Question

我正在试图将多边形列表绘制到图像框中。目前我只得到了屏幕左上角的对角黑线。这些点如下:

20,20 0,20 20,0 40,40

200,100 0,20 20,0 20,20

100, 200 0, 200 200,0 250, 450

150,130 1,20 20,0 10,20

    private void pictureBox1_Paint_1(object sender, PaintEventArgs e)
    {
        int jobIndex = 0;
        int trussIndex = 0;

        Graphics g = e.Graphics;
        foreach (Member m in jobArray[jobIndex].trusses[trussIndex].members)
        {
            Point[] pointArray = new Point[m.poly.Points.Count()];
            //m.poly.Points.CopyTo(pointArray, 0);
            int index =0;
            foreach(System.Windows.Point p in m.poly.Points)
            {
                pointArray[index].X = (int)p.X;
                pointArray[index].Y = (int)p.Y;
                index++;
            }
            Pen myPen = new Pen(Color.Black);
            SolidBrush myBrush = new SolidBrush(m.color);

            g.DrawPolygon(myPen, pointArray);
            g.FillPolygon(myBrush, pointArray);

        }
    }

Any Ideas as to why the polygons do not appear on the imagebox? The colors are no the issue nor the size of the box

Answer 1

似乎您使用“ 绘画事件” 来调用这个方法, 确保您在调用该方法时拥有可用的数据。油漆事件不总是被调用, 所以如果您要添加数据来绘制的话, 您需要调用“ 图片Box1. Invalifate () ” 的方法来强制绘制事件。

我敢肯定,你迟早会看到这一点,但你应该创建一个图像(Bitmap)对象,并将其指定给 PhotoBox 的图像属性。然后使用图形。从图像(_image) 获得您的图形对象。如果您不这样做,那么如果窗口被覆盖,您的图像将不再停留,然后返回焦点,或者将其拖离屏幕,然后将它拖离屏幕。

private Bitmap _bitMap;
private Graphics _graphic;
Pen myPen;

public Constructor()
{
    _bitMap = new Bitmap(pictureBox1.Width,pictureBox1.Height);
    _graphic = Graphics.FromImage(_bitMap);
    pictureBox1.Image = _bitMap;
    myPen = new Pen(Color.Black);
}
private void DataAdded()
{
    int jobIndex = 0;
    int trussIndex = 0;

    foreach (Member m in jobArray[jobIndex].trusses[trussIndex].members)
    {
        //Pen myPen = new Pen(Color.Black); //Don t instantiate in a loop
        SolidBrush myBrush = new SolidBrush(m.color);
        _graphic.DrawPolygon(myPen, m.poly.Points.ToArray());
        _graphic.FillPolygon(myBrush, m.poly.Points.ToArray());
    }
    pictureBox1.Image = _bitMap; //Don t think you need this, but I don t remember
}

希望这有帮助

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