From 345232d30a6dad95c821e269a400c466e3bbd362 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kornel=20Lesi=C5=84ski?= <kornel@geekhood.net>
Date: Tue, 13 Nov 2018 20:44:47 +0000
Subject: [PATCH] Update reductions flag when alpha changed

---
 src/lib.rs     | 4 +++-
 src/png/mod.rs | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 6a9d43f6..f4b49097 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -768,7 +768,9 @@ fn perform_reductions(png: &mut PngData, opts: &Options, deadline: &Deadline) ->
         return reduction_occurred;
     }
 
-    png.try_alpha_reduction(&opts.alphas);
+    if png.try_alpha_reduction(&opts.alphas) {
+        reduction_occurred = true;
+    }
 
     reduction_occurred
 }
diff --git a/src/png/mod.rs b/src/png/mod.rs
index 50665e42..c4597350 100644
--- a/src/png/mod.rs
+++ b/src/png/mod.rs
@@ -587,7 +587,7 @@ impl PngData {
         changed
     }
 
-    pub fn try_alpha_reduction(&mut self, alphas: &HashSet<AlphaOptim>) {
+    pub fn try_alpha_reduction(&mut self, alphas: &HashSet<AlphaOptim>) -> bool {
         assert!(!alphas.is_empty());
         let alphas = alphas.iter().collect::<Vec<_>>();
         let best_size = AtomicMin::new(None);
@@ -623,7 +623,9 @@ impl PngData {
 
         if let Some(best) = best {
             self.raw_data = best.1.raw_data;
+            return true;
         }
+        false
     }
 
     pub fn reduce_alpha_channel(&mut self, optim: AlphaOptim) -> bool {