SkiaSharp 是一个强大的跨平台 2D 图形库，提供了丰富的文本渲染功能。本文将详细介绍如何使用 SkiaSharp 进行文本渲染，并涵盖从基础到高级的各种技术。

Nuget 安装包

C#
SkiaSharp
SkiaSharp.Views.WindowsForms

基本文本渲染

简单文本绘制

C#
using SkiaSharp;
using SkiaSharp.Views.Desktop;

namespace AppFont
{
    public partial class Form1 : Form
    {
        private SKGLControl skControl;
        public Form1()
        {
            InitializeComponent();

            skControl=new SKGLControl();
            skControl.Dock=DockStyle.Fill;
            this.Controls.Add(skControl);

            skControl.PaintSurface += SkControl_PaintSurface;
        }

        private void SkControl_PaintSurface(object? sender, SKPaintGLSurfaceEventArgs e)
        {
            SKCanvas canvas = e.Surface.Canvas;
            canvas.Clear(SKColors.White);
            DrawSimpleText(canvas);
        }

        public void DrawSimpleText(SKCanvas canvas)
        {
            // 创建画笔
            using var paint = new SKPaint
            {
                Color = SKColors.Black,        // 文字颜色
                TextSize = 24,                 // 文字大小
                IsAntialias = true,            // 抗锯齿
                Typeface = SKTypeface.Default  // 默认字体
            };

            // 绘制文本
            canvas.DrawText("Hello, SkiaSharp!", 50, 100, paint);
        }
    }
}

文本对齐与基线

C#
using SkiaSharp;
using SkiaSharp.Views.Desktop;

namespace AppFont
{
    public partial class Form1 : Form
    {
        private SKGLControl skControl;
        public Form1()
        {
            InitializeComponent();

            skControl=new SKGLControl();
            skControl.Dock=DockStyle.Fill;
            this.Controls.Add(skControl);

            skControl.PaintSurface += SkControl_PaintSurface;
        }

        private void SkControl_PaintSurface(object? sender, SKPaintGLSurfaceEventArgs e)
        {
            SKCanvas canvas = e.Surface.Canvas;
            canvas.Clear(SKColors.White);
            DrawTextWithAlignment(canvas, e.BackendRenderTarget.Width);
        }
        public void DrawTextWithAlignment(SKCanvas canvas, int width)
        {
            using var paint = new SKPaint
            {
                IsAntialias = true,
                Color = SKColors.Blue,
                TextSize = 36,
                TextAlign = SKTextAlign.Center  // 文本居中对齐
            };

            // 绘制居中文本
            canvas.DrawText("Centered Text", width / 2, 200, paint);
        }
    }
}

高级文本渲染技术

自定义字体

C#
using SkiaSharp;
using SkiaSharp.Views.Desktop;

namespace AppFont
{
    public partial class Form1 : Form
    {
        private SKGLControl skControl;
        public Form1()
        {
            InitializeComponent();

            skControl=new SKGLControl();
            skControl.Dock=DockStyle.Fill;
            this.Controls.Add(skControl);

            skControl.PaintSurface += SkControl_PaintSurface;
        }

        private void SkControl_PaintSurface(object? sender, SKPaintGLSurfaceEventArgs e)
        {
            SKCanvas canvas = e.Surface.Canvas;
            canvas.Clear(SKColors.White);
            DrawCustomFont(canvas);
        }
        public void DrawCustomFont(SKCanvas canvas)
        {
            // 从文件加载自定义字体
            using var typeface = SKTypeface.FromFile("华文彩云.ttf");

            using var paint = new SKPaint
            {
                IsAntialias = true,
                Color = SKColors.DarkGreen,
                TextSize = 48,
                Typeface = typeface
            };

            canvas.DrawText("Custom Font", 50, 300, paint);
        }
    }
}

文本样式与特效

C#
public void DrawStyledText(SKCanvas canvas)
{
    using var paint = new SKPaint
    {
        Color = SKColors.Red,
        TextSize = 40,
        IsAntialias = true,
        
        // 文字样式
        Style = SKPaintStyle.Stroke,  // 描边模式
        StrokeWidth = 2,               // 描边宽度
        
        // 阴影效果
        MaskFilter = SKMaskFilter.CreateBlur(SKBlurStyle.Normal, 3)
    };

    canvas.DrawText("Styled Text", 50, 400, paint);
}

文本测量与布局

文本度量

C#
public void MeasureText(SKCanvas canvas)
{
    using var paint = new SKPaint { TextSize = 30 };
    
    string text = "Text Measurement";
    
    // 获取文本宽度
    float textWidth = paint.MeasureText(text);
    
    // 获取文本边界
    SKRect bounds = new SKRect();
    paint.MeasureText(text, ref bounds);

    Console.WriteLine($"Text Width: {textWidth}");
    Console.WriteLine($"Text Bounds: {bounds}");
}

多行文本渲染

C#
public void DrawMultilineText(SKCanvas canvas)
{
    string[] lines = {
        "First line of text",
        "Second line of text",
        "Third line of text"
    };

    using var paint = new SKPaint
    {
        Color = SKColors.Purple,
        TextSize = 24
    };

    float lineHeight = paint.TextSize * 1.5f;
    
    for (int i = 0; i < lines.Length; i++)
    {
        canvas.DrawText(
            lines[i], 
            50, 
            100 + (i * lineHeight), 
            paint
        );
    }
}

文本特殊效果

文字路径

C#
public void CreateTextPath(SKCanvas canvas)
{
    string text = "Path Text";
    
    using var paint = new SKPaint
    {
        Color = SKColors.Orange,
        TextSize = 60,
        Style = SKPaintStyle.Stroke,
        StrokeWidth = 3
    };

    // 将文字转换为路径
    using var textPath = paint.GetTextPath(text, 50, 500);
    
    // 绘制文字路径
    canvas.DrawPath(textPath, paint);
}

性能与最佳实践

尽可能重用 SKPaint 对象
对于静态文本，考虑使用 SKTextBlob
启用抗锯齿提高文本渲染质量
选择合适的字体和大小

跨平台注意事项

确保字体在不同平台兼容
使用系统无关的字体（如 OpenType）
处理字体回退机制

结语

SkiaSharp 提供了强大且灵活的文本渲染能力，通过合理使用其API，可以创建出既精美又高性能的文本图形。要充分利用这些功能，掌握以下几个关键技巧至关重要：首先，灵活运用 SKPaint 对象来控制文本样式和渲染效果；其次，深入理解文本度量的概念，以精确控制文本布局；再者，学会路径转换技术，实现文本与图形间的无缝结合；最后，在整个过程中始终注重性能优化，确保应用流畅运行。通过以上方法，开发者能够极大提升使用SkiaSharp进行文本渲染时的效果和效率。

目录