Add TRANSPARENT_BLACK color constant (#1425)

* Add TRANSPARENT_BLACK color constant

* Improve clarity by using named constant for default window background

* Improve clarity by using named color constant for clearing in arcade.gui.Surface

* Improve clarity in arcade.texture.Texture by using named color constant

* Improve clarity in arcade.gui.widgets by using named color constant

* Use named color constant in bloom defender examples

* Update expected dict size in color constant test

Author: pushfoo

arcade/application.py

@@ -17,6 +17,7 @@
 from arcade import get_display_size
 from arcade import set_viewport
 from arcade import set_window
+from arcade.color import TRANSPARENT_BLACK
 from arcade.context import ArcadeContext
 from arcade.arcade_types import Color
 from arcade import SectionManager
@@ -176,7 +177,7 @@ def __init__(
 
         self._ctx: ArcadeContext = ArcadeContext(self, gc_mode=gc_mode, gl_api=gl_api)
         set_viewport(0, self.width, 0, self.height)
-        self._background_color: Color = (0, 0, 0, 0)
+        self._background_color: Color = TRANSPARENT_BLACK
 
         # See if we should center the window
         if center_window:

arcade/color/__init__.py

@@ -923,6 +923,7 @@
 TROLLEY_GREY = (128, 128, 128, 255)
 TROPICAL_RAIN_FOREST = (0, 117, 94, 255)
 TRUE_BLUE = (0, 115, 207, 255)
+TRANSPARENT_BLACK = (0, 0, 0, 0)
 TUFTS_BLUE = (65, 125, 193, 255)
 TULIP = (255, 135, 141, 255)
 TUMBLEWEED = (222, 170, 136, 255)

arcade/examples/bloom_defender.py

@@ -240,7 +240,7 @@ def on_draw(self):
 
         # Draw to the 'bloom' layer
         self.bloom_screen.use()
-        self.bloom_screen.clear((0, 0, 0, 0))
+        self.bloom_screen.clear(arcade.color.TRANSPARENT_BLACK)
 
         arcade.set_viewport(self.view_left,
                             SCREEN_WIDTH + self.view_left,

arcade/experimental/bloom_multilayer_defender.py

@@ -250,7 +250,7 @@ def on_draw(self):
 
         # Draw to the 'slight bloom' layer
         self.slight_bloom_screen.use()
-        self.slight_bloom_screen.clear((0, 0, 0, 0))
+        self.slight_bloom_screen.clear(arcade.color.TRANSPARENT_BLACK)
 
         arcade.set_viewport(self.view_left,
                             SCREEN_WIDTH + self.view_left,
@@ -262,7 +262,7 @@ def on_draw(self):
 
         # # Draw to the 'intense bloom' layer
         self.intense_bloom_screen.use()
-        self.intense_bloom_screen.clear((0, 0, 0, 0))
+        self.intense_bloom_screen.clear(arcade.color.TRANSPARENT_BLACK)
 
         arcade.set_viewport(self.view_left,
                             SCREEN_WIDTH + self.view_left,

arcade/gui/surface.py

@@ -3,6 +3,7 @@
 
 import arcade
 from arcade import Texture
+from arcade.color import TRANSPARENT_BLACK
 from arcade.gl import Framebuffer
 from arcade.gl import geometry
 from arcade.gui.nine_patch import NinePatchTexture
@@ -102,7 +103,7 @@ def width(self) -> int:
     def height(self) -> int:
         return self._size[1]
 
-    def clear(self, color: arcade.Color = (0, 0, 0, 0)):
+    def clear(self, color: arcade.Color = TRANSPARENT_BLACK):
         """Clear the surface"""
         self.fbo.clear(color=color)
 

arcade/gui/widgets/__init__.py

@@ -16,6 +16,7 @@
 
 import arcade
 from arcade import Sprite, get_window, Texture
+from arcade.color import TRANSPARENT_BLACK
 from arcade.gui.events import (
     UIEvent,
     UIMouseMovementEvent,
@@ -829,7 +830,7 @@ def on_update(self, dt):
 
     def do_render(self, surface: Surface):
         self.prepare_render(surface)
-        surface.clear(color=(0, 0, 0, 0))
+        surface.clear(color=TRANSPARENT_BLACK)
         surface.draw_sprite(0, 0, self.width, self.height, self._sprite)
 
 
@@ -887,7 +888,7 @@ def __init__(
         y=0,
         width=100,
         height=100,
-        color=(0, 0, 0, 0),
+        color=TRANSPARENT_BLACK,
         size_hint=None,
         size_hint_min=None,
         size_hint_max=None,

arcade/texture.py

@@ -17,6 +17,7 @@
     calculate_hit_box_points_simple,
     calculate_hit_box_points_detailed,
 )
+from arcade.color import TRANSPARENT_BLACK
 from arcade.resources import resolve_resource_path
 from arcade.cache.hit_box import HitBoxCache
 from arcade.cache.image import WeakImageCache
@@ -206,7 +207,7 @@ def create_empty(cls, name: str, size: Tuple[int, int]) -> "Texture":
         """
         return Texture(
             name,
-            image=PIL.Image.new("RGBA", size, (0, 0, 0, 0)),
+            image=PIL.Image.new("RGBA", size, TRANSPARENT_BLACK),
             hit_box_algorithm=None,
         )
 
@@ -707,7 +708,7 @@ def make_circle_texture(diameter: int, color: Color, name: Optional[str] = None)
         "circle_texture", diameter, color[0], color[1], color[2]
     )
 
-    bg_color = (0, 0, 0, 0)  # fully transparent
+    bg_color = TRANSPARENT_BLACK  # fully transparent
     img = PIL.Image.new("RGBA", (diameter, diameter), bg_color)
     draw = PIL.ImageDraw.Draw(img)
     draw.ellipse((0, 0, diameter - 1, diameter - 1), fill=color)
@@ -745,7 +746,7 @@ def make_soft_circle_texture(
         outer_alpha,
     )  # name must be unique for caching
 
-    bg_color = (0, 0, 0, 0)  # fully transparent
+    bg_color = TRANSPARENT_BLACK
     img = PIL.Image.new("RGBA", (diameter, diameter), bg_color)
     draw = PIL.ImageDraw.Draw(img)
     max_radius = int(diameter // 2)
@@ -789,7 +790,7 @@ def make_soft_square_texture(
         "gradientsquare", size, color, center_alpha, outer_alpha
     )
 
-    bg_color = (0, 0, 0, 0)  # fully transparent
+    bg_color = TRANSPARENT_BLACK
     img = PIL.Image.new("RGBA", (size, size), bg_color)
     draw = PIL.ImageDraw.Draw(img)
     half_size = int(size // 2)

tests/unit/test_color.py

@@ -2,4 +2,4 @@
 def test_colors():
     from arcade import color
     names = color.__dict__.keys()
-    assert 1012 == len(names)
+    assert 1013 == len(names)