Add support for drawtext argument

FFMpegCore.Test/ArgumentBuilderTest.cs

@@ -3,6 +3,7 @@
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using System;
 using System.Collections.Generic;
+using FFMpegCore.FFMPEG;
 
 namespace FFMpegCore.Test
 {
@@ -174,6 +175,37 @@ public void Builder_BuildString_Speed()
             Assert.AreEqual(str, "-i \"input.mp4\" -preset fast \"output.mp4\"");
         }
 
+        [TestMethod]
+        public void Builder_BuildString_DrawtextFilter()
+        {
+
+            var container = new ArgumentContainer
+            {
+                new InputArgument("input.mp4"),
+                new DrawTextArgument("Stack Overflow", "/path/to/font.ttf",
+                    ("fontcolor", "white"),
+                    ("fontsize", "24"),
+                    ("box", "1"),
+                    ("boxcolor", "black@0.5"),
+                    ("boxborderw", "5"),
+                    ("x", "(w-text_w)/2"),
+                    ("y", "(h-text_h)/2")),
+                new OutputArgument("output.mp4")
+            };
+            var result = new FFMpeg().Convert(container);
+
+            var str = GetArgumentsString(new DrawTextArgument("Stack Overflow", "/path/to/font.ttf", 
+                ("fontcolor", "white"),
+                ("fontsize", "24"),
+                ("box", "1"),
+                ("boxcolor", "black@0.5"),
+                ("boxborderw", "5"),
+                ("x", "(w-text_w)/2"),
+                ("y", "(h-text_h)/2")));
+
+            Assert.AreEqual("-i \"input.mp4\" -vf drawtext=\"text='Stack Overflow': fontfile=/path/to/font.ttf: fontcolor=white: fontsize=24: box=1: boxcolor=black@0.5: boxborderw=5: x=(w-text_w)/2: y=(h-text_h)/2\" \"output.mp4\"", str);
+        }
+
         [TestMethod]
         public void Builder_BuildString_StartNumber()
         {

FFMpegCore/FFMPEG/Argument/Atoms/DrawTextArgument.cs

@@ -0,0 +1,31 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace FFMpegCore.FFMPEG.Argument
+{
+    /// <summary>
+    /// Drawtext video filter argument
+    /// </summary>
+    public class DrawTextArgument : Argument<IEnumerable<(string key, string value)>>
+    {
+        public DrawTextArgument(string text, string fontPath, params (string, string)[] optionalArguments) 
+            : base(new[] {("text", text), ("fontfile", fontPath)}.Concat(optionalArguments))
+        {
+        }
+
+        public override string GetStringValue()
+        {
+            return $"-vf drawtext=\"{string.Join(": ", Value.Select(FormatArgumentPair))}\" ";
+        }
+
+        private static string FormatArgumentPair((string key, string value) pair)
+        {
+            return $"{pair.key}={EncloseIfContainsSpace(pair.value)}";
+        }
+
+        private static string EncloseIfContainsSpace(string input)
+        {
+            return input.Contains(" ") ? $"'{input}'" : input;
+        }
+    }
+}

FFMpegCore/FFMpegCore.csproj

@@ -10,9 +10,9 @@
     <Version>1.0.12</Version>
     <AssemblyVersion>1.1.0.0</AssemblyVersion>
     <FileVersion>1.1.0.0</FileVersion>
-    <PackageReleaseNotes>Minor fixes and refactoring</PackageReleaseNotes>
+    <PackageReleaseNotes>Add support for drawtext</PackageReleaseNotes>
     <LangVersion>8</LangVersion>
-    <PackageVersion>1.1.0</PackageVersion>
+    <PackageVersion>1.2.0</PackageVersion>
     <Authors>Vlad Jerca, Malte Rosenbjerg</Authors>
     <PackageTags>ffmpeg ffprobe convert video audio mediafile resize analyze muxing</PackageTags>
     <RepositoryType>GitHub</RepositoryType>