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Add support for multi-line text to SkiaRenderContext (#1538)
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‎CHANGELOG.md‎

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@@ -26,6 +26,7 @@ All notable changes to this project will be documented in this file.
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- WindowsForms ExampleBrowser can display transposed versions of examples (#1535)
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- Example for Issue #1545 showing the use of different line endings
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- Support for unix line endings in OxyPlot.ImageSharp, OxyPlot.Svg, and OxyPlot.Pdf (#1545)
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- Multi-Line Text support to SkiaRenderContext (#1538)
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### Changed
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- Legends model (#644)

‎Source/Examples/ExampleLibrary/Examples/RenderingCapabilities.cs‎

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@@ -262,6 +262,32 @@ public static PlotModel DrawTextAlignmentRotation()
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return model;
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}
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/// <summary>
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/// Shows multi-line alignment capabilities for the DrawText method.
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/// </summary>
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/// <returns>A plot model.</returns>
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[Example("DrawText - Multi-line Alignment/Rotation")]
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public static PlotModel DrawMultilineTextAlignmentRotation()
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{
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var model = new PlotModel();
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model.Annotations.Add(new DelegateAnnotation(rc =>
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{
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for (var ha = HorizontalAlignment.Left; ha <= HorizontalAlignment.Right; ha++)
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{
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for (var va = VerticalAlignment.Top; va <= VerticalAlignment.Bottom; va++)
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{
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var origin = new ScreenPoint(((int)ha + 2) * 170, ((int)va + 2) * 170);
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rc.FillCircle(origin, 3, OxyColors.Blue, EdgeRenderingMode.Adaptive);
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for (var rotation = 0; rotation < 360; rotation += 90)
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{
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rc.DrawText(origin, $"R{rotation:000}\n{ha}\n{va}", OxyColors.Black, fontSize: 20d, rotation: rotation, horizontalAlignment: ha, verticalAlignment: va);
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}
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}
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}
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}));
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return model;
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}
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/// <summary>
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/// Shows color capabilities for the DrawText method.
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/// </summary>

‎Source/OxyPlot.SkiaSharp.Tests/OxyPlot.SkiaSharp.Tests.csproj‎

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@@ -7,6 +7,7 @@
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<Copyright>OxyPlot contributors</Copyright>
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<TreatWarningsAsErrors>true</TreatWarningsAsErrors>
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<Platforms>AnyCPU;x86;x64</Platforms>
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<LangVersion>8</LangVersion>
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</PropertyGroup>
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<PropertyGroup Condition="'$(TargetFramework)|$(Platform)'=='net461|AnyCPU'">
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<PlatformTarget>x86</PlatformTarget>

‎Source/OxyPlot.SkiaSharp.Tests/SvgExporterTests.cs‎

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@@ -6,6 +6,7 @@
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namespace OxyPlot.SkiaSharp.Tests
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{
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using ExampleLibrary;
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using NUnit.Framework;
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using OxyPlot.SkiaSharp;
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using System.IO;
@@ -24,6 +25,15 @@ public void Export_SomeExamplesInExampleLibrary_CheckThatAllFilesExist()
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ExportTest.Export_FirstExampleOfEachExampleGroup_CheckThatAllFilesExist(exporter, directory, ".svg");
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}
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[Test]
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public void TestMultilineAlignment()
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{
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var exporter = new SvgExporter { Width = 1000, Height = 750 };
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var model = RenderingCapabilities.DrawMultilineTextAlignmentRotation();
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using var stream = File.Create(Path.Combine(this.outputDirectory, "Multiline-Alignment.svg"));
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exporter.Export(model, stream);
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}
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[OneTimeSetUp]
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public void Setup()
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{

‎Source/OxyPlot.SkiaSharp/SkiaRenderContext.cs‎

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@@ -354,44 +354,51 @@ public void DrawText(
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var x = this.Convert(p.X);
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var y = this.Convert(p.Y);
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var metrics = paint.FontMetrics;
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var lines = StringHelper.SplitLines(text);
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var lineHeight = paint.GetFontMetrics(out var metrics);
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var deltaY = verticalAlignment switch
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{
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VerticalAlignment.Top => -metrics.Ascent,
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VerticalAlignment.Middle => -(metrics.Ascent + metrics.Descent) / 2,
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VerticalAlignment.Bottom => -metrics.Descent,
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VerticalAlignment.Middle => -(metrics.Ascent + metrics.Descent + lineHeight * (lines.Length - 1)) / 2,
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VerticalAlignment.Bottom => -metrics.Descent - lineHeight * (lines.Length - 1),
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_ => throw new ArgumentOutOfRangeException(nameof(verticalAlignment))
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};
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using var _ = new SKAutoCanvasRestore(this.SkCanvas);
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this.SkCanvas.Translate(x, y);
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this.SkCanvas.RotateDegrees((float)rotation);
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if (this.UseTextShaping)
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foreach (var line in lines)
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{
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var width = this.MeasureText(text, shaper, paint);
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var deltaX = horizontalAlignment switch
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if (this.UseTextShaping)
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{
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HorizontalAlignment.Left => 0,
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HorizontalAlignment.Center => -width / 2,
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HorizontalAlignment.Right => -width,
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_ => throw new ArgumentOutOfRangeException(nameof(horizontalAlignment))
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};
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this.paint.TextAlign = SKTextAlign.Left;
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this.SkCanvas.DrawShapedText(shaper, text, deltaX, deltaY, paint);
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}
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else
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{
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paint.TextAlign = horizontalAlignment switch
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var width = this.MeasureText(line, shaper, paint);
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var deltaX = horizontalAlignment switch
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{
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HorizontalAlignment.Left => 0,
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HorizontalAlignment.Center => -width / 2,
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HorizontalAlignment.Right => -width,
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_ => throw new ArgumentOutOfRangeException(nameof(horizontalAlignment))
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};
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this.paint.TextAlign = SKTextAlign.Left;
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this.SkCanvas.DrawShapedText(shaper, line, deltaX, deltaY, paint);
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}
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else
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{
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HorizontalAlignment.Left => SKTextAlign.Left,
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HorizontalAlignment.Center => SKTextAlign.Center,
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HorizontalAlignment.Right => SKTextAlign.Right,
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_ => throw new ArgumentOutOfRangeException(nameof(horizontalAlignment))
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};
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paint.TextAlign = horizontalAlignment switch
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{
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HorizontalAlignment.Left => SKTextAlign.Left,
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HorizontalAlignment.Center => SKTextAlign.Center,
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HorizontalAlignment.Right => SKTextAlign.Right,
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_ => throw new ArgumentOutOfRangeException(nameof(horizontalAlignment))
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};
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this.SkCanvas.DrawText(text, 0, deltaY, paint);
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this.SkCanvas.DrawText(line, 0, deltaY, paint);
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}
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deltaY += lineHeight;
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}
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}
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@@ -403,9 +410,11 @@ public OxySize MeasureText(string text, string fontFamily = null, double fontSiz
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return new OxySize(0, 0);
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}
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var lines = StringHelper.SplitLines(text);
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var paint = this.GetTextPaint(fontFamily, fontSize, fontWeight, out var shaper);
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var width = this.MeasureText(text, shaper, paint);
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var height = paint.GetFontMetrics(out _);
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var height = paint.GetFontMetrics(out _) * lines.Length;
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var width = lines.Max(line => this.MeasureText(line, shaper, paint));
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return new OxySize(this.ConvertBack(width), this.ConvertBack(height));
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}
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