c# - 如何用鼠标在现有的pdf中绘制矩形

Question

我不知道我写的是否正确，这是我尝试过的：

private void pdf_Paint(object sender, PaintEventArgs e)
{
    PdfLoadedDocument load = new PdfLoadedDocument(@"C:\Users\Afiqah\Downloads\17DDT17F1016.pdf");
    PdfLoadedPage page = load.Pages[0] as PdfLoadedPage;
    PdfGraphics graphics = page.Graphics;
    graphics.DrawRectangle(pen, rec);
}

private void pdf_MouseDown(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        rec = new Rectangle(e.X, e.Y, 0, 0);
        this.Invalidate();
    }
    if (e.Button == MouseButtons.Right)
    {
        MDown = e.Location;
    }
}

private void pdf_MouseMove(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        rec.Width = e.X - rec.X;
        rec.Height = e.Y - rec.Y;
        this.Invalidate();
    }
    if (e.Button == MouseButtons.Right)
    {
        rec.Location = new Point((e.X - MDown.X) + rec.Left, (e.Y - MDown.Y) + rec.Top);
        MDown = e.Location;
        this.Invalidate();
    }
}

标签： c#