Merge pull request #191 from replaysMike/bugs/mbrown/issue175-text-gets-chopped-when-rotated

fixes #175 - Text gets chopped when rotated >60 degrees.

Author: JimBobSquarePants

src/ImageSharp.Drawing/Processing/Processors/Text/DrawTextProcessor{TPixel}.cs

@@ -35,6 +35,7 @@ protected override void BeforeImageApply()
             this.textRenderer = new CachingGlyphRenderer(
                 this.Configuration.MemoryAllocator,
                 this.definition.Text.Length,
+                this.definition.TextOptions,
                 this.definition.Pen,
                 this.definition.Brush != null,
                 this.definition.DrawingOptions.Transform)
@@ -173,22 +174,21 @@ private class CachingGlyphRenderer : IColorGlyphRenderer, IDisposable
             private readonly bool renderFill;
             private bool rasterizationRequired;
 
-            public CachingGlyphRenderer(MemoryAllocator memoryAllocator, int size, IPen pen, bool renderFill, Matrix3x2 transform)
+            public CachingGlyphRenderer(MemoryAllocator memoryAllocator, int size, TextOptions textOptions, IPen pen, bool renderFill, Matrix3x2 transform)
             {
                 this.MemoryAllocator = memoryAllocator;
                 this.currentRenderPosition = default;
                 this.Pen = pen;
                 this.renderFill = renderFill;
                 this.renderOutline = pen != null;
-                this.offset = 2;
+                this.offset = (int)textOptions.Font.Size;
                 if (this.renderFill)
                 {
                     this.FillOperations = new List<DrawingOperation>(size);
                 }
 
                 if (this.renderOutline)
                 {
-                    this.offset = (int)MathF.Ceiling((pen.StrokeWidth * 2) + 2);
                     this.OutlineOperations = new List<DrawingOperation>(size);
                 }
 

tests/ImageSharp.Drawing.Tests/Drawing/Text/DrawTextOnImageTests.cs

@@ -439,6 +439,60 @@ public void CanDrawTextWithEmptyPath()
                 Vector2.Zero));
         }
 
+        [Theory]
+        [WithSolidFilledImages(300, 200, nameof(Color.White), PixelTypes.Rgba32, TestFonts.OpenSans, 32, 75F)]
+        [WithSolidFilledImages(300, 200, nameof(Color.White), PixelTypes.Rgba32, TestFonts.OpenSans, 40, 90F)]
+        public void CanRotateFilledFont_Issue175<TPixel>(
+            TestImageProvider<TPixel> provider,
+            string fontName,
+            int fontSize,
+            float angle)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            Font font = CreateFont(fontName, fontSize);
+            const string text = "QuickTYZ";
+            AffineTransformBuilder builder = new AffineTransformBuilder().AppendRotationDegrees(angle);
+
+            TextOptions textOptions = new(font);
+            FontRectangle bounds = TextMeasurer.Measure(text, textOptions);
+            Matrix3x2 transform = builder.BuildMatrix(Rectangle.Round(new RectangleF(bounds.X, bounds.Y, bounds.Width, bounds.Height)));
+
+            provider.RunValidatingProcessorTest(
+                x => x.SetDrawingTransform(transform).DrawText(textOptions, text, Color.Black),
+                $"F({fontName})-S({fontSize})-A({angle})-{ToTestOutputDisplayText(text)})",
+                TextDrawingComparer,
+                appendPixelTypeToFileName: false,
+                appendSourceFileOrDescription: true);
+        }
+
+        [Theory]
+        [WithSolidFilledImages(300, 200, nameof(Color.White), PixelTypes.Rgba32, TestFonts.OpenSans, 32, 75F, 1)]
+        [WithSolidFilledImages(300, 200, nameof(Color.White), PixelTypes.Rgba32, TestFonts.OpenSans, 40, 90F, 2)]
+        public void CanRotateOutlineFont_Issue175<TPixel>(
+            TestImageProvider<TPixel> provider,
+            string fontName,
+            int fontSize,
+            float angle,
+            int strokeWidth)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            Font font = CreateFont(fontName, fontSize);
+            const string text = "QuickTYZ";
+            AffineTransformBuilder builder = new AffineTransformBuilder().AppendRotationDegrees(angle);
+
+            TextOptions textOptions = new(font);
+            FontRectangle bounds = TextMeasurer.Measure(text, textOptions);
+            Matrix3x2 transform = builder.BuildMatrix(Rectangle.Round(new RectangleF(bounds.X, bounds.Y, bounds.Width, bounds.Height)));
+
+            provider.RunValidatingProcessorTest(
+                x => x.SetDrawingTransform(transform)
+                .DrawText(textOptions, text, Pens.Solid(Color.Black, strokeWidth)),
+                $"F({fontName})-S({fontSize})-A({angle})-STR({strokeWidth})-{ToTestOutputDisplayText(text)})",
+                TextDrawingComparer,
+                appendPixelTypeToFileName: false,
+                appendSourceFileOrDescription: true);
+        }
+
         private static string Repeat(string str, int times) => string.Concat(Enumerable.Repeat(str, times));
 
         private static string ToTestOutputDisplayText(string text)