20200601小記——C#畫圖（1）

各位大小夥伴，六一快樂！

今天又是煩人的雷雨天，想寫點什麼還真不好想，便總結下C#一些成圖的方法：

在C#中，自帶的畫布本身是一個比較簡單的畫圖工具，直接上代碼：

public class DrawUnint
    {
        Bitmap bitmap;
        Graphics g;
        double dCenterX;
        double dCenterY;
        double scale;
        public void Save_photo(string path)
        {
            //System.IO.File.Delete(path);
            bitmap.Save(path);
            g.Clear(Color.White);
        }
        
        public void Ini(point minLimit, point maxLimit)
        {
            double Xmin = Math.Min(minLimit.x, maxLimit.x);
            double Xmax = Math.Max(minLimit.x, maxLimit.x);
            double Ymin = Math.Min(minLimit.y, maxLimit.y);
            double Ymax = Math.Max(minLimit.y, maxLimit.y);
            dCenterX = (Xmax + Xmin) / 2;
            dCenterY = (Ymax + Ymin) / 2;
            double X_deta = Xmax - Xmin;
            double Y_deta = Ymax - Ymin;
            if (X_deta == 0) X_deta = 100;//X方向只有一個值
            if (Y_deta == 0) Y_deta = 100;//Y方向只有一個值
            int bHeight = 2400;
            scale = bHeight / Y_deta;
            int bWidth = (int)(X_deta * scale);
            //scale = bWidth / X_deta * 0.8;
            //int bHeight = (int)(Y_deta * scale / 0.8);
            bitmap = new Bitmap(bWidth, bHeight);
            g = Graphics.FromImage(bitmap);
            g.FillRectangle(Brushes.White, new Rectangle(0, 0, bWidth, bHeight));
            g.TranslateTransform(bWidth / 2, bHeight / 2);

        }
        public void DrawPoint(PointDraw p, float width = 5)
        {
            g.FillEllipse(p.color, (float)((p.x - dCenterX) * scale), (float)((dCenterY - p.y) * scale), width, width);
        }
        public void DrawPoints(List<point> lp)
        {
            foreach (var p in lp)
            {
                g.FillEllipse(p.color, (float)((p.x - dCenterX) * scale), (float)((dCenterY - p.y) * scale), 8, 8);
            }
        }
        public void DrawPath(PointDraw p1, PointDraw p2, Color color, string pentype = "虛線", float width = 6)
        {
            using (Pen pen = new Pen(color, width))
            {
                //solid 實線
                //Dash 虛線
                if (pentype == "虛線") { pen.DashStyle = System.Drawing.Drawing2D.DashStyle.Dash; }//虛線 
                else { pen.DashStyle = System.Drawing.Drawing2D.DashStyle.Solid; }
                pen.Color = color;
                g.DrawLine(pen, (float)((p1.x - dCenterX) * scale), (float)((dCenterY - p1.y) * scale), (float)((p2.x - dCenterX) * scale), (float)((dCenterY - p2.y) * scale));
            }
        }
        public void DrawCircle(PointDraw circleCenter, double R, double angle_QD, double angle_ZD, Color color, float width = 10)
        {
            Pen pe = new Pen(color, width);
            g.DrawArc(pe, (float)((circleCenter.x - dCenterX) * scale), (float)((dCenterY - circleCenter.y) * scale), 2 * (float)(R * scale), 2 * (float)(R * scale), (float)angle_QD, (float)angle_ZD);

        }
        public void DrawString(string s, Font font, Brush brush, double x, double y, float angle)
        {
            //font = new Font("宋體",20);
            SizeF sizef = g.MeasureString(s, font);
            float dx = (float)((x - dCenterX) * scale);
            float dy = (float)((dCenterY - y) * scale);
            g.TranslateTransform(dx, dy);
            g.RotateTransform(angle);
            g.DrawString(s, font, brush, 0, 0);
            g.RotateTransform(-angle);
            g.TranslateTransform(-dx, -dy);
        }
    }

這裏便涉及到從圖片創建到初始化，以及畫點、畫線、畫圓、寫字等方法的操作再到另存爲圖片，裏頭的屬性也很容易明白，無非是橢圓的長短半軸、線寬、顏色等屬性。這便是C#利用畫布畫圖的方法。

20200601 星期一21:30