e01a6..e32bf33 100644
--- a/elements_painter.py
+++ b/elements_painter.py
@@ -30,10 +30,13 @@ def paint_ball(ball, surface):
     Draws a ball onto the given PyGame surface.
     ball : the ball to draw => Ball instance
     surface : the destination surface => PyGame.Surface
+    (returns sequence of Rect, or an empty sequence)
     """
+    s = []
     if ball.is_visible():
-        pygame.draw.circle(surface, ball.get_bg_color(), ball.get_center(),
-                           int(ball.get_diameter() / 2))
+        r = pygame.draw.circle(surface, ball.get_bg_color(), ball.get_center(),
+                               int(ball.get_diameter() / 2))
+        s.append(r)
         ball_center = ball.get_center()
         txt_width, txt_height = ball.get_txt_font().size(ball.get_operation().
                                                          get_text())
@@ -41,7 +44,9 @@ def paint_ball(ball, surface):
                         int(ball_center[1] - txt_height / 2))
         txt_surface = ball.get_txt_font().render(
             ball.get_operation().get_text(), 1, ball.get_txt_color())
-        surface.blit(txt_surface, txt_position)
+        r = surface.blit(txt_surface, txt_position)
+        s.append(r)
+    return s
 
 
 def paint_time_bar(time_bar, surface):
@@ -49,20 +54,25 @@ def paint_time_bar(time_bar, surface):
     Draws a time bar onto the given PyGame surface.
     time_bar : the time bar => TimeBar
     surface : the destination surface => PyGame.Surface
+    (returns sequence of Rect)
     """
+    s = []
     edge = time_bar.get_edge()
     dead_rect = (edge[0], edge[1],
                  time_bar.get_width(), time_bar.get_height())
-    pygame.draw.rect(surface, time_bar.get_dead_color(), dead_rect)
+    r = pygame.draw.rect(surface, time_bar.get_dead_color(), dead_rect)
+    s.append(r)
     try:
         value = time_bar.get_value()
         max_value = time_bar.get_max_value()
         active_rect = (edge[0], edge[1],
                        int(time_bar.get_width() * value / max_value),
                        time_bar.get_height())
-        pygame.draw.rect(surface, time_bar.get_active_color(), active_rect)
+        r = pygame.draw.rect(surface, time_bar.get_active_color(), active_rect)
     except NameError:
-        pygame.draw.rect(surface, time_bar.get_active_color(), dead_rect)
+        r = pygame.draw.rect(surface, time_bar.get_active_color(), dead_rect)
+    s.append(r)
+    return s
 
 
 def paint_result_bar(result_bar, surface):
@@ -70,20 +80,25 @@ def paint_result_bar(result_bar, surface):
     Draws a result bar onto a given PyGame surface.
     result_bar : the result bar => ResultBar
     surface : the destination surface => PyGame.Surface
+    (returns sequence of Rect)
     """
+    s = []
     edge = result_bar.get_edge()
     rect = (edge[0], edge[1],
             result_bar.get_width(), result_bar.get_height())
-    pygame.draw.rect(surface, result_bar.get_background(), rect)
+    r = pygame.draw.rect(surface, result_bar.get_background(), rect)
+    s.append(r)
     try:
         text = result_bar.get_header() + str(result_bar.get_result())
     except NameError:
         text = result_bar.get_header()
     text_surface = result_bar.get_text_font().render(
         text, 1, result_bar.get_foreground())
-    surface.blit(text_surface,
-                 (edge[0] + result_bar.get_insets(),
-                  edge[1] + result_bar.get_insets()))
+    r = surface.blit(text_surface,
+                     (edge[0] + result_bar.get_insets(),
+                      edge[1] + result_bar.get_insets()))
+    s.append(r)
+    return s
 
 
 def paint_results(game_area, balls_list, surface):
@@ -92,7 +107,9 @@ def paint_results(game_area, balls_list, surface):
     game_area : area of the balls => tuple of 4 integer
     balls_list : list of balls => list of Ball
     surface : the destination surface => PyGame.Surface
+    (returns sequence of Rect)
     """
+    s = []
     font = pygame.font.Font(None, 40)
     #font = PangoFont(family='Helvetica', size=16)
     LINE_HEIGHT = font.size("0123456789")[1]
@@ -100,14 +117,17 @@ def paint_results(game_area, balls_list, surface):
     ball_index = 0
     BLACK = (0, 0, 0)
     for ball in balls_list:
-        pygame.draw.circle(surface, ball.get_bg_color(),
+        r = pygame.draw.circle(surface, ball.get_bg_color(),
                           (game_area[0] + CIRCLES_RADIUS,
                            game_area[
                                1] + ball_index * LINE_HEIGHT + CIRCLES_RADIUS),
                            CIRCLES_RADIUS)
+        s.append(r)
         txt = ball.get_operation().get_text() + " = " + str(ball.get_operation().
                                                             get_result())
         txt_surface = font.render(txt, 1, BLACK)
-        surface.blit(txt_surface,
+        r = surface.blit(txt_surface,
                      (game_area[0] + 40, game_area[1] + ball_index * LINE_HEIGHT))
+        s.append(r)
         ball_index += 1
+    return s