From 41b3078da8851d62ab30a584457dbeb69545e98c Mon Sep 17 00:00:00 2001
From: "byte[]" <byteslice@airmail.cc>
Date: Mon, 6 Jul 2020 14:10:35 -0400
Subject: [PATCH] fix apng encoding

---
 lib/philomena/processors/png.ex | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/lib/philomena/processors/png.ex b/lib/philomena/processors/png.ex
index 32d5d240..5a536dca 100644
--- a/lib/philomena/processors/png.ex
+++ b/lib/philomena/processors/png.ex
@@ -3,10 +3,11 @@ defmodule Philomena.Processors.Png do
 
   def process(analysis, file, versions) do
     dimensions = analysis.dimensions
+    animated? = analysis.animated?
 
     {:ok, intensities} = Intensities.file(file)
 
-    scaled = Enum.flat_map(versions, &scale_if_smaller(file, dimensions, &1))
+    scaled = Enum.flat_map(versions, &scale_if_smaller(file, animated?, dimensions, &1))
 
     %{
       intensities: intensities,
@@ -35,13 +36,13 @@ defmodule Philomena.Processors.Png do
     optimized
   end
 
-  defp scale_if_smaller(_file, _dimensions, {:full, _target_dim}) do
+  defp scale_if_smaller(_file, _animated?, _dimensions, {:full, _target_dim}) do
     [{:symlink_original, "full.png"}]
   end
 
-  defp scale_if_smaller(file, {width, height}, {thumb_name, {target_width, target_height}}) do
+  defp scale_if_smaller(file, animated?, {width, height}, {thumb_name, {target_width, target_height}}) do
     if width > target_width or height > target_height do
-      scaled = scale(file, {target_width, target_height})
+      scaled = scale(file, animated?, {target_width, target_height})
 
       [{:copy, scaled, "#{thumb_name}.png"}]
     else
@@ -49,16 +50,22 @@ defmodule Philomena.Processors.Png do
     end
   end
 
-  defp scale(file, {width, height}) do
+  defp scale(file, animated?, {width, height}) do
     scaled = Briefly.create!(extname: ".png")
 
     scale_filter =
       "scale=w=#{width}:h=#{height}:force_original_aspect_ratio=decrease,format=rgb32"
 
     {_output, 0} =
-      System.cmd("ffmpeg", ["-loglevel", "0", "-y", "-i", file, "-vf", scale_filter, scaled])
+      cond do
+        animated? ->
+          System.cmd("ffmpeg", ["-loglevel", "0", "-y", "-i", file, "-plays", "0", "-vf", scale_filter, "-f", "apng", scaled])
 
-    {_output, 0} = System.cmd("optipng", ["-i0", "-o1", "-quiet", "-clobber", scaled])
+        true ->
+          System.cmd("ffmpeg", ["-loglevel", "0", "-y", "-i", file, "-vf", scale_filter, scaled])
+      end
+
+    System.cmd("optipng", ["-i0", "-o1", "-quiet", "-clobber", scaled])
 
     scaled
   end