在位图上画一条线

Question

我在 matlab 中做了一个人脸检测器，我正在将它翻译成 c# 代码，我一切都完成了。我主要使用

 System.Drawing.Bitmap b = new
        System.Drawing.Bitmap("C:*Location of file on computer*");

首先获得图像，在最后的步骤中我有这个代码

public static void ratio(System.Drawing.Bitmap b, Dictionary<int, List<int>> map)
    {
        double height=0;
        double width=0;


        foreach (KeyValuePair<int, List<int>> place in map)
        {
            height = place.Value[2] - place.Value[3];
            width = place.Value[0] - place.Value[1];

            if( ((height/width) >= 1) && ((height/width) <=  2 ) )
                draw(b, place, map);
        }
    }

    public static void draw(System.Drawing.Bitmap bmp, KeyValuePair<int, List<int>> place, Dictionary<int, List<int>> map)
    {
        // Create pen.
        Pen blackPen = new Pen(Color.Black, 3);
        // Create coordinates of points that define line.

        int x1 = place.Value[1];   //topleft to topright
        int y1 = place.Value[3];
        int x2 = place.Value[0];
        int y2 = place.Value[3];

        int x3 = place.Value[0];   //topright to bottomright
        int y3 = place.Value[3];
        int x4 = place.Value[0];
        int y4 = place.Value[2];

        int x5 = place.Value[0];   //bottomright to bottomleft
        int y5 = place.Value[2];
        int x6 = place.Value[1];
        int y6 = place.Value[2];

        int x7 = place.Value[1];   //bottomleft to topleft
        int y7 = place.Value[2];
        int x8 = place.Value[1];
        int y8 = place.Value[3];

        // Draw line to screen.
        using (var graphics = Graphics.FromImage(bmp))
        {
            graphics.DrawLine(blackPen, x1, y1, x2, y2);
        }

        using (var graphics = Graphics.FromImage(bmp))
        {
            graphics.DrawLine(blackPen, x3, y3, x4, y4);
        }

        using (var graphics = Graphics.FromImage(bmp))
        {
            graphics.DrawLine(blackPen, x5, y5, x6, y6);
        }

        using (var graphics = Graphics.FromImage(bmp))
        {
            graphics.DrawLine(blackPen, x7, y7, x8, y8);
        }

    }

在脸部周围绘制一个框。比率使用从连接组件标签获得的标签的边界来找到人脸的正确比率（我的数字只是编出来的）地图是包含标签编号的字典，以及 xmax、xmin、ymax 和 ymin 作为值.一切编译都没有错误，但是，我现在要做的是在脸部周围显示带有绘制框的所述图像，我不确定该怎么做

Answer 1

假设这是一个 Windows.Forms 应用程序，您只需将 PictureBox 控件从工具箱拖放到窗体上，将其 Dock 属性设置为 Fill，然后在代码中设置其 Image 属性：

PictureBox1.Image = b;

Answer 2

在表单设计器中，在表单上放置一个PictureBox 控件，然后按您喜欢的方式定位和调整大小。如果您愿意（或有必要），您可以通过编程方式添加一个。

然后，为表单的Load 事件添加一个事件处理程序，并在该方法中应用以下代码：

System.Drawing.Bitmap b = new System.Drawing.Bitmap("C:*Location of file on computer*");
pictureBox1.Image = b;

那么，你的绘图方法可以变成：

public static void draw(KeyValuePair<int, List<int>> place, Dictionary<int, List<int>> map)
{
    // Create pen.
    Pen blackPen = new Pen(Color.Black, 3);

    // Create coordinates of points that define line.
    int x1 = place.Value[1];   //topleft to topright
    int y1 = place.Value[3];
    int x2 = place.Value[0];
    int y2 = place.Value[3];

    int x3 = place.Value[0];   //topright to bottomright
    int y3 = place.Value[3];
    int x4 = place.Value[0];
    int y4 = place.Value[2];

    int x5 = place.Value[0];   //bottomright to bottomleft
    int y5 = place.Value[2];
    int x6 = place.Value[1];
    int y6 = place.Value[2];

    int x7 = place.Value[1];   //bottomleft to topleft
    int y7 = place.Value[2];
    int x8 = place.Value[1];
    int y8 = place.Value[3];

    // Draw line to screen.
    using (Graphics g = Graphics.FromHwnd(pictureBox1.Handle))
    {
        g.DrawLine(blackPen, x1, y1, x2, y2);
        g.DrawLine(blackPen, x3, y3, x4, y4);
        g.DrawLine(blackPen, x5, y5, x6, y6);
        g.DrawLine(blackPen, x7, y7, x8, y8);
    }

    pictureBox1.Invalidate();
}