FF-273 - added auto crop image node

fixed issue with mp4 image based subtitles

ImageNodes/ImageNodes.en.json

@@ -1,6 +1,19 @@
 {
   "Flow": {
     "Parts": {
+      "AutoCropImage": {
+        "Outputs": {
+          "1": "Image cropped, saved to new temporary file",
+          "2": "Image was not cropped"
+        },
+        "Description": "Automatically crops an image",
+        "Fields": {
+          "Format": "Format",
+          "Format-Help": "The image format to convert to",
+          "Threshold": "Threshold",
+          "Threshold-Help": "Threshold for entropic density, default is 50.  Must be between 0 and 100."
+        }
+      },
       "ImageFlip": {
         "Outputs": {
           "1": "Image flipped, saved to new temporary file"

ImageNodes/Images/AutoCropImage.cs

@@ -0,0 +1,42 @@
+using SixLabors.ImageSharp.Formats;
+using SixLabors.ImageSharp.Processing;
+using System.ComponentModel;
+
+namespace FileFlows.ImageNodes.Images;
+
+public class AutoCropImage : ImageNode
+{
+    public override int Inputs => 1;
+    public override int Outputs => 2;
+    public override FlowElementType Type => FlowElementType.Process;
+    public override string HelpUrl => "https://docs.fileflows.com/plugins/image-nodes/auto-crop-image";
+    public override string Icon => "fas fa-crop";
+
+    [Slider(1)]
+    [Range(1, 100)]
+    [DefaultValue(50)]
+    public int Threshold { get; set; }
+
+
+    public override int Execute(NodeParameters args)
+    {
+        using var image = Image.Load(args.WorkingFile, out IImageFormat format);
+        int originalWidth = image.Width;
+        int originalHeight= image.Height;
+        float threshold = Threshold / 100f;
+        if (threshold < 0)
+            threshold = 0.5f;
+
+        args.Logger?.ILog("Attempting to auto crop using threshold: " + threshold);
+        image.Mutate(c => c.EntropyCrop(threshold));
+
+        if (image.Width == originalWidth && image.Height == originalHeight)
+            return 2;
+
+        var formatOpts = GetFormat(args);
+        SaveImage(args, image, formatOpts.file, formatOpts.format ?? format);
+        args.Logger?.ILog($"Image cropped from '{originalWidth}x{originalHeight}' to '{image.Width}x{image.Height}'");
+
+        return 1;
+    }
+}

ImageNodes/Tests/ImageTests.cs

@@ -12,6 +12,7 @@ public class ImageNodesTests
     string TestImage1;
     string TestImage2;
     string TempDir;
+    string TestCropImage1, TestCropImage2, TestCropImage3, TestCropImageNoCrop;
 
     public ImageNodesTests()
     {
@@ -21,6 +22,10 @@ public class ImageNodesTests
             TestImage1 = @"D:\videos\pictures\image1.jpg";
             TestImage2 = @"D:\videos\pictures\image2.png";
             TempDir = @"D:\videos\temp";
+            TestCropImage1 = @"D:\images\testimages\crop01.jpg";
+            TestCropImage2 = @"D:\images\testimages\crop02.jpg";
+            TestCropImage3 = @"D:\images\testimages\crop03.jpg";
+            TestCropImageNoCrop = @"D:\images\testimages\nocrop.jpg";
         }
         else
         {
@@ -109,6 +114,72 @@ public class ImageNodesTests
         node.Angle = 270;
         Assert.AreEqual(1, node.Execute(args));
     }
+
+
+    [TestMethod]
+    public void ImageNodes_Basic_AutoCrop_01()
+    {
+        var logger = new TestLogger();
+        var args = new NodeParameters(TestCropImage1, logger, false, string.Empty)
+        {
+            TempPath = TempDir
+        };
+
+        var node = new AutoCropImage();
+        int result = node.Execute(args);
+        
+        string log = logger.ToString();
+        Assert.AreEqual(1, result);
+    }
+
+    [TestMethod]
+    public void ImageNodes_Basic_AutoCrop_02()
+    {
+        var logger = new TestLogger();
+        var args = new NodeParameters(TestCropImage2, logger, false, string.Empty)
+        {
+            TempPath = TempDir
+        };
+
+        var node = new AutoCropImage();
+        node.Threshold = 95;
+        int result = node.Execute(args);
+
+        string log = logger.ToString();
+        Assert.AreEqual(1, result);
+    }
+
+    [TestMethod]
+    public void ImageNodes_Basic_AutoCrop_03()
+    {
+        var logger = new TestLogger();
+        var args = new NodeParameters(TestCropImage3, logger, false, string.Empty)
+        {
+            TempPath = TempDir
+        };
+
+        var node = new AutoCropImage();
+        int result = node.Execute(args);
+
+        string log = logger.ToString();
+        Assert.AreEqual(1, result);
+    }
+
+    [TestMethod]
+    public void ImageNodes_Basic_AutoCrop_NoCrop()
+    {
+        var logger = new TestLogger();
+        var args = new NodeParameters(TestCropImageNoCrop, logger, false, string.Empty)
+        {
+            TempPath = TempDir
+        };
+
+        var node = new AutoCropImage();
+        int result = node.Execute(args);
+
+        string log = logger.ToString();
+        Assert.AreEqual(2, result);
+    }
 }
 
 #endif