In the previous post, you have seen how to use Aspose.Font for .NET API for loading and saving CFF, TrueType, and Type1 fonts programmatically. In this article, you will learn how to render text with TrueType and Type1 font using C#. The code samples will show you how to generate a JPG image based on the provided text.
- .NET Font Rendering API - Installation
- Implement Text Rendering Interface
- Render Text with TrueType Font using C#
- Render Text with Type1 Font using C#
.NET Font Rendering API - Installation
Aspose.Font for .NET provides a powerful font rendering mechanism in order to render the text using TrueType and Type1 fonts. You can download the API or get it installed using NuGet.
PM> Install-Package Aspose.Font
Implement Text Rendering Interface
In order to achieve the text rendering, Aspose.Font for .NET provides an IGlyphOutlinePainter interface to draw the glyphs. The following steps demonstrate how to implement the methods in IGlyphOutlinePainter.
- Implement the IGlyphOutlinePainter interface methods using GlyphOutlinePainter class which requires an object of type System.Drawing.Drawing2D.GraphicsPath for drawing graphics.
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| // For complete examples and data files, please go to https://github.com/aspose-font/Aspose.Font-for-.NET | |
| class GlyphOutlinePainter : IGlyphOutlinePainter | |
| { | |
| private System.Drawing.Drawing2D.GraphicsPath _path; | |
| private System.Drawing.PointF _currentPoint; | |
| public GlyphOutlinePainter(System.Drawing.Drawing2D.GraphicsPath path) | |
| { | |
| _path = path; | |
| } | |
| public void MoveTo(MoveTo moveTo) | |
| { | |
| _path.CloseFigure(); | |
| _currentPoint.X = (float)moveTo.X; | |
| _currentPoint.Y = (float)moveTo.Y; | |
| } | |
| public void LineTo(LineTo lineTo) | |
| { | |
| float x = (float)lineTo.X; | |
| float y = (float)lineTo.Y; | |
| _path.AddLine(_currentPoint.X, _currentPoint.Y, x, y); | |
| _currentPoint.X = x; | |
| _currentPoint.Y = y; | |
| } | |
| public void CurveTo(CurveTo curveTo) | |
| { | |
| float x3 = (float)curveTo.X3; | |
| float y3 = (float)curveTo.Y3; | |
| _path.AddBezier( | |
| _currentPoint.X, | |
| _currentPoint.Y, | |
| (float)curveTo.X1, | |
| (float)curveTo.Y1, | |
| (float)curveTo.X2, | |
| (float)curveTo.Y2, | |
| x3, | |
| y3); | |
| _currentPoint.X = x3; | |
| _currentPoint.Y = y3; | |
| } | |
| public void ClosePath() | |
| { | |
| _path.CloseFigure(); | |
| } | |
| } |
- Create a new method DrawText() to draw the text into System.Drawing.Bitmap object.
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| // For complete examples and data files, please go to https://github.com/aspose-font/Aspose.Font-for-.NET | |
| static void DrawText(string text, IFont font, double fontSize, | |
| Brush backgroundBrush, Brush textBrush, string outFile) | |
| { | |
| //Get glyph identifiers for every symbol in text line | |
| GlyphId[] gids = new GlyphId[text.Length]; | |
| for (int i = 0; i < text.Length; i++) | |
| gids[i] = font.Encoding.DecodeToGid(text[i]); | |
| // set common drawing settings | |
| double dpi = 300; | |
| double resolutionCorrection = dpi / 72; // 72 is font's internal dpi | |
| // prepare output bitmap | |
| Bitmap outBitmap = new Bitmap(960, 720); | |
| outBitmap.SetResolution((float)dpi, (float)dpi); | |
| Graphics outGraphics = Graphics.FromImage(outBitmap); | |
| outGraphics.FillRectangle(backgroundBrush, 0, 0, outBitmap.Width, outBitmap.Height); | |
| outGraphics.SmoothingMode = SmoothingMode.HighQuality; | |
| //declare coordinate variables and previous gid | |
| GlyphId previousGid = null; | |
| double glyphXCoordinate = 0; | |
| double glyphYCoordinate = fontSize * resolutionCorrection; | |
| //loop which paints every glyph in gids | |
| foreach (GlyphId gid in gids) | |
| { | |
| // if the font contains the gid | |
| if (gid != null) | |
| { | |
| Glyph glyph = font.GlyphAccessor.GetGlyphById(gid); | |
| if (glyph == null) | |
| continue; | |
| // path that accepts drawing instructions | |
| GraphicsPath path = new GraphicsPath(); | |
| // Create IGlyphOutlinePainter implementation | |
| GlyphOutlinePainter outlinePainter = new GlyphOutlinePainter(path); | |
| // Create the renderer | |
| Aspose.Font.Renderers.IGlyphRenderer renderer = new | |
| Aspose.Font.Renderers.GlyphOutlineRenderer(outlinePainter); | |
| // get common glyph properties | |
| double kerning = 0; | |
| // get kerning value | |
| if (previousGid != null) | |
| { | |
| kerning = (font.Metrics.GetKerningValue(previousGid, gid) / | |
| glyph.SourceResolution) * fontSize * resolutionCorrection; | |
| kerning += FontWidthToImageWith(font.Metrics.GetGlyphWidth(previousGid), | |
| glyph.SourceResolution, fontSize); | |
| } | |
| // glyph positioning - increase glyph X coordinate according to kerning distance | |
| glyphXCoordinate += kerning; | |
| // Glyph placement matrix | |
| TransformationMatrix glyphMatrix = | |
| new TransformationMatrix( | |
| new double[] | |
| { | |
| fontSize*resolutionCorrection, | |
| 0, | |
| 0, | |
| // negative because of bitmap coordinate system begins from the top | |
| - fontSize*resolutionCorrection, | |
| glyphXCoordinate, | |
| glyphYCoordinate | |
| }); | |
| // render current glyph | |
| renderer.RenderGlyph(font, gid, glyphMatrix); | |
| // fill the path | |
| path.FillMode = FillMode.Winding; | |
| outGraphics.FillPath(textBrush, path); | |
| } | |
| //set current gid as previous to get correct kerning for next glyph | |
| previousGid = gid; | |
| } | |
| //Save results | |
| outBitmap.Save(outFile); | |
| } |
- Define a utility method to calculate the font’s width according to the image’s width.
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| // For complete examples and data files, please go to https://github.com/aspose-font/Aspose.Font-for-.NET | |
| static double FontWidthToImageWith(double width, int fontSourceResulution, double fontSize, double dpi = 300) | |
| { | |
| double resolutionCorrection = dpi / 72; // 72 is font's internal dpi | |
| return (width / fontSourceResulution) * fontSize * resolutionCorrection; | |
| } |
Render Text with TrueType Font using C#
The following code sample shows how to use the above-mentioned implementation to render text with a TrueType font using C#.
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| // For complete examples and data files, please go to https://github.com/aspose-font/Aspose.Font-for-.NET | |
| string dataDir = RunExamples.GetDataDir_Data(); | |
| string fileName1 = dataDir + "Montserrat-Bold.ttf"; //Font file name with full path | |
| FontDefinition fd1 = new FontDefinition(FontType.TTF, new FontFileDefinition("ttf", new FileSystemStreamSource(fileName1))); | |
| TtfFont ttfFont1 = Aspose.Font.Font.Open(fd1) as TtfFont; | |
| string fileName2 = dataDir + "Lora-Bold.ttf"; //Font file name with full path | |
| FontDefinition fd2 = new FontDefinition(FontType.TTF, new FontFileDefinition("ttf", new FileSystemStreamSource(fileName2))); | |
| TtfFont ttfFont2 = Aspose.Font.Font.Open(fd2) as TtfFont; | |
| DrawText("Hello world", ttfFont1, 14, Brushes.White, Brushes.Black, dataDir + "hello1_montserrat_out.jpg"); | |
| DrawText("Hello world", ttfFont2, 14, Brushes.Yellow, Brushes.Red, dataDir + "hello2_lora_out.jpg"); |
Render Text with Type1 Font using C#
The following code sample shows how to render text with a Type1 font using C#.
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| // For complete examples and data files, please go to https://github.com/aspose-font/Aspose.Font-for-.NET | |
| string fileName = dataDir + "courier.pfb"; //Font file name with full path | |
| FontDefinition fd = new FontDefinition(FontType.Type1, new FontFileDefinition("pfb", new FileSystemStreamSource(fileName))); | |
| Type1Font font = Aspose.Font.Font.Open(fd) as Type1Font; | |
| DrawText("Hello world", font, 14, Brushes.White, Brushes.Black, dataDir + "hello1_type1_out.jpg"); | |
| DrawText("Hello world", font, 14, Brushes.Yellow, Brushes.Red, dataDir + "hello2_type1_out.jpg"); |
Conclusion
In this article, you have learned how to implement the rendering of text with a TrueType or Type1 font using C#. The code samples have shown how to generate JPG images based on the provided text. You can explore more about Aspose.Font for .NET using the documentation.