From b8bb3293cb07aa30138a10e506e4e95e1bf73c79 Mon Sep 17 00:00:00 2001
From: Peter Tribe <eq2k@hotmail.com>
Date: Thu, 19 Sep 2019 09:30:13 -0700
Subject: [PATCH] Added: ability to skip unneeded chunks for optimization mode

---
 src/ImageSharp/Formats/Png/IPngEncoderOptions.cs |  5 +++++
 src/ImageSharp/Formats/Png/PngEncoderCore.cs     | 13 +++++++++----
 src/ImageSharp/Formats/Png/PngEncoderOptions.cs  |  6 ++++++
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/ImageSharp/Formats/Png/IPngEncoderOptions.cs b/src/ImageSharp/Formats/Png/IPngEncoderOptions.cs
index 87fd2582a..0f416cb7b 100644
--- a/src/ImageSharp/Formats/Png/IPngEncoderOptions.cs
+++ b/src/ImageSharp/Formats/Png/IPngEncoderOptions.cs
@@ -57,5 +57,10 @@ namespace SixLabors.ImageSharp.Formats.Png
         /// Gets a value indicating whether this instance should write an Adam7 interlaced image.
         /// </summary>
         PngInterlaceMode? InterlaceMethod { get; }
+
+        /// <summary>
+        /// Gets a value indicating whether this instance should skip certain chunks to decrease file size
+        /// </summary>
+        bool Optimized { get; }
     }
 }
diff --git a/src/ImageSharp/Formats/Png/PngEncoderCore.cs b/src/ImageSharp/Formats/Png/PngEncoderCore.cs
index 09575bb28..4442bdb0d 100644
--- a/src/ImageSharp/Formats/Png/PngEncoderCore.cs
+++ b/src/ImageSharp/Formats/Png/PngEncoderCore.cs
@@ -155,10 +155,15 @@ namespace SixLabors.ImageSharp.Formats.Png
             this.WriteHeaderChunk(stream);
             this.WritePaletteChunk(stream, quantized);
             this.WriteTransparencyChunk(stream, pngMetadata);
-            this.WritePhysicalChunk(stream, metadata);
-            this.WriteGammaChunk(stream);
-            this.WriteExifChunk(stream, metadata);
-            this.WriteTextChunks(stream, pngMetadata);
+
+            if (!this.options.Optimized)
+            {
+                this.WritePhysicalChunk(stream, metadata);
+                this.WriteGammaChunk(stream);
+                this.WriteExifChunk(stream, metadata);
+                this.WriteTextChunks(stream, pngMetadata);
+            }
+
             this.WriteDataChunks(image.Frames.RootFrame, quantized, stream);
             this.WriteEndChunk(stream);
             stream.Flush();
diff --git a/src/ImageSharp/Formats/Png/PngEncoderOptions.cs b/src/ImageSharp/Formats/Png/PngEncoderOptions.cs
index dd6c66cb7..5d4be8f14 100644
--- a/src/ImageSharp/Formats/Png/PngEncoderOptions.cs
+++ b/src/ImageSharp/Formats/Png/PngEncoderOptions.cs
@@ -29,6 +29,7 @@ namespace SixLabors.ImageSharp.Formats.Png
             this.Quantizer = source.Quantizer;
             this.Threshold = source.Threshold;
             this.InterlaceMethod = source.InterlaceMethod;
+            this.Optimized = source.Optimized;
         }
 
         /// <summary>
@@ -78,5 +79,10 @@ namespace SixLabors.ImageSharp.Formats.Png
         /// Gets or sets a value indicating whether this instance should write an Adam7 interlaced image.
         /// </summary>
         public PngInterlaceMode? InterlaceMethod { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether this instance should skip certain chunks to decrease file size
+        /// </summary>
+        public bool Optimized { get; set; }
     }
 }