use only relevant icon sizes when saving files

Author: snjo

IcoMerge/Form1.cs

@@ -53,7 +53,7 @@ private void buttonUnpackICO_Click(object sender, EventArgs e)
             foreach (string file in imageFiles)
             {
                 string filePrefix = Path.GetFileNameWithoutExtension(file);
-                IconToBitmaps.LoadFiles(file, folderBrowserDialog1.SelectedPath, filePrefix, "png", radioButton2.Checked);//saveFileDialog1.FileName);
+                IconToBitmaps.Convert(file, folderBrowserDialog1.SelectedPath, filePrefix, "png", radioButton2.Checked);//saveFileDialog1.FileName);
             }
         }
 

IcoMerge/IconToBitmaps.cs

@@ -1,6 +1,8 @@
 using System.Diagnostics;
 using System.Drawing;
 using System.Runtime.InteropServices;
+using System.Security.Cryptography;
+using System.Security.Policy;
 
 
 namespace IcoMerge;
@@ -9,22 +11,13 @@ namespace IcoMerge;
 //https://gist.github.com/Willy-Kimura/d3d3541dee057c583f39005b25df65c8
 class IconToBitmaps
 {
-    public static void UnpackPngIcon(FileStream inputStream, string outputFolder, string filePrefix, string fileExtension)
+    public static List<IconProperties> ReadIconDirectory(int[] bytes, int numberOfIcons)
     {
+        List<IconProperties> iconProperties = new List<IconProperties>();
 
-        long readLength = inputStream.Length;
-        int[] bytes = new int[readLength];
-
-        for (int i = 0; i < readLength; i++)
-        {
-            int b = inputStream.ReadByte();
-            bytes[i] = b;
-        }
-        int numImages = bytes[4];
-        Debug.WriteLine("Icons in file " +  numImages);
-
-        for (int i = 0;i < numImages;i++)
+        for (int i = 0;i < numberOfIcons; i++)
         {
+            IconProperties icon = new IconProperties();
             //get icon attributes
             int listingStart = 6 + (i * 16);
             int width = bytes[listingStart + 0];
@@ -33,6 +26,8 @@ public static void UnpackPngIcon(FileStream inputStream, string outputFolder, st
             int height = bytes[listingStart + 1];
             if (height == 0) { height = 256; }
 
+            //imageSize = Math.Max(width, height);
+
             int size = bytes[listingStart+8];
             size += bytes[listingStart + 9]* 256;
             size += bytes[listingStart + 10] * 256 * 256;
@@ -41,65 +36,128 @@ public static void UnpackPngIcon(FileStream inputStream, string outputFolder, st
             offset += bytes[listingStart + 13] * 256;
             offset += bytes[listingStart + 14] * 256 * 256;
             offset += bytes[listingStart + 15] * 256 * 256 * 256;
-            Debug.WriteLine($"Icon, {width}x{height}, size: {size}b, starting at byte {offset}");
+            Debug.WriteLine($"Icon, {width}x{height}, size: {size}b, starting at byte {offset}");     
+            icon.index = i;
+            icon.offset = offset;
+            icon.size = size;
+            icon.width = width;
+            icon.height = height;
+            iconProperties.Add( icon );
+        }
+        return iconProperties;
+    }
 
-            //Save files
-            string fileName = $"{filePrefix}-{i}-{width}.{fileExtension}";
-            string filePath = Path.Combine(outputFolder, fileName);
-            using (FileStream output_stream = new FileStream(filePath, System.IO.FileMode.OpenOrCreate))
+    public static (int[] bytes, int numberOfIcons) ReadIconToBytes(FileStream inputStream)
+    {
+        long readLength = inputStream.Length;
+        int[] bytes = new int[readLength];
+
+        for (int i = 0; i < readLength; i++)
+        {
+            int b = inputStream.ReadByte();
+            bytes[i] = b;
+        }
+        int numberOfIcons = bytes[4];
+
+        Debug.WriteLine("Icons in file " + numberOfIcons);
+
+        return (bytes, numberOfIcons);
+    }
+
+    public static void SaveFileFromBytes(int[] bytes, int imageSize, int index, int offset, int fileSize, string outputFolder, string filePrefix, string fileExtension)
+    {
+        //Save files
+        string fileName = $"{filePrefix}-{index}-{imageSize}.{fileExtension}";
+        string filePath = Path.Combine(outputFolder, fileName);
+        using (FileStream output_stream = new FileStream(filePath, System.IO.FileMode.OpenOrCreate))
+        {
+            Debug.WriteLine($"Saving PNG-packed icon to PNG: {filePath}, size: {imageSize} from {offset} to {offset + fileSize} out of {bytes.Length} b");
+            using (BinaryWriter bitmap_writer = new BinaryWriter(output_stream))
             {
-                Debug.WriteLine($"Saving PNG-packed icon to PNG: {filePath}, size: {size} from {offset} to {offset+size} out of {bytes.Length} b");
-                using (BinaryWriter bitmap_writer = new BinaryWriter(output_stream))
+                for (int j = 0; j < fileSize; j++)
                 {
-                    for (int j = 0; j < size; j++)
-                    {
-                        bitmap_writer.Write((byte)bytes[offset+j]);
-                    }
-                    bitmap_writer.Flush();
+                    bitmap_writer.Write((byte)bytes[offset + j]);
                 }
-                output_stream.Close();
+                bitmap_writer.Flush();
             }
-            
+            output_stream.Close();
         }
     }
 
 
 
-    public static void LoadFiles(string input_icon, string outputFolder, string filePrefix, string fileExtension, bool UnpackAsPNG)
+    public static void Convert(string input_icon, string outputFolder, string filePrefix, string fileExtension, bool UnpackAsPNG)
     {
+        FileStream input_stream = new FileStream(input_icon, System.IO.FileMode.Open);
+        (int[] bytes, int num) = ReadIconToBytes(input_stream);
+        List<IconProperties> iconList = ReadIconDirectory(bytes, num);// output_stream);
         if (UnpackAsPNG)
         {
-            FileStream input_stream = new FileStream(input_icon, System.IO.FileMode.Open);
-            UnpackPngIcon(input_stream, outputFolder, filePrefix, fileExtension);// output_stream);
+            Debug.WriteLine("Save using PNG packed icon");
+            foreach (IconProperties icon in iconList)
+            {
+                SaveFileFromBytes(bytes, icon.width, icon.index, icon.offset, icon.size, outputFolder, filePrefix, fileExtension);
+            }
             input_stream.Close();
         }
         else
         {
-            UnpackIcoIcon(input_icon, outputFolder, filePrefix, fileExtension);
+            input_stream.Close();
+            Debug.WriteLine("Save using ICO packed icon");
+            List<int> sizes = new List<int>();
+            foreach(IconProperties icon in iconList)
+            {
+                sizes.Add(icon.width);
+            }
+            UnpackIcoIcon(input_icon, sizes, outputFolder, filePrefix, fileExtension);
         }
-        
     }
 
-    public static void UnpackIcoIcon(string sourceFile, string outputFolder, string filePrefix, string fileExtension)
+    public static void UnpackIcoIcon(string sourceFile, List<int> sizes, string outputFolder, string filePrefix, string fileExtension)
     {
-        int[] sizes = { 16, 32, 24, 48, 64, 256 };
+        Debug.Write($"Saving ICO-packed icon {sourceFile} to PNG with sizes: ");
+        foreach (int size in sizes)
+        {
+            Debug.Write($"{size} ");
+        }
+        Debug.WriteLine("");
+
         try
         {
-            for (int j = 0; j < sizes.Length; j++)
-            {
-                Icon? icon = Icon.ExtractIcon(sourceFile, 0, sizes[j]);
-                if (icon != null)
+            //for (int i = 0; i < sizes.Count; i++)
+            //{
+                for (int j = 0; j < sizes.Count; j++)
                 {
-                    string fileName = $"{filePrefix}-{j}-{sizes[j]}.{fileExtension}";
-                    string filePath = Path.Combine(outputFolder, fileName);
-                    Debug.WriteLine($"Saving ICO-packed icon to PNG {filePath}: {icon.Width}x{icon.Height}");
-                    icon.ToBitmap().Save(filePath);
+                    Icon? icon = Icon.ExtractIcon(sourceFile, 0, sizes[j]);
+                    //Icon icon = Icon.ExtractAssociatedIcon(sourceFile);
+                    Debug.WriteLine($"Icon {sourceFile}, size {sizes[j]}, null: {icon == null}");
+
+                    if (icon != null)
+                    {
+                        string fileName = $"{filePrefix}-{j}-{sizes[j]}.{fileExtension}";
+                        string filePath = Path.Combine(outputFolder, fileName);
+                        Debug.WriteLine($"Saving ICO-packed icon to PNG {filePath}: {icon.Width}x{icon.Height}");
+                        icon.ToBitmap().Save(filePath);
+                    }
+                    else
+                    {
+                        Debug.WriteLine("Icon is null");
+                    }
                 }
-            } 
+            //}
         }
         catch (Exception ex)
         {
             Debug.WriteLine(ex.Message);
         }
     }
+
+    public class IconProperties
+    {
+        public int index;
+        public int width;
+        public int height;
+        public int offset;
+        public int size;
+    }
 }