From c09e8f6d12a43df43456c2bd53f3df882ef07c66 Mon Sep 17 00:00:00 2001
From: Felix Hanau <felix@cloudflare.com>
Date: Thu, 27 Jun 2019 15:05:35 +0100
Subject: [PATCH] Make filter, zlib level and strategy deterministic (#179)

---
 src/lib.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 70ff06ca..f4179808 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -446,7 +446,7 @@ pub fn optimize_from_memory(data: &[u8], opts: &Options) -> PngResult<Vec<u8>> {
     }
 }
 
-#[derive(Debug, PartialEq, Clone, Copy)]
+#[derive(Debug, PartialEq, PartialOrd, Clone, Copy)]
 /// Defines options to be used for a single compression trial
 struct TrialOptions {
     pub filter: u8,
@@ -636,7 +636,7 @@ fn optimize_png(
             }
         });
         let best: Option<TrialWithData> =
-            best.reduce_with(|i, j| if i.1.len() <= j.1.len() { i } else { j });
+            best.reduce_with(|i, j| if i.1.len() < j.1.len() || (i.1.len() == j.1.len() && i.0 < j.0) { i } else { j });
 
         if let Some(better) = best {
             png.idat_data = better.1;