C# WPF 用代码画一幅图(*精品*)

概述

     有时候我们的程序界面中需要显示一些简单的示意图,一般我们有原图的话直接嵌入我们程序就可以,但有时候我们没有原图,这时候我们不妨用代码自己画出来.

今天小编要给大家展示的是这样一副图片:

C# WPF 用代码画一幅图(*精品*)_第1张图片

接下来,我就用代码纯手动给画出来。

绘制说明

    ①  首先绘制一个圆:

var elip = new Ellipse();
                elip.Height = d;
                elip.Width = d;
                elip.Stroke = stroke;
                elip.StrokeThickness = 1;


                Canvas.SetTop(elip, marge);
                Canvas.SetLeft(elip, marge);
                this.canvas.Children.Add(elip);

这里Stroke拥戴设置线的颜色,StrokeThickness设置线宽,Height 圆的高度,Width设置宽度,SetTop用来设置圆相对于画布的顶部距离,SetLeft用来设置圆相对于画布左边的距离, this.canvas.Children.Add(elip)用来把创建的控件添加到画布中.

但是我们今天要画的是一个带缺口的圆,那这个就不能满足要求了,那看第二步;

②画一个缺口圆:

var a1 = 95 * Math.PI / 180;
                var a2 = 445 * Math.PI / 180;
                var r = d / 2;


                double startX = r + Math.Cos(a1) * r;
                double startY = r + Math.Sin(a1) * r;
                double endX = r + Math.Cos(a2) * r;
                double endY = r + Math.Sin(a2) * r;
                bool largeArc = Math.Abs(a2 - a1) >= Math.PI;//角度之间的差异和PI比较
                bool sweep = (a1 < a2);//角度比较


                string path = String.Format(System.Globalization.CultureInfo.InvariantCulture,
                     "M {0},{1} A {2},{3} 0 {4} {5} {6},{7}", startX, startY, r, r,
                     largeArc ? 1 : 0, sweep ? 1 : 0, endX, endY);
                var pathe = uIElement as Path;
                var converter = TypeDescriptor.GetConverter(typeof(Geometry));
                pathe.Data = (Geometry)(converter.ConvertFrom(path));
                pathe.Stroke = Brushes.Black;//颜色
                pathe.StrokeThickness = 1;//线粗
                pathe.Width = d+20;
                pathe.Height = d+20;
                pathe.SetTop(marge);
                pathe.SetLeft(marge);
                this.canvas.Children.Add(pathe);

这里圆角度是顺时针的,和我示意图的角度反向正好相反,r是圆的半径,a1是起始弧度,a2是终止弧度,然后计算出来起止点和终止点以后,构建path,注意path是不可以直接给path.Data的,需要转化一下。这样缺口圆就画好了.

③绘制带箭头的线:

首先绘制直线:主要就是new一个实例,设置起始和终止点,线型线宽等

var line = uIElement as Line;
                line.X1 = p1.X;
                line.Y1 = p1.Y;
                line.X2 = p2.X;
                line.Y2 = p2.Y;
                line.Stroke = stroke;
                line.StrokeThickness = strokeThickness;
                this.canvas.Children.Add(line);

前头,主要也是计算起始和终止点:

public Point ArrowPosition(Point p1, Point p2, PositionType positionType)
        {
            var headlen = 5;//箭头线的长度
            var theta = 45;//先头衔与直线的夹角,45°
            var angle = Math.Atan2(p1.Y - p2.Y, p1.X - p2.X) * 180 / Math.PI;
            double angle1 = 0;
            if (positionType == PositionType.StartPoint)
            {
                angle1 = (angle + theta) * Math.PI / 180;
            }
            else
            {
                angle1 = (angle - theta) * Math.PI / 180;
            }
            var x = headlen * Math.Cos(angle1);
            var y = headlen * Math.Sin(angle1);
            var point = new Point(x, y);
            return point;
        }

④绘制字符串:

//绘制字符串
            lable = new Label();
            lable.Content = "270°";
            
                label.Foreground = stroke;
                label.SetTop(p2.Y - marge * 1.2);
                label.SetLeft(p2.X + marge * 1.5);
                this.canvas.Children.Add(label);

这里采用了标签的settop和setleft和① Canvas.SetTop\  Canvas.SetLeft意义一样.

⑤控件加载:

以上我们都把绘制好的控件添加到了canvas中,但是在VM中,canvas需要在界面加载时候获取一下:

protected override void OnViewAttached(object view, object context)
        {
            base.OnViewAttached(view, context);
            var element = view as FrameworkElement;
            if (element == null)
            {
                return;
            }
            canvas = element.FindName("canvas") as Canvas;
        }

这里是通过CM框架的 protected virtual void OnViewAttached(object view, object context);实现的

C# WPF 用代码画一幅图(*精品*)_第2张图片

除此之外我们也可以在Canvas_Loaded事件中获取

public void Canvas_Loaded(object sender, RoutedEventArgs e)
        {
            this.Canvas = sender as Canvas;
            }

前台需要绑定事件:

这里记得引用名称空间:

xmlns:cal="http://www.caliburnproject.org"

以上,如有疑问或者获取源码,请添加小编微信sf-1738658853,加入组织,请备注:进群!

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