不同的文本渲染方法不会产生我想要的

Question

我正在寻找一种文本渲染方法，其中从位图初始化图形对象，在其上绘制文本，并且文本看起来像附加图像中的第一行。

有人可以解释一下可以做到这一点的方法吗？我不完全理解为什么以下方法都不能重现它：

测试字体为：Segoe UI，8.25pt

protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
{
    base.OnPaint(e);

    //drawing the string with the Graphics object the form gives us
    e.Graphics.DrawString("1. This is a test using DrawString. " + e.Graphics.TextRenderingHint.ToString(), 
                          base.Font, Brushes.Black, new Point(10, 10));

    //width used for all images
    const int width = 300;

    //drawing the string with Graphics objects initialized from bitmaps
    Bitmap bmp = new Bitmap(width, 20);
    using (Graphics gfx = Graphics.FromImage(bmp))
    {
        gfx.PageUnit = GraphicsUnit.Pixel;
        gfx.SmoothingMode = SmoothingMode.HighQuality;
        gfx.DrawString("2. This is a test using DrawString. " + gfx.TextRenderingHint.ToString(), 
                       base.Font, Brushes.Black, Point.Empty);
    }
    e.Graphics.DrawImage(bmp, new Point(10, 30));

    bmp.Dispose();
    bmp = new Bitmap(width, 20);

    using (Graphics gfx = Graphics.FromImage(bmp))
    {
        gfx.PageUnit = GraphicsUnit.Pixel;
        gfx.SmoothingMode = SmoothingMode.HighQuality;
        gfx.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAliasGridFit;
        gfx.DrawString("3. This is a test using DrawString. " + gfx.TextRenderingHint.ToString(), 
                       base.Font, Brushes.Black, Point.Empty);
    }

    e.Graphics.DrawImage(bmp, new Point(10, 50));

    bmp.Dispose();
    bmp = new Bitmap(width, 20);

    using (Graphics gfx = Graphics.FromImage(bmp))
    {
        gfx.PageUnit = GraphicsUnit.Pixel;
        gfx.SmoothingMode = SmoothingMode.HighQuality;
        gfx.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
        gfx.DrawString("4. This is a test using DrawString. " + gfx.TextRenderingHint.ToString(), 
                       base.Font, Brushes.Black, Point.Empty);
    }

    e.Graphics.DrawImage(bmp, new Point(10, 70));

    bmp.Dispose();
    bmp = new Bitmap(width, 20);

    using (Graphics gfx = Graphics.FromImage(bmp))
    {
        gfx.PageUnit = GraphicsUnit.Pixel;
        gfx.SmoothingMode = SmoothingMode.HighQuality;
        gfx.TextRenderingHint = System.Drawing.Text.TextRenderingHint.ClearTypeGridFit;
        gfx.DrawString("5. This is a test using DrawString. " + gfx.TextRenderingHint.ToString(),
                       base.Font, Brushes.Black, Point.Empty);
    }

    e.Graphics.DrawImage(bmp, new Point(10, 90));

    bmp.Dispose();
    bmp = new Bitmap(width, 20);

    using (Graphics gfx = Graphics.FromImage(bmp))
    {
        gfx.PageUnit = GraphicsUnit.Pixel;
        gfx.SmoothingMode = SmoothingMode.HighQuality;
        using (GraphicsPath path = new GraphicsPath())
        {
            path.AddString("6. This is a test using GraphicsPath. " + gfx.TextRenderingHint.ToString(), 
                           base.Font.FontFamily, (int)base.Font.Style, 
                           base.Font.Size, Point.Empty, StringFormat.GenericDefault);

            gfx.FillPath(Brushes.Black, path);
        }
    }

    e.Graphics.DrawImage(bmp, new Point(10, 110));

    bmp.Dispose();
    bmp = new Bitmap(width, 20);

    using (Graphics gfx = Graphics.FromImage(bmp))
    {
        gfx.PageUnit = GraphicsUnit.Pixel;
        gfx.SmoothingMode = SmoothingMode.HighQuality;
        gfx.TextRenderingHint = System.Drawing.Text.TextRenderingHint.ClearTypeGridFit;
        using (GraphicsPath path = new GraphicsPath())
        {
            path.AddString("7. This is a test using GraphicsPath. " + gfx.TextRenderingHint.ToString(),
                           base.Font.FontFamily, (int)base.Font.Style,
                           base.Font.Size, Point.Empty, StringFormat.GenericDefault);

            gfx.FillPath(Brushes.Black, path);
        }
    }

    e.Graphics.DrawImage(bmp, new Point(10, 130));

}

Answer 1

您的代码中存在错误，您忘记初始化位图。它将填充 Color.Transparent、黑色、alpha 为 0 的像素。当您绘制文本时，Graphics.DrawString() 将实现您要求的 TextRenderingHint，对文本进行抗锯齿处理。但是文本的前景色是黑色的。并且背景颜色是黑色。所以抗锯齿像素从黑色混合到黑色。完全破坏了抗锯齿效果，它将字母形状变成了一个斑点。修复：

Bitmap bmp = new Bitmap(width, 20);
using (Graphics gfx = Graphics.FromImage(bmp))
{
    gfx.Clear(this.BackColor);
    // etc...
}