在位图上绘制矩形 (Mandelbrot)

Question

您好，我接到了将 java 应用程序转换为 c# windows 窗体应用程序的任务。该程序显示一个 Mandelbrot，然后允许用户放大。我已经设法显示 Mandelbrot 甚至缩放。但是，当拖动框进行缩放时，框本身不会显示，这意味着用户无法看到他们将放大到哪个区域。

我认为我需要在拖动时调用绘制矩形的更新函数这是我认为相关的代码。

private void Form1_MouseDown(object sender, MouseEventArgs e)
{
    //e.consume();
    if (action)
    {
        xs = e.X;
        ys = e.Y;
    }
}

private void Form1_MouseUp(object sender, MouseEventArgs e)
{
    int z, w;

    //e.consume();
    if (action)
    {
        xe = e.X;
        ye = e.Y;
        if (xs > xe)
        {
            z = xs;
            xs = xe;
            xe = z;
        }
        if (ys > ye)
        {
            z = ys;
            ys = ye;
            ye = z;
        }
        w = (xe - xs);
        z = (ye - ys);
        if ((w < 2) && (z < 2))
            initvalues();
        else
        {
            if (((float)w > (float)z * xy))
                ye = (int)((float)ys + (float)w / xy);
            else
                xe = (int)((float)xs + (float)z * xy);
            xende = xstart + xzoom * (double)xe;
            yende = ystart + yzoom * (double)ye;
            xstart += xzoom * (double)xs;
            ystart += yzoom * (double)ys;
        }
        xzoom = (xende - xstart) / (double)x1;
        yzoom = (yende - ystart) / (double)y1;
        mandelbrot();
        rectangle = false;

        Refresh();
    }
}

private void Form1_MouseMove(object sender, MouseEventArgs e)
{
    //e.consume();
    if (action)
    {
        xe = e.X;
        ye = e.Y;
        rectangle = true;
    }
}

private void Form1_Paint(object sender, PaintEventArgs e)
{
    Graphics g1 = e.Graphics;
    g1.DrawImage(bitmap, 0, 0, x1, y1);
    g1.Dispose();
}

public void paint(Graphics g1)
{
    update(g1);
}

public void update(Graphics g1)
{
    Pen pen = new Pen(Color.White);
    g1.DrawImage(bitmap, 0, 0, x1, y1);
    if (rectangle)
    {

        if (xs < xe)
        {
            if (ys < ye) g1.DrawRectangle(pen, xs, ys, (xe - xs), (ye - ys));
            else g1.DrawRectangle(pen, xs, ye, (xe - xs), (ys - ye));
        }
        else
        {
            if (ys < ye) g1.DrawRectangle(pen, xe, ys, (xs - xe), (ye - ys));
            else g1.DrawRectangle(pen, xe, ye, (xs - xe), (ys - ye));
        }
        pen.Dispose();

    }
}

Answer 1

您需要在 mousemove 事件处理程序中调用 Form.Update() 或 Form.Refresh()。您还需要在Form1_Paint 事件处理程序中调用绘制矩形函数。然后你就准备好了。