文本渲染基础

SkiaSharp 提供了丰富的文本渲染和特效能力，让开发者可以创造出极具视觉吸引力的文字效果。本文将深入探讨 SkiaSharp 中文本特效的各种技巧和方法。

Nuget 安装包

C#
SkiaSharp
SkiaSharp.Views.WindowsForms

基本文本绘制

C#
public void DrawSimpleText(SKCanvas canvas)
{
    // 创建画笔
    using var paint = new SKPaint
    {
        TextSize = 50,
        Color = SKColors.Black,
        IsAntialias = true,
        Typeface = SKTypeface.FromFamilyName("Arial")
    };

    // 绘制基础文本
    canvas.DrawText("Hello SkiaSharp", 50, 100, paint);
}

文本特效详解

渐变文字效果

C#
public void DrawGradientText(SKCanvas canvas)
{
    // 创建线性渐变
    var shader = SKShader.CreateLinearGradient(
        new SKPoint(0, 0),
        new SKPoint(200, 0),
        new SKColor[] { 
            SKColors.Blue, 
            SKColors.Purple 
        },
        null,
        SKShaderTileMode.Clamp
    );

    using var paint = new SKPaint
    {
        TextSize = 80,
        Shader = shader,
        IsAntialias = true
    };

    canvas.DrawText("test font", 50, 200, paint);
}

阴影文字效果

C#
public void DrawShadowText(SKCanvas canvas)
{
    // 加载支持中文的字体  
    SKTypeface typeface = SKTypeface.FromFamilyName(
        "Microsoft YaHei", // 或 "SimHei", "SimSun" 等常用中文字体  
        SKFontStyleWeight.Normal,
        SKFontStyleWidth.Normal,
        SKFontStyleSlant.Upright);

    // 阴影画笔
    using var shadowPaint = new SKPaint
    {
        Typeface = typeface, // 设置字体  
        TextSize = 70,
        Color = SKColors.Gray.WithAlpha(128),
        IsAntialias = true
    };

    // 主文字画笔
    using var textPaint = new SKPaint
    {
        Typeface = typeface, // 设置字体  
        TextSize = 70,
        Color = SKColors.DeepPink,
        IsAntialias = true
    };

    // 绘制阴影（稍微偏移）
    canvas.DrawText("阴影文字", 52, 302, shadowPaint);

    // 绘制主文字
    canvas.DrawText("阴影文字", 50, 300, textPaint);
}

描边文字效果

C#
public void DrawStrokeText(SKCanvas canvas)
{
    // 加载支持中文的字体  
    SKTypeface typeface = SKTypeface.FromFamilyName(
        "Microsoft YaHei", // 或 "SimHei", "SimSun" 等常用中文字体  
        SKFontStyleWeight.Bold,
        SKFontStyleWidth.Normal,
        SKFontStyleSlant.Upright);

    using var paint = new SKPaint
    {
        Typeface = typeface,
        TextSize = 80,
        Color = SKColors.Red,
        IsAntialias = true,
        Style = SKPaintStyle.Stroke,
        StrokeWidth = 3,
        StrokeJoin = SKStrokeJoin.Round
    };

    // 描边效果
    canvas.DrawText("this is test", 50, 300, paint);
}

模糊文字效果

C#
public void DrawBlurText(SKCanvas canvas)
{
    // 加载支持中文的字体  
    SKTypeface typeface = SKTypeface.FromFamilyName(
        "Microsoft YaHei", // 或 "SimHei", "SimSun" 等常用中文字体  
        SKFontStyleWeight.Bold,
        SKFontStyleWidth.Normal,
        SKFontStyleSlant.Upright);

    using var paint = new SKPaint
    {
        Typeface = typeface,
        TextSize = 70,
        Color = SKColors.Blue,
        IsAntialias = true
    };

    // 创建模糊遮罩
    using var filter = SKMaskFilter.CreateBlur(SKBlurStyle.Normal, 3);
    paint.MaskFilter = filter;

    canvas.DrawText("模糊文字", 50, 200, paint);
}

路径文字效果

C#
public void DrawPathText(SKCanvas canvas)
{
    // 创建路径
    var path = new SKPath();
    path.AddArc(new SKRect(50, 50, 300, 800), -90, 180);

    using var paint = new SKPaint
    {
        TextSize = 40,
        Color = SKColors.Green,
        IsAntialias = true
    };

    // 沿路径绘制文字
    canvas.DrawTextOnPath("this is test", path, 0, 20, paint);
}

高级文本特效技巧

混合特效组合

C#
public void DrawComplexTextEffect(SKCanvas canvas)
{
    using var paint = new SKPaint
    {
        TextSize = 60,
        IsAntialias = true,
        Color = SKColors.White
    };

    // 创建复合效果：渐变 + 阴影 + 描边
    var shader = SKShader.CreateLinearGradient(
        new SKPoint(0, 0),
        new SKPoint(200, 0),
        new SKColor[] { SKColors.Red, SKColors.Orange },
        null,
        SKShaderTileMode.Clamp
    );

    paint.Shader = shader;
    paint.Style = SKPaintStyle.StrokeAndFill;
    paint.StrokeWidth = 2;

    // 添加模糊效果
    paint.MaskFilter = SKMaskFilter.CreateBlur(SKBlurStyle.Normal, 1);

    canvas.DrawText("this is test", 50, 250, paint);
}

性能与注意事项

• 频繁创建和销毁 SKPaint 对象会影响性能，建议重用
• 使用 IsAntialias = true 提高文字渲染质量
• 对于复杂特效，考虑预渲染或缓存

结语

SkiaSharp 为文本渲染提供了强大且灵活的工具。通过合理运用渐变、阴影、描边等技术，您可以创造出令人惊叹的文字视觉效果。

提示：实际应用中，根据具体需求和性能要求选择合适的文本特效。