From 80176f0940ec85a3cb1b4d6b676baf76e68bd282 Mon Sep 17 00:00:00 2001
From: Grant Sanderson <grant@3blue1brown.com>
Date: Thu, 10 May 2018 19:55:06 -0700
Subject: [PATCH] Replaced background_alpha with background_opacity

---
 active_projects/eola2/cramer.py |  2 +-
 camera/camera.py                | 10 +++++-----
 old_projects/WindingNumber_G.py |  2 +-
 old_projects/nn/part1.py        |  6 +++---
 old_projects/pi_day.py          |  6 +++---
 old_projects/wallis.py          |  2 +-
 utils/color.py                  |  3 ++-
 7 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/active_projects/eola2/cramer.py b/active_projects/eola2/cramer.py
index 69eb2d0a..ff858f45 100644
--- a/active_projects/eola2/cramer.py
+++ b/active_projects/eola2/cramer.py
@@ -206,7 +206,7 @@ class LeaveItToComputers(TeacherStudentsScene):
 
 class PrerequisiteKnowledge(TeacherStudentsScene):
     CONFIG = {
-        "camera_config": {"background_alpha": 255}
+        "camera_config": {"background_opacity": 1}
     }
 
     def construct(self):
diff --git a/camera/camera.py b/camera/camera.py
index cd3127cd..4dd1e5ff 100644
--- a/camera/camera.py
+++ b/camera/camera.py
@@ -34,7 +34,7 @@ class Camera(object):
         "frame_shape": (FRAME_HEIGHT, FRAME_WIDTH),
         "space_center": ORIGIN,
         "background_color": BLACK,
-        "background_alpha": 0,  # Out of rgb_max_val
+        "background_opacity": 0,
         # Points in vectorized mobjects with norm greater
         # than this value will be rescaled.
         "max_allowable_norm": FRAME_WIDTH,
@@ -94,7 +94,7 @@ class Camera(object):
             self.background = self.background.astype(self.pixel_array_dtype)
         else:
             background_rgba = color_to_int_rgba(
-                self.background_color, alpha=self.background_alpha
+                self.background_color, self.background_opacity
             )
             self.background = np.zeros(
                 list(self.pixel_shape) + [self.n_rgb_coords],
@@ -115,10 +115,10 @@ class Camera(object):
         retval = np.array(pixel_array)
         if convert_from_floats:
             retval = np.apply_along_axis(
-                lambda f: (
-                    f * self.rgb_max_val).astype(self.pixel_array_dtype),
+                lambda f: (f * self.rgb_max_val).astype(self.pixel_array_dtype),
                 2,
-                retval)
+                retval
+            )
         return retval
 
     def set_pixel_array(self, pixel_array, convert_from_floats=False):
diff --git a/old_projects/WindingNumber_G.py b/old_projects/WindingNumber_G.py
index 4b65bb31..b5880ed3 100644
--- a/old_projects/WindingNumber_G.py
+++ b/old_projects/WindingNumber_G.py
@@ -2884,7 +2884,7 @@ class ZeroFoundOnBoundary(Scene):
 class AllOfTheVideos(Scene):
     CONFIG = {
         "camera_config" : {
-            "background_alpha" : 255,
+            "background_opacity" : 1,
         }
     }
     def construct(self):
diff --git a/old_projects/nn/part1.py b/old_projects/nn/part1.py
index cdd3618d..177b9622 100644
--- a/old_projects/nn/part1.py
+++ b/old_projects/nn/part1.py
@@ -1479,7 +1479,7 @@ class AskAboutLayers(PreviewMNistNetwork):
 
 class BreakUpMacroPatterns(IntroduceEachLayer):
     CONFIG = {
-        "camera_config" : {"background_alpha" : 255},
+        "camera_config" : {"background_opacity" : 1},
         "prefixes" : [
             "nine", "eight", "four",
             "upper_loop", "right_line",
@@ -1868,7 +1868,7 @@ class BreakUpMicroPatterns(BreakUpMacroPatterns):
 class SecondLayerIsLittleEdgeLayer(IntroduceEachLayer):
     CONFIG = {
         "camera_config" : {
-            "background_alpha" : 255,
+            "background_opacity" : 1,
         },
         "network_mob_config" : {
             "layer_to_layer_buff" : 2,
@@ -2081,7 +2081,7 @@ class SecondLayerIsLittleEdgeLayer(IntroduceEachLayer):
 
 class EdgeDetection(Scene):
     CONFIG = {
-        "camera_config" : {"background_alpha" : 255}
+        "camera_config" : {"background_opacity" : 1}
     }
     def construct(self):
         lion = ImageMobject("Lion")
diff --git a/old_projects/pi_day.py b/old_projects/pi_day.py
index bea9b697..c5c3a3bd 100644
--- a/old_projects/pi_day.py
+++ b/old_projects/pi_day.py
@@ -468,7 +468,7 @@ class TauFalls(Scene):
 class EulerWrites628(Scene):
     CONFIG = {
         "camera_config" : {
-            "background_alpha" : 255,
+            "background_opacity" : 1,
         }
     }
     def construct(self):
@@ -548,7 +548,7 @@ class EulerWrites628(Scene):
 class HeroAndVillain(Scene):
     CONFIG = {
         "camera_config" : {
-            "background_alpha" : 255,
+            "background_opacity" : 1,
         } 
     }
     def construct(self):
@@ -987,7 +987,7 @@ class SpecialThanks(Scene):
 class EndScene(PatreonEndScreen):
     CONFIG = {
         "camera_config" : {
-            "background_alpha" : 255,
+            "background_opacity" : 1,
         }
     }
     def construct(self):
diff --git a/old_projects/wallis.py b/old_projects/wallis.py
index 707d7d94..b071e81f 100644
--- a/old_projects/wallis.py
+++ b/old_projects/wallis.py
@@ -4958,7 +4958,7 @@ class KeeperAndSailorForSineProduct(KeeperAndSailor):
 
 class Conclusion(TeacherStudentsScene):
     CONFIG = {
-        "camera_config": {"background_alpha": 255},
+        "camera_config": {"background_opacity": 1},
     }
 
     def construct(self):
diff --git a/utils/color.py b/utils/color.py
index a3df972e..f8999670 100644
--- a/utils/color.py
+++ b/utils/color.py
@@ -39,7 +39,8 @@ def color_to_int_rgb(color):
     return (255 * color_to_rgb(color)).astype('uint8')
 
 
-def color_to_int_rgba(color, alpha=255):
+def color_to_int_rgba(color, opacity=1.0):
+    alpha = int(255 * opacity)
     return np.append(color_to_int_rgb(color), alpha)