test ArtistFadeOverlay

sappho/particle.py

@@ -54,7 +54,8 @@ class pygame:
 
 
 # Indicate to center artist's image
-CENTER = object()
+def CENTER(image):
+    return tuple(x // 2 for x in image.get_size())
 
 
 class Particle(object):
@@ -557,8 +558,8 @@ def __init__(self, image, origin=CENTER, special_flags=0):
                 additive, subtractive, etc)
         """
         self.image = image
-        if origin is CENTER:
-            self.origin = tuple(x // 2 for x in self.image.get_size())
+        if callable(origin):
+            self.origin = origin(self.image)
         else:
             self.origin = origin
         self.special_flags = special_flags
@@ -602,9 +603,14 @@ def __init__(self, image, origin, tints,
                 additive, subtractive, etc) the tint will be applied to
                 the image. By default this is multiplicative.
         """
-        self.image = image.convert_alpha()
-        if origin is CENTER:
-            self.origin = tuple(x // 2 for x in self.image.get_size())
+        self.image = image
+        try:
+            self.image = self.image.convert_alpha()
+        except:  # pragma: no cover
+            pass
+
+        if callable(origin):
+            self.origin = origin(self.image)
         else:
             self.origin = origin
         self.tints = tints

tests/test_particle.py

@@ -352,7 +352,8 @@ def test_artist_draw_center(self):
             particle.Particle(0, 1, 1, 0, 3, 'pixel'),
             particle.EmitterBurst.single(1),
             artist=particle.ArtistSimple(
-                block, particle.ArtistSimple.CENTER),
+                block, particle.CENTER
+            ),
         )
         world = pygame.surface.Surface((4, 4))
         world.fill((0, 255, 0), pygame.Rect(0, 0, 4, 4))
@@ -368,5 +369,63 @@ def test_artist_draw_center(self):
         assert(compare_surfaces(desired_world, world))
 
 
+class TestArtistFadeOverlay(unittest.TestCase):
+    def test_artist_draw_origin(self):
+        block = pygame.surface.Surface((2, 2))
+        block.fill((255, 0, 0), pygame.Rect(0, 0, 2, 2))
+
+        ps = particle.ParticleSystem(
+            particle.Particle(0, 1, 1, 0, 3, 'pixel'),
+            particle.EmitterBurst.single(1),
+            artist=particle.ArtistFadeOverlay(
+                block, (0, 0),
+                [(255, 255, 255, 255), (255, 255, 255, 255)]
+            ),
+        )
+        world = pygame.surface.Surface((4, 4))
+        world.fill((0, 255, 0), pygame.Rect(0, 0, 4, 4))
+
+        desired_world = pygame.surface.Surface((4, 4))
+        desired_world.fill((0, 255, 0), pygame.Rect(0, 0, 4, 4))
+        for x in (1, 2):
+            for y in (1, 2):
+                # Ugh this is only 254 for some reason
+                # get it together pygame
+                desired_world.set_at((x, y), (254, 0, 0))
+
+        ps.update_state(1)
+        ps.draw_on(world)
+        assert(compare_surfaces(desired_world, world))
+
+    def test_artist_draw_center(self):
+        block = pygame.surface.Surface((2, 2))
+        block.fill((255, 0, 0), pygame.Rect(0, 0, 2, 2))
+
+        ps = particle.ParticleSystem(
+            particle.Particle(0, 1, 1, 0, 3, 'pixel'),
+            particle.EmitterBurst.single(1),
+            artist=particle.ArtistFadeOverlay(
+                block, particle.CENTER,
+                [(255, 255, 255, 255), (255, 255, 255, 255)]
+            ),
+        )
+        world = pygame.surface.Surface((4, 4))
+        world.fill((0, 255, 0), pygame.Rect(0, 0, 4, 4))
+
+        desired_world = pygame.surface.Surface((4, 4))
+        desired_world.fill((0, 255, 0), pygame.Rect(0, 0, 4, 4))
+        for x in (0, 1):
+            for y in (0, 1):
+                # Ugh this is only 254 for some reason
+                # get it together pygame
+                desired_world.set_at((x, y), (254, 0, 0))
+
+        ps.update_state(1)
+        ps.draw_on(world)
+
+        print(world.get_at((1, 1)))
+        assert(compare_surfaces(desired_world, world))
+
+
 if __name__ == '__main__':
     unittest.main()