Changeset 1991Tweet

Timestamp:

Nov 16, 2007, 10:02:59 PM (13 years ago)

Author:

Sam Hocevar

Message:

• New pattern for future 3-dimensional explanations.

Location:

www/study

Files:

• pat5-1-2.png (added)
• study.py (modified) (3 diffs)

www/study/study.py

@@ -499 +499 @@
 test42x(gradient256bw, ERROR_FSTEIN, threshold_4).writePng("grad4-2-3.png")
 
-# Pattern 5.0.1: 8-colour palette
+# Pattern 5.1.1: 8-colour palette
 dest = Image((512, 64))
 for x in range(512):
@@ -513 +513 @@
 lenna256 = Image("lenna256.png")
 
-# Output 5.0.1: RGB dithering
+# Output 5.1.1: 8-colour Floyd-Steinberg RGB dithering
+# Output 5.1.2: 8-colour gamma-corrected Floyd-Steinberg RGB dithering
 def test501(src, mat, func):
     (w, h) = src.size()
@@ -534 +535 @@
 test501(lenna256, ERROR_FSTEIN, test42x).writePng("out5-1-2.png")
 
+# Pattern 5.1.2: red-green or red-yellow pattern?
+dest = Image((240, 160))
+for x in range(80):
+    for y in range(80):
+        r = DITHER_BAYER44[(y / 4) % 4][(x / 4) % 4] > 11
+        g = DITHER_BAYER44[(y / 4) % 4][(x / 4) % 4] > 13
+        dest.setRgb(x, y, r, 0, g)
+    for y in range(80, 160):
+        r = DITHER_BAYER44[y % 4][x % 4] > 11
+        g = DITHER_BAYER44[y % 4][x % 4] > 13
+        dest.setRgb(x, y, r, 0, g)
+for x in range(80, 160):
+    for y in range(80):
+        r = DITHER_BAYER44[(y / 4 + 1) % 4][(x / 4 + 1) % 4] > 11
+        g = DITHER_BAYER44[(y / 4) % 4][(x / 4) % 4] > 13
+        dest.setRgb(x, y, r, 0, g)
+    for y in range(80, 160):
+        r = DITHER_BAYER44[(y + 1) % 4][(x + 1) % 4] > 11
+        g = DITHER_BAYER44[y % 4][x % 4] > 13
+        dest.setRgb(x, y, r, 0, g)
+for x in range(160, 240):
+    for y in range(80):
+        r = DITHER_BAYER44[(y / 4) % 4][(x / 4 + 1) % 4] > 11
+        g = DITHER_BAYER44[(y / 4) % 4][(x / 4) % 4] > 13
+        dest.setRgb(x, y, r, 0, g)
+    for y in range(80, 160):
+        r = DITHER_BAYER44[y % 4][(x + 1) % 4] > 11
+        g = DITHER_BAYER44[y % 4][x % 4] > 13
+        dest.setRgb(x, y, r, 0, g)
+dest.writePng("pat5-1-2.png")
+
 ##############################################################################
 # Place temporary cruft below this