From a537672dd4d8afe707c950b2c09eb04087385d6b Mon Sep 17 00:00:00 2001
From: Phil Howard <github@gadgetoid.com>
Date: Thu, 28 Mar 2024 15:35:05 +0000
Subject: [PATCH] PNGdec: Don't convert greys if mode=COPY.

---
 micropython/modules/pngdec/pngdec.cpp | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/micropython/modules/pngdec/pngdec.cpp b/micropython/modules/pngdec/pngdec.cpp
index 139cacb1..85f0cd2f 100644
--- a/micropython/modules/pngdec/pngdec.cpp
+++ b/micropython/modules/pngdec/pngdec.cpp
@@ -190,20 +190,26 @@ mp_event_handle_nowait();
                 i &= 0xf;
                 if (x & 1) pixel++;
                 // Just copy the colour into the upper and lower nibble
-                i = (i << 4) | i;
+                if(current_mode != MODE_COPY) {
+                    i = (i << 4) | i;
+                }
             } else if (pDraw->iBpp == 2) {  // 2bpp
                 i = *pixel;
                 i >>= 6 - ((x & 0b11) << 1);
                 i &= 0x3;
                 if ((x & 0b11) == 0b11) pixel++;
                 // Evenly spaced 4-colour palette
-                i = (0xFFB86800 >> (i * 8)) & 0xFF;
+                if(current_mode != MODE_COPY) {
+                    i = (0xFFB86800 >> (i * 8)) & 0xFF;
+                }
             } else {  // 1bpp
                 i = *pixel;
                 i >>= 7 - (x & 0b111);
                 i &= 0b1;
                 if ((x & 0b111) == 0b111) pixel++;
-                i = i ? 255 : 0;
+                if(current_mode != MODE_COPY) {
+                    i = i ? 255 : 0;
+                }
             }
             if(x < target->source.x || x >= target->source.x + target->source.w) continue;