Add GetImageSize to PngDataHelper

StabilityMatrix.Avalonia/Helpers/PngDataHelper.cs

@@ -3,6 +3,7 @@ using System.IO;
 using System.Linq;
 using System.Text;
 using System.Text.Json;
+using Avalonia;
 using Force.Crc32;
 using StabilityMatrix.Avalonia.Models;
 using StabilityMatrix.Core.Models;
@@ -84,6 +85,32 @@ public static class PngDataHelper
         return finalImage.ToArray();
     }
 
+    public static Size GetImageSize(byte[] inputImage)
+    {
+        var imageWidthBytes = inputImage[0x10..0x14];
+        var imageHeightBytes = inputImage[0x14..0x18];
+        var imageWidth = BitConverter.ToInt32(imageWidthBytes.Reverse().ToArray());
+        var imageHeight = BitConverter.ToInt32(imageHeightBytes.Reverse().ToArray());
+
+        return new Size(imageWidth, imageHeight);
+    }
+
+    public static Size GetImageSize(BinaryReader reader)
+    {
+        var oldPosition = reader.BaseStream.Position;
+
+        reader.BaseStream.Position = 0x10;
+        var imageWidthBytes = reader.ReadBytes(4);
+        var imageHeightBytes = reader.ReadBytes(4);
+
+        var imageWidth = BitConverter.ToInt32(imageWidthBytes.Reverse().ToArray());
+        var imageHeight = BitConverter.ToInt32(imageHeightBytes.Reverse().ToArray());
+
+        reader.BaseStream.Position = oldPosition;
+
+        return new Size(imageWidth, imageHeight);
+    }
+
     private static byte[] BuildTextChunk(string key, string value)
     {
         var textData = $"{key}\0{value}";