Better layout for both horizontal and vertical.

Author: JimBobSquarePants

samples/DrawShapesWithImageSharp/Program.cs

@@ -52,9 +52,11 @@ private static void OutputStars()
             DrawFatL();
 
             DrawText("Hello World");
+
             DrawText(
                 "Hello World Hello World Hello World Hello World Hello World Hello World Hello World",
-                new EllipsePolygon(PointF.Empty, 100));
+                 new EllipsePolygon(PointF.Empty, 100));
+            // new RectangularPolygon(PointF.Empty, new SizeF(100, 100)));
         }
 
         private static void DrawText(string text)
@@ -69,21 +71,21 @@ private static void DrawText(string text)
 
         private static void DrawText(string text, IPath path)
         {
-            FontFamily fam = SystemFonts.Get("Arial");
-            var font = new Font(fam, 30);
+            FontFamily family = SystemFonts.Get("Arial");
+            Font font = new(family, 30);
             TextOptions textOptions = new(font)
             {
                 WrappingLength = path.ComputeLength(),
                 VerticalAlignment = VerticalAlignment.Top,
                 HorizontalAlignment = HorizontalAlignment.Left,
 
                 // Enable this to test vertical layout mode.
-                LayoutMode = LayoutMode.VerticalLeftRight
+                //LayoutMode = LayoutMode.VerticalLeftRight
             };
 
             IPathCollection glyphs = TextBuilder.GenerateGlyphs(text, path, textOptions);
 
-            glyphs.SaveImage("Text-Path", text + ".png");
+            glyphs.SaveImageWithPath(path, "Text-Path", text + ".png");
         }
 
         private static void DrawFatL()
@@ -223,61 +225,67 @@ private static void OutputClippedRectangle()
 
         public static void SaveImage(this IPath shape, params string[] path) => new PathCollection(shape).SaveImage(path);
 
-        public static void SaveImage(this IPathCollection shape, params string[] path)
+        public static void SaveImage(this IPathCollection collection, params string[] path)
         {
-            shape = shape.Translate(-shape.Bounds.Location) // touch top left
-                    .Translate(new Vector2(10)); // move in from top left
+            // Offset the path collection to ensure our resultant image is
+            // large enough to contain the rendered output.
+            collection = collection.Translate(-collection.Bounds.Location);
+
+            int width = (int)(collection.Bounds.Left + collection.Bounds.Right);
+            int height = (int)(collection.Bounds.Top + collection.Bounds.Bottom);
+            using var img = new Image<Rgba32>(width, height);
+
+            // Fill the canvas background and draw our shape
+            img.Mutate(i => i.Fill(Color.DarkBlue));
 
+            // Draw our path collection.
+            img.Mutate(i => i.Fill(Color.HotPink, collection));
+
+            // Ensure directory exists
             string fullPath = IOPath.GetFullPath(IOPath.Combine("Output", IOPath.Combine(path)));
+            IODirectory.CreateDirectory(IOPath.GetDirectoryName(fullPath));
+            img.Save(fullPath);
+        }
 
-            // pad even amount around shape
-            int width = (int)(shape.Bounds.Left + shape.Bounds.Right);
-            int height = (int)(shape.Bounds.Top + shape.Bounds.Bottom);
+        public static void SaveImageWithPath(this IPathCollection collection, IPath shape, params string[] path)
+        {
+            // Offset the shape and path collection to ensure our resultant image is
+            // large enough to contain the rendered output.
+            shape = shape.Translate(-collection.Bounds.Location);
+            collection = collection.Translate(-collection.Bounds.Location);
 
-            using (var img = new Image<Rgba32>(width, height))
-            {
-                img.Mutate(i => i.Fill(Color.DarkBlue).Draw(Color.HotPink, 3, new EllipsePolygon(width / 2F, height / 2F, 93)));
+            var bounds = RectangleF.Union(shape.Bounds, collection.Bounds);
+            int width = (int)(bounds.Left + bounds.Right);
+            int height = (int)(bounds.Top + bounds.Bottom);
 
-                foreach (IPath s in shape)
-                {
-                    // In ImageSharp.Drawing.Paths there is an extension method that takes in an IShape directly.
-                    img.Mutate(i => i.Fill(Color.HotPink, s));
-                }
+            using var img = new Image<Rgba32>(width, height);
 
-                // img.Draw(Color.LawnGreen, 1, new ShapePath(shape));
+            // Fill the canvas background and draw our shape
+            img.Mutate(i => i.Fill(Color.DarkBlue).Fill(Color.White.WithAlpha(.25F), shape));
 
-                // Ensure directory exists
-                IODirectory.CreateDirectory(IOPath.GetDirectoryName(fullPath));
+            // Draw our path collection.
+            img.Mutate(i => i.Fill(Color.HotPink, collection));
 
-                img.Save(fullPath);
-            }
+            // Ensure directory exists
+            string fullPath = IOPath.GetFullPath(IOPath.Combine("Output", IOPath.Combine(path)));
+            IODirectory.CreateDirectory(IOPath.GetDirectoryName(fullPath));
+            img.Save(fullPath);
         }
 
         public static void SaveImage(this IPath shape, int width, int height, params string[] path)
             => new PathCollection(shape).SaveImage(width, height, path);
 
         public static void SaveImage(this IPathCollection shape, int width, int height, params string[] path)
         {
-            string fullPath = IOPath.GetFullPath(IOPath.Combine("Output", IOPath.Combine(path)));
-
-            using (var img = new Image<Rgba32>(width, height))
-            {
-                img.Mutate(i => i.Fill(Color.DarkBlue));
+            using var img = new Image<Rgba32>(width, height);
+            img.Mutate(i => i.Fill(Color.DarkBlue));
+            img.Mutate(i => i.Fill(Color.HotPink, shape));
 
-                // In ImageSharp.Drawing.Paths there is an extension method that takes in an IShape directly.
-                foreach (IPath s in shape)
-                {
-                    // In ImageSharp.Drawing.Paths there is an extension method that takes in an IShape directly.
-                    img.Mutate(i => i.Fill(Color.HotPink, s));
-                }
-
-                // img.Draw(Color.LawnGreen, 1, new ShapePath(shape));
-
-                // Ensure directory exists
-                IODirectory.CreateDirectory(IOPath.GetDirectoryName(fullPath));
+            // Ensure directory exists
+            string fullPath = IOPath.GetFullPath(IOPath.Combine("Output", IOPath.Combine(path)));
+            IODirectory.CreateDirectory(IOPath.GetDirectoryName(fullPath));
 
-                img.Save(fullPath);
-            }
+            img.Save(fullPath);
         }
     }
 }

src/ImageSharp.Drawing/Shapes/SegmentInfo.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Six Labors.
+// Copyright (c) Six Labors.
 // Licensed under the Apache License, Version 2.0.
 
 namespace SixLabors.ImageSharp.Drawing
@@ -14,7 +14,7 @@ public struct SegmentInfo
         public PointF Point;
 
         /// <summary>
-        /// The angle of the segment.
+        /// The angle of the segment. Measured in radians.
         /// </summary>
         public float Angle;
     }

src/ImageSharp.Drawing/Shapes/Text/BaseGlyphBuilder.cs

@@ -19,17 +19,13 @@ internal class BaseGlyphBuilder : IGlyphRenderer
         // ReSharper disable once InconsistentNaming
         protected readonly PathBuilder builder;
 #pragma warning restore SA1401 // Fields should be private
-        private readonly List<IPath> paths = new List<IPath>();
+        private readonly List<IPath> paths = new();
         private Vector2 currentPoint = default;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="BaseGlyphBuilder"/> class.
         /// </summary>
-        public BaseGlyphBuilder()
-        {
-            // glyphs are renderd realative to bottom left so invert the Y axis to allow it to render on top left origin surface
-            this.builder = new PathBuilder();
-        }
+        public BaseGlyphBuilder() => this.builder = new PathBuilder();
 
         /// <summary>
         /// Gets the paths that have been rendered by this.
@@ -42,10 +38,7 @@ void IGlyphRenderer.EndText()
         }
 
         /// <inheritdoc/>
-        void IGlyphRenderer.BeginText(FontRectangle bounds)
-        {
-            this.BeginText(bounds);
-        }
+        void IGlyphRenderer.BeginText(FontRectangle bounds) => this.BeginText(bounds);
 
         /// <inheritdoc/>
         bool IGlyphRenderer.BeginGlyph(FontRectangle bounds, GlyphRendererParameters paramaters)
@@ -58,10 +51,7 @@ bool IGlyphRenderer.BeginGlyph(FontRectangle bounds, GlyphRendererParameters par
         /// <summary>
         /// Begins the figure.
         /// </summary>
-        void IGlyphRenderer.BeginFigure()
-        {
-            this.builder.StartFigure();
-        }
+        void IGlyphRenderer.BeginFigure() => this.builder.StartFigure();
 
         /// <summary>
         /// Draws a cubic bezier from the current point  to the <paramref name="point"/>
@@ -78,18 +68,12 @@ void IGlyphRenderer.CubicBezierTo(Vector2 secondControlPoint, Vector2 thirdContr
         /// <summary>
         /// Ends the glyph.
         /// </summary>
-        void IGlyphRenderer.EndGlyph()
-        {
-            this.paths.Add(this.builder.Build());
-        }
+        void IGlyphRenderer.EndGlyph() => this.paths.Add(this.builder.Build());
 
         /// <summary>
         /// Ends the figure.
         /// </summary>
-        void IGlyphRenderer.EndFigure()
-        {
-            this.builder.CloseFigure();
-        }
+        void IGlyphRenderer.EndFigure() => this.builder.CloseFigure();
 
         /// <summary>
         /// Draws a line from the current point  to the <paramref name="point"/>.
@@ -123,14 +107,14 @@ void IGlyphRenderer.QuadraticBezierTo(Vector2 secondControlPoint, Vector2 point)
         }
 
         /// <summary>Called before any glyphs have been rendered.</summary>
-        /// <param name="rect">The bounds the text will be rendered at and at whats size.</param>
-        protected virtual void BeginText(FontRectangle rect)
+        /// <param name="bounds">The bounds the text will be rendered at and at what size.</param>
+        protected virtual void BeginText(FontRectangle bounds)
         {
         }
 
         /// <summary>Begins the glyph.</summary>
-        /// <param name="rect">The bounds the glyph will be rendered at and at what size.</param>
-        protected virtual void BeginGlyph(FontRectangle rect)
+        /// <param name="bounds">The bounds the glyph will be rendered at and at what size.</param>
+        protected virtual void BeginGlyph(FontRectangle bounds)
         {
         }
     }

src/ImageSharp.Drawing/Shapes/Text/PathGlyphBuilder.cs

@@ -15,16 +15,14 @@ internal sealed class PathGlyphBuilder : GlyphBuilder
     {
         private const float Pi = MathF.PI;
         private readonly IPathInternals path;
-        private readonly bool isVerticalLayout;
         private float xOffset;
         private float yOffset;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="PathGlyphBuilder"/> class.
         /// </summary>
         /// <param name="path">The path to render the glyphs along.</param>
-        /// <param name="layoutMode">The mode to determine the layout of the text.</param>
-        public PathGlyphBuilder(IPath path, LayoutMode layoutMode)
+        public PathGlyphBuilder(IPath path)
         {
             if (path is IPathInternals internals)
             {
@@ -34,76 +32,35 @@ public PathGlyphBuilder(IPath path, LayoutMode layoutMode)
             {
                 this.path = new ComplexPolygon(path);
             }
-
-            this.isVerticalLayout = IsVertical(layoutMode);
         }
 
         /// <inheritdoc/>
-        protected override void BeginText(FontRectangle rect)
+        protected override void BeginText(FontRectangle bounds)
         {
-            // TODO: This uses the baseline of the text, should it be the bottom?
-            this.yOffset = rect.Height;
-            this.xOffset = rect.Left;
+            this.yOffset = bounds.Bottom;
+            this.xOffset = bounds.Left;
         }
 
         /// <inheritdoc/>
-        protected override void BeginGlyph(FontRectangle rect)
-        {
-            // https://svgwg.org/svg2-draft/text.html#TextpathLayoutRules
-            if (this.isVerticalLayout)
-            {
-                this.TransformGlyphVertical(rect);
-            }
-            else
-            {
-                this.TransformGlyphHorizontal(rect);
-            }
-        }
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private void TransformGlyphHorizontal(FontRectangle rect)
-        {
-            // Find the intersection point. Bottom-centre for horizontal text.
-            float halfWidth = rect.Width * .5F;
-            Vector2 intersectionPoint = new(rect.Left + halfWidth, rect.Bottom);
-
-            // Find the point of this intersection along the given path. This ensures the correct rotation.
-            SegmentInfo point = this.path.PointAlongPath(intersectionPoint.X - this.xOffset);
-
-            // Now offset our target point since we're aligning top-left.
-            Vector2 targetPoint = point.Point + new PointF(-halfWidth, intersectionPoint.Y - rect.Height - this.yOffset);
-
-            // Due to how matrix combining works you have to combine this in the reverse order of operation
-            // this one rotates the glype then moves it.
-            Matrix3x2 matrix = Matrix3x2.CreateTranslation(targetPoint - rect.Location) * Matrix3x2.CreateRotation(point.Angle - Pi, point.Point);
-            this.builder.SetTransform(matrix);
-        }
+        protected override void BeginGlyph(FontRectangle bounds) => this.TransformGlyph(bounds);
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private void TransformGlyphVertical(FontRectangle rect)
+        private void TransformGlyph(FontRectangle bounds)
         {
-            // TODO: Fix this.
-            // Find the intersection point. Centre-centre for vertical text.
-            float halfWidth = rect.Width * .5F;
-            float halfHeight = rect.Height * .5F;
-            Vector2 intersectionPoint = new(rect.Left + halfWidth, rect.Top + halfHeight);
+            // Find the intersection point. This should be offset to ensure we rotate at the center of the glyph.
+            float halfWidth = (bounds.Right - bounds.Left) * .5F;
+            Vector2 intersectPoint = new(bounds.Left + halfWidth, bounds.Top);
 
-            SegmentInfo point = this.path.PointAlongPath(intersectionPoint.X - this.xOffset);
+            // Find the point of this intersection along the given path.
+            SegmentInfo pathPoint = this.path.PointAlongPath(intersectPoint.X - this.xOffset);
 
-            // Now offset our target point since we're aligning top-left.
-            Vector2 targetPoint = point.Point + new PointF(-halfWidth, intersectionPoint.Y - halfHeight - this.yOffset);
+            // Now offset our target point since we're aligning the bottom-left location of our glyph against the path.
+            Vector2 targetPoint = pathPoint.Point + new PointF(-halfWidth, intersectPoint.Y - this.yOffset);
 
-            // Due to how matrix combining works you have to combine this in the reverse order of operation
-            // this one rotates the glype then moves it.
-            Matrix3x2 matrix = Matrix3x2.CreateTranslation(targetPoint - rect.Location) * Matrix3x2.CreateRotation(point.Angle - Pi, point.Point);
+            // Due to how matrix combining works you have to combine this in the reverse order of operation.
+            // First rotate the glyph then move it.
+            Matrix3x2 matrix = Matrix3x2.CreateTranslation(targetPoint - bounds.Location) * Matrix3x2.CreateRotation(pathPoint.Angle - Pi, pathPoint.Point);
             this.builder.SetTransform(matrix);
         }
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static bool IsVertical(LayoutMode mode)
-        {
-            const LayoutMode vertical = LayoutMode.VerticalLeftRight | LayoutMode.VerticalRightLeft;
-            return (mode & vertical) > 0;
-        }
     }
 }

src/ImageSharp.Drawing/Shapes/Text/TextBuilder.cs

@@ -36,7 +36,7 @@ public static IPathCollection GenerateGlyphs(string text, TextOptions textOption
         /// <returns>The <see cref="IPathCollection"/></returns>
         public static IPathCollection GenerateGlyphs(string text, IPath path, TextOptions textOptions)
         {
-            PathGlyphBuilder glyphBuilder = new(path, textOptions.LayoutMode);
+            PathGlyphBuilder glyphBuilder = new(path);
             TextRenderer renderer = new(glyphBuilder);
 
             renderer.RenderText(text, textOptions);