将非常高质量的文本呈现为位图

Question

我想在图片上添加一些文字。这是我的方法：

private Bitmap ConvertTextToImage(string text, FontFamily fontFamily, float fontSize, FontStyle fontStyle = FontStyle.Regular,
    StringFormat stringFormat = default, float MaxWidth = float.MaxValue, float MaxHeight = float.MaxValue, Color backgroundColor = default, Color foregroundColor = default)
{
    Bitmap bitmap = new Bitmap(1, 1);
    Graphics graphics = Graphics.FromImage(bitmap);
    if (stringFormat == default) stringFormat = new StringFormat();
    if (backgroundColor == default) backgroundColor = Color.Transparent;
    if (foregroundColor == default) foregroundColor = Color.Black;

    Font font = new Font(fontFamily, fontSize, fontStyle);

    SizeF stringSize = graphics.MeasureString(text, font, int.MaxValue, stringFormat);
    while (stringSize.Width > MaxWidth || stringSize.Height > MaxHeight)
    {
        fontSize -= (float)0.1;
        font = new Font(fontFamily, fontSize, fontStyle);
        stringSize = graphics.MeasureString(text, font, int.MaxValue, stringFormat);
    }
    
    bitmap = new Bitmap((int)stringSize.Width, (int)stringSize.Height);
    graphics = Graphics.FromImage(bitmap);
    graphics.CompositingQuality = CompositingQuality.HighQuality;
    graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
    graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
    graphics.SmoothingMode = SmoothingMode.HighQuality;
    graphics.TextRenderingHint = TextRenderingHint.AntiAliasGridFit;
    graphics.Clear(backgroundColor);
    
    int x = 0;
    if (stringFormat.FormatFlags == StringFormatFlags.DirectionRightToLeft && stringFormat.Alignment == StringAlignment.Center)
        x = (int)stringSize.Width / 2;
    else if (stringFormat.FormatFlags == StringFormatFlags.DirectionRightToLeft) x = (int)stringSize.Width;
    else if (stringFormat.Alignment == StringAlignment.Center) x += (int)stringSize.Width / 2;
    
    graphics.DrawString(text, font, new SolidBrush(foregroundColor), x, 0, stringFormat);
    return bitmap;
}
//...

适用于大字体或简单字体（例如 Samim）。但是对于小尺寸的复杂字体（IranNastaliq），它会变成这样（棕色在主图像上，黑色由 C# 生成）：

所以我决定使用 GraphicsPath.AddString 而不是 Graphics.DrawString:

GraphicsPath graphicsPath = new GraphicsPath();
//...
graphicsPath.AddString(text, fontFamily, (int)fontStyle, fontSize * graphics.DpiY / 72, new Point(x, 0), stringFormat);
graphics.FillPath(new SolidBrush(foregroundColor), graphicsPath);

但是结果还是不好：

如何呈现更高质量的文本？图片分辨率为2480x3508x300dpi，字体大小约为13.

Answer 1

感谢TaW的评论，问题解决了。我应该调整位图分辨率 (DPI) 以匹配原始图片的分辨率。这是正确的代码：

private Bitmap ConvertTextToImage(string text, FontFamily fontFamily, float fontSize,
    FontStyle fontStyle = FontStyle.Regular, StringFormat stringFormat = default,
    float MaxWidth = float.MaxValue, float MaxHeight = float.MaxValue, float xDpi = 72, float yDpi = 72,
    Color backgroundColor = default, Color foregroundColor = default)
{
    //...
    graphics.TextRenderingHint = TextRenderingHint.AntiAliasGridFit;
    bitmap.SetResolution(xDpi,yDpi);
    //...
    graphics.DrawString(text, font, new SolidBrush(foregroundColor), x, 0, stringFormat);
}

private void Write()
{
    //...
    Bitmap name = ConvertTextToImage(Name.Text, IranNastaliq, 58, MaxWidth: 525, xDpi: 300, yDpi: 300);
    graphics.DrawImage(name, new Point(1104, 1700));
    //...
    bitmap.Save("img.jpg", ImageFormat.Jpeg);
}

结果（黑色文字由GDI绘制）：

将非常高质量的文本呈现为位图

render very high quality text to bitmap

c#

render

bitmap