Created text measuring algorithm for shaped text via HarfBuzz

QuestPDF.Examples/TextShapingTests.cs

@@ -0,0 +1,101 @@
+using System;
+using System.Linq;
+using NUnit.Framework;
+using QuestPDF.Drawing;
+using QuestPDF.Examples.Engine;
+using QuestPDF.Fluent;
+using QuestPDF.Helpers;
+using QuestPDF.Infrastructure;
+using SkiaSharp;
+using SkiaSharp.HarfBuzz;
+
+namespace QuestPDF.Examples
+{
+    public class TextShapingTests
+    {
+        [Test]
+        public void ShapeText()
+        {
+            using var textPaint = new SKPaint
+            {
+                Color = SKColors.Black,
+                Typeface = SKTypeface.CreateDefault(),
+                IsAntialias = true,
+                TextSize = 20
+            };
+            
+            using var backgroundPaint = new SKPaint
+            {
+                Color = SKColors.LightGray
+            };
+            
+            RenderingTest
+                .Create()
+                .PageSize(550, 250)
+                .ProduceImages()
+                .ShowResults()
+                .Render(container =>
+                {
+                    //var lorem = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec odio ipsum, aliquam a neque a, lacinia vehicula lectus.";
+                    //var arabic = "ينا الألم. في بعض الأحيان ونظراً للالتزامات التي يفرضها علينا الواجب والعمل سنتنازل غالباً ونرفض الشعور";
+                    
+                    var lorem = "Lorem ipsum dolor sit amet, consectetur adipiscing elit.";
+                    var arabic = "ينا الألم. في بعض الأحيان ونظراً للالتزامات التي يفرضها علينا";
+                    
+                    var text = arabic;
+                    var metrics = textPaint.FontMetrics;
+                    
+                    container
+                        .Padding(25)
+                        .Canvas((canvas, space) =>
+                        {
+                            canvas.Translate(0, 20);
+                            
+                            var width = MeasureText(text, textPaint);
+                            var widthReal = textPaint.MeasureText(text);
+                            canvas.DrawRect(0, metrics.Descent, width, metrics.Ascent - metrics.Descent, backgroundPaint);
+                            
+                            canvas.DrawShapedText(text, 0, 0, textPaint);
+                            
+                            canvas.Translate(0, 40);
+                            canvas.DrawText(text, 0, 0, textPaint);
+                        });
+                });
+        }
+        
+        float MeasureText(string text, SKPaint paint)
+        {
+            var font = paint.ToFont();
+            using var shaper = new SKShaper(paint.Typeface);
+            var result = shaper.Shape(text + " ", paint);
+            return Math.Max(result.Points.First().X, result.Points.Last().X);
+
+            var glyphCount = result.Codepoints.Length;
+            var glyphIds = new ushort[glyphCount];
+            var glyphWidths = new float[glyphCount];
+            var glyphBounds = new SKRect[glyphCount];
+            
+            font.GetGlyphs(result.Codepoints.Select(x => (int)x).ToArray(), glyphIds);
+            font.GetGlyphWidths(glyphIds, glyphWidths, glyphBounds);
+
+            return glyphWidths.Sum();
+            
+            return result.Points.Max(p => p.X);
+
+            using var skTextBlobBuilder = new SKTextBlobBuilder();
+
+            var positionedRunBuffer = skTextBlobBuilder.AllocatePositionedRun(font, result.Codepoints.Length);
+            var glyphSpan = positionedRunBuffer.GetGlyphSpan();
+            var positionSpan = positionedRunBuffer.GetPositionSpan();
+            
+            for (int index = 0; index < result.Codepoints.Length; ++index)
+            {
+                glyphSpan[index] = (ushort) result.Codepoints[index];
+                positionSpan[index] = result.Points[index];
+            }
+
+            using var text1 = skTextBlobBuilder.Build();
+            return text1.Bounds.Width;
+        }
+    }
+}

QuestPDF/Drawing/FontManager.cs

@@ -12,6 +12,7 @@ namespace QuestPDF.Drawing
         private static ConcurrentDictionary<string, FontStyleSet> StyleSets = new();
         private static ConcurrentDictionary<object, SKFontMetrics> FontMetrics = new();
         private static ConcurrentDictionary<object, SKPaint> Paints = new();
+        private static ConcurrentDictionary<object, SKFont> Fonts = new();
         private static ConcurrentDictionary<string, SKPaint> ColorPaint = new();
 
         private static void RegisterFontType(SKData fontData, string? customName = null)
@@ -94,6 +95,11 @@ namespace QuestPDF.Drawing
             }
         }
 
+        internal static SKFont ToFont(this TextStyle style)
+        {
+            return Fonts.GetOrAdd(style.FontMetricsKey, _ => style.ToPaint().Typeface.ToFont());
+        }
+        
         internal static SKFontMetrics ToFontMetrics(this TextStyle style)
         {
             return FontMetrics.GetOrAdd(style.FontMetricsKey, key => style.ToPaint().FontMetrics);

QuestPDF/Drawing/SkiaCanvasBase.cs

@@ -1,5 +1,6 @@
 using QuestPDF.Infrastructure;
 using SkiaSharp;
+using SkiaSharp.HarfBuzz;
 
 namespace QuestPDF.Drawing
 {
@@ -29,7 +30,7 @@ namespace QuestPDF.Drawing
 
         public void DrawText(string text, Position vector, TextStyle style)
         {
-            Canvas.DrawText(text, vector.X, vector.Y, style.ToPaint());
+            Canvas.DrawShapedText(text, vector.X, vector.Y, style.ToPaint());
         }
 
         public void DrawImage(SKImage image, Position vector, Size size)

QuestPDF/Elements/Text/Items/TextBlockSpan.cs

@@ -11,8 +11,7 @@ namespace QuestPDF.Elements.Text.Items
         public string Text { get; set; }
         public TextStyle Style { get; set; } = new TextStyle();
 
-        private Dictionary<(int startIndex, float availableWidth), TextMeasurementResult?> MeasureCache =
-            new Dictionary<(int startIndex, float availableWidth), TextMeasurementResult?>();
+        private Dictionary<(int startIndex, float availableWidth), TextMeasurementResult?> MeasureCache = new();
 
         public virtual TextMeasurementResult? Measure(TextMeasurementRequest request)
         {
@@ -88,7 +87,7 @@ namespace QuestPDF.Elements.Text.Items
             
             // measure final text
             var width = paint.MeasureText(text);
-            
+  
             return new TextMeasurementResult
             {
                 Width = width,
@@ -104,7 +103,6 @@ namespace QuestPDF.Elements.Text.Items
                 TotalIndex = Text.Length
             };
         }
-        
         public virtual void Draw(TextDrawingRequest request)
         {
             var fontMetrics = Style.ToFontMetrics();

QuestPDF/QuestPDF.csproj

@@ -25,6 +25,7 @@
 
     <ItemGroup>
       <PackageReference Include="SkiaSharp" Version="2.80.3" />
+      <PackageReference Include="SkiaSharp.HarfBuzz" Version="2.80.3" />
     </ItemGroup>
 
     <ItemGroup>