From 613aa8c579624ba30b243c1baf809485a500bb81 Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Sun, 31 Jul 2016 11:06:47 +0000
Subject: [PATCH] Reimplement 6846010 correctly.

The bug was actually not in ReadPng*, but in WritePng.
---
 src/resource.cpp | 6 +++---
 src/style.cpp    | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/resource.cpp b/src/resource.cpp
index 107047e3..c7551d9a 100644
--- a/src/resource.cpp
+++ b/src/resource.cpp
@@ -149,7 +149,7 @@ static std::shared_ptr<Pixmap> ReadPngIntoPixmap(png_struct *png_ptr, png_info *
     pixmap->data = std::vector<uint8_t>(pixmap->stride * pixmap->height);
     uint8_t **rows = png_get_rows(png_ptr, info_ptr);
     for(size_t y = 0; y < pixmap->height; y++) {
-        uint8_t *srcRow = flip ? rows[y] : rows[pixmap->height - y - 1];
+        uint8_t *srcRow = flip ? rows[pixmap->height - y - 1] : rows[y];
         memcpy(&pixmap->data[pixmap->stride * y], srcRow,
                pixmap->width * pixmap->GetBytesPerPixel());
     }
@@ -229,9 +229,9 @@ bool Pixmap::WritePng(FILE *f, bool flip) {
     std::vector<uint8_t *> rows;
     for(size_t y = 0; y < height; y++) {
         if(flip) {
-            rows.push_back(&data[stride * y]);
-        } else {
             rows.push_back(&data[stride * (height - y - 1)]);
+        } else {
+            rows.push_back(&data[stride * y]);
         }
     }
 
diff --git a/src/style.cpp b/src/style.cpp
index 8e0c9b9f..9d8ffaed 100644
--- a/src/style.cpp
+++ b/src/style.cpp
@@ -371,7 +371,7 @@ void TextWindow::ScreenBackgroundImage(int link, uint32_t v) {
         if(GetOpenFile(&bgImageFile, "", PngFileFilter)) {
             FILE *f = ssfopen(bgImageFile, "rb");
             if(f) {
-                SS.bgImage.pixmap = Pixmap::ReadPng(f, /*flip=*/true);
+                SS.bgImage.pixmap = Pixmap::ReadPng(f);
                 SS.bgImage.scale  = SS.GW.scale;
                 SS.bgImage.origin = SS.GW.offset.ScaledBy(-1);
                 fclose(f);