如何在C＃中绘制高质量的旋转字符串？

Question

I want to draw a string and rotate it with a custom angle. Simply, I calculate the new dimenstions of the area that contains the rotated image, then create a bitmap object and by means of graphics object of it, I draw a string with 3 transformations (translation to the center, rotation, and reverse translation). I wrote the following code but the quality is not desired. Does anyone have an idea?

    private Image RotateText(string Text, int FontSize, float Angle)
    {

        //Modify angle
        Angle *= -1;

        //Calculate rotation angle in radian
        double AngleInRadian = (Angle * 2 * Math.PI) / 360d;

        //Instantiate a font for text
        Font TextFont = new Font("Tahoma", FontSize, FontStyle.Bold);

        //Measure size of the text
        Graphics Graphic = this.CreateGraphics();
        SizeF TextSize = Graphic.MeasureString(Text, TextFont);

        //Calculate size of the rotated text
        double NewWidth  = Math.Abs(TextSize.Width * Math.Cos(AngleInRadian)) + Math.Abs(TextSize.Height * Math.Sin(AngleInRadian));
        double NewHeight = Math.Abs(TextSize.Width * Math.Sin(AngleInRadian)) + Math.Abs(TextSize.Height * Math.Cos(AngleInRadian));

        //Instantiate a new image for rotated text
        Bitmap RotatedText = new Bitmap((int)(Math.Round(NewWidth)), (int)(Math.Round(NewHeight)));

        //Get graphic object of new isntantiated image for painting
        Graphics TextGraphic = Graphics.FromImage(RotatedText);
        TextGraphic.InterpolationMode = InterpolationMode.High;

        //Calcaute coordination of center of the image
        float OX = (float)NewWidth  / 2f;
        float OY = (float)NewHeight / 2f;

        //Apply transformations (translation, rotation, reverse translation)
        TextGraphic.TranslateTransform(OX, OY);
        TextGraphic.RotateTransform(Angle);
        TextGraphic.TranslateTransform(-OX, -OY);

        //Calculate the loaction of drawing text
        float X = (RotatedText.Width  - TextSize.Width ) / 2f;
        float Y = (RotatedText.Height - TextSize.Height) / 2f;

        //Draw the string
        TextGraphic.DrawString(Text, TextFont, Brushes.White, X, Y);

        //Return the image of rotated text
        return RotatedText;

    }

The result is this:

Answer 1

Try setting the TextRenderingHint property of your Graphics object to AntiAlias

http://msdn.microsoft.com/en-us/library/system.drawing.graphics.textrenderinghint.aspx

Answer 2

You can try a few things:

• In your XAML:

  TextOptions.TextFormattingMode="Display" (and other TextOptions attached properties)

• In your C#:

  TextOptions.SetTextFormattingMode(this, TextFormattingMode.Display);

• Take a look at this SO topic