Modularize tail rendering

nyan/nyancat.py

@@ -0,0 +1,88 @@
+import os.path as path
+import random
+import sys
+import time
+from PIL import Image # Requires the Pillow library
+
+background_color = (0x0f, 0x4d, 0x8f)
+tail_colors = [
+    (0xff, 0x00, 0x00),
+    (0xff, 0x99, 0x00),
+    (0xff, 0xff, 0x00),
+    (0x00, 0xff, 0x00),
+    (0x00, 0x99, 0xff),
+    (0x66, 0x33, 0xff),
+]
+
+anim_cat = []
+for i in range(0, 6):
+    frame = Image.open('%s/cat/%d.png' % (path.dirname(__file__), i))
+    assert (32, 16) == frame.size
+    anim_cat.append(frame)
+anim_sparkle = []
+for i in range(0, 5):
+    frame = Image.open('%s/sparkle/%d.png' % (path.dirname(__file__), i))
+    anim_sparkle.append(frame)
+
+
+class Sparkle(object):
+    def __init__(self, w, h):
+        half_h = anim_sparkle[0].size[1] // 2
+        self.x = random.randint(0, w)
+        self.y = random.randint(half_h, h - half_h)
+        self.frame_index = 0
+
+class Nyancat(object):
+    def __init__(self, width, height):
+        self.width = width
+        self.height = height
+        self.sparkles = []
+
+    def render(self):
+        for anim_frame in anim_cat:
+            if len(self.sparkles) < 32:
+                self.sparkles.append(Sparkle(self.width, self.height))
+
+            frame = bytearray(self.width * self.height * 3)
+            # Render the background
+            for i in range(self.width * self.height):
+                frame[i*3:i*3+3] = background_color
+
+            # Render the tail
+            for (x, tail_y) in enumerate(self.plot_tail(self.width - 10)):
+                for (y, color) in enumerate(tail_colors, tail_y - len(tail_colors) // 2):
+                    if 0 <= y < self.height:
+                        i = y * self.width + x
+                        frame[i*3:i*3+3] = color
+
+            # Copy animated frame
+            for anim_x in range(anim_frame.size[0]):
+                for anim_y in range(anim_frame.size[1]):
+                    pix = anim_frame.getpixel((anim_x, anim_y))
+                    if pix[3] != 0: # Test for alpha
+                        x = (self.width - anim_frame.size[0]) + anim_x
+                        y = (self.height // 2 - anim_frame.size[1] // 2) + anim_y
+                        i = ((y * self.width) + x) * 3
+                        frame[i:i+3] = pix[:3]
+
+            # Render and update the sparkles
+            for sp in self.sparkles:
+                for x in range(anim_sparkle[0].size[0]):
+                    for y in range(anim_sparkle[0].size[1]):
+                        pix_x = sp.x + x - anim_sparkle[0].size[0] // 2
+                        pix_y = sp.y + y - anim_sparkle[0].size[1] // 2
+                        if 0 <= pix_x < self.width and 0 <= pix_y < self.height:
+                            i = pix_y * self.width + pix_x
+                            pix = anim_sparkle[sp.frame_index].getpixel((x, y))
+                            if pix[3] != 0:
+                                frame[i*3:i*3+3] = pix[:3]
+                sp.x -= 3
+                sp.frame_index += 1
+            # Remove expired sparkles
+            self.sparkles = list(filter(lambda sp: sp.frame_index < len(anim_sparkle), self.sparkles))
+
+            sys.stdout.buffer.write(frame)
+            time.sleep(1 / 30)
+
+    def plot_tail(self, width):
+        pass # Virtual