如何应用图形缩放并转换为TextRenderer

Question

我在绘制自定义控件时使用缩放和转换我的图形对象,以便应用缩放和滚动.我使用以下内容:

            Matrix mx = new Matrix();
            mx.Scale(mZoomFactor, mZoomFactor);
            mx.Translate(-clip.X + mGraphicsOffsetx, -clip.Y + mGraphicsOffsety);

            e.Graphics.Clip = new Region(this.Bounds);
            e.Graphics.Transform = mx;

然后,当我使用以下方法绘制字符串

Graphics g = ...
g.DrawString(...)

scalling和transforming正确应用于字符串,它们被缩小和缩小等等.

但是,如果我使用以下内容来绘制我的字符串:

TextRenderer.DrawText(...)

文本未正确缩放和转换.

你知道如何将这个概念应用到TextRenderer？

Answer 1

上面的评论是准确的TextRenderer.DrawText- 作为GDI,由于其分辨率依赖性,对坐标转换的支持有限.正如您所注意到的那样,支持坐标转换,但不支持缩放(也不支持坐标旋转).

我们使用的解决方案(以及我能够在互联网上找到的唯一资源)是手动缩放Font和Rectangle对象以反映应用的缩放,Matrix.Scale(float, float)并结合Graphics.Transform:

    private Font GetScaledFont(Graphics g, Font f, float scale)
    {
        return new Font(f.FontFamily,
                        f.SizeInPoints * scale,
                        f.Style,
                        GraphicsUnit.Point,
                        f.GdiCharSet,
                        f.GdiVerticalFont);
    }

    private Rectangle GetScaledRect(Graphics g, Rectangle r, float scale)
    {
        return new Rectangle((int)Math.Ceiling(r.X * scale),
                            (int)Math.Ceiling(r.Y * scale),
                            (int)Math.Ceiling(r.Width * scale),
                            (int)Math.Ceiling(r.Height * scale));
    }

这是整个测试表格:

public partial class Form1 : Form
{
    private PictureBox box = new PictureBox();

    public Form1()
    {
        InitializeComponent();
        this.Load += new EventHandler(Form1_Load);
    }

    public void Form1_Load(object sender, EventArgs e)
    {
        box.Dock = DockStyle.Fill;
        box.BackColor = Color.White;

        box.Paint += new PaintEventHandler(DrawTest);
        this.Controls.Add(box);
    }

    public void DrawTest(object sender, PaintEventArgs e)
    {
        Graphics g = e.Graphics;

        string text = "Test Text";
        float scale = 1.5F;
        float translate = 200F;

        var flags = TextFormatFlags.PreserveGraphicsClipping | TextFormatFlags.PreserveGraphicsTranslateTransform;

        var mx = new Matrix();
        mx.Scale(scale, scale);
        mx.Translate(translate, translate);

        g.Clip = new Region(Bounds);
        g.Transform = mx;

        Size rendererPSize = Bounds.Size;
        Font f = GetScaledFont(g, new Font("Arial", 12), scale);
        Size rendererRSize = TextRenderer.MeasureText(g, text, f, rendererPSize, flags);

        Rectangle rendererRect = new Rectangle(0, 0, rendererRSize.Width, rendererRSize.Height);
        Rectangle r = GetScaledRect(g, rendererRect, scale);

        TextRenderer.DrawText(g, text, f, realRect, Color.Black, flags);
    }

    private Font GetScaledFont(Graphics g, Font f, float scale)
    {
        return new Font(f.FontFamily,
                        f.SizeInPoints * scale,
                        f.Style,
                        GraphicsUnit.Point,
                        f.GdiCharSet,
                        f.GdiVerticalFont);
    }

    private Rectangle GetScaledRect(Graphics g, Rectangle r, float scale)
    {
        return new Rectangle((int)Math.Ceiling(r.X * scale),
                            (int)Math.Ceiling(r.Y * scale),
                            (int)Math.Ceiling(r.Width * scale),
                            (int)Math.Ceiling(r.Height * scale));
    }
}