From c5ce1a8029dcd92ad6c4df173bff860c2d7fd293 Mon Sep 17 00:00:00 2001
From: Ryan Oldenburg <guzba8@gmail.com>
Date: Sun, 7 Feb 2021 21:15:02 -0600
Subject: [PATCH] bugfix for minifyBy2 power > 1

---
 src/pixie/images.nim         |  14 +++++++++-----
 tests/images/minifiedBy4.png | Bin 0 -> 161 bytes
 tests/test_images.nim        |   6 ++++++
 3 files changed, 15 insertions(+), 5 deletions(-)
 create mode 100644 tests/images/minifiedBy4.png

diff --git a/src/pixie/images.nim b/src/pixie/images.nim
index 5426bb8..95bf711 100644
--- a/src/pixie/images.nim
+++ b/src/pixie/images.nim
@@ -176,15 +176,16 @@ proc minifyBy2*(image: Image, power = 1): Image =
   if power == 0:
     return image.copy()
 
+  var src = image
   for i in 1 .. power:
-    result = newImage(image.width div 2, image.height div 2)
+    result = newImage(src.width div 2, src.height div 2)
     for y in 0 ..< result.height:
       for x in 0 ..< result.width:
         let
-          a = image.getRgbaUnsafe(x * 2 + 0, y * 2 + 0)
-          b = image.getRgbaUnsafe(x * 2 + 1, y * 2 + 0)
-          c = image.getRgbaUnsafe(x * 2 + 1, y * 2 + 1)
-          d = image.getRgbaUnsafe(x * 2 + 0, y * 2 + 1)
+          a = src.getRgbaUnsafe(x * 2 + 0, y * 2 + 0)
+          b = src.getRgbaUnsafe(x * 2 + 1, y * 2 + 0)
+          c = src.getRgbaUnsafe(x * 2 + 1, y * 2 + 1)
+          d = src.getRgbaUnsafe(x * 2 + 0, y * 2 + 1)
 
         let color = rgba(
           ((a.r.uint32 + b.r + c.r + d.r) div 4).uint8,
@@ -195,6 +196,9 @@ proc minifyBy2*(image: Image, power = 1): Image =
 
         result.setRgbaUnsafe(x, y, color)
 
+    # Set src as this result for if we do another power
+    src = result
+
 proc magnifyBy2*(image: Image, power = 1): Image =
   ## Scales image image up by 2 ^ power.
   if power < 0:
diff --git a/tests/images/minifiedBy4.png b/tests/images/minifiedBy4.png
new file mode 100644
index 0000000000000000000000000000000000000000..6e5769b2b757cf262dec690bed767f63c79ed920
GIT binary patch
literal 161
zcmeAS@N?(olHy`uVBq!ia0vp^k|4~%1|*NXY)uAI8J;eVAr*{or)=bHFc4t&|K%#t
zdiKY~Nr5v|PRx7|JK>f7rYUS|cI-&lc;Z*3!f}<!RZ0KvJ&-H#f6TnVTc=8|d*10s
zXJU#jhP9Rip7|QZuc%_ZbA{A)hnAdGr{|Y+x}HzHSR5%c^EI<8PjXU%=++ZJI~hD(
L{an^LB{Ts51%^L;

literal 0
HcmV?d00001

diff --git a/tests/test_images.nim b/tests/test_images.nim
index 105c929..6bf3ff2 100644
--- a/tests/test_images.nim
+++ b/tests/test_images.nim
@@ -85,3 +85,9 @@ block:
     a = readImage("tests/images/flipped1.png")
     b = a.minifyBy2()
   b.writeFile("tests/images/minifiedBy2.png")
+
+block:
+  let
+    a = readImage("tests/images/flipped1.png")
+    b = a.minifyBy2(2)
+  b.writeFile("tests/images/minifiedBy4.png")