SkiaSharp 之 WPF 自绘 拖曳小球(案例版)

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所属分类:.NET技术
摘要

感谢各位大佬和粉丝的厚爱和关心( 催更),我会再接再厉的,其实这也是督促自己的一种方式,非常感谢。


感谢各位大佬和粉丝的厚爱和关心( 催更),我会再接再厉的,其实这也是督促自己的一种方式,非常感谢。

刚写了一篇万字长文,自己也休养生息(低调发育)了一段时间,接下来来几个小案例。

拖曳小球

WPF的拖曳效果,基本配置一下,就可以了,但是自绘的话,就得自己控制,按键点击,按键移动和按键松开的事件,与其配合达到目的。

这个效果实现了,其实也变相的实现了WPF里的拖动效果,这个效果用着还是很方便的。

但是代码,确十分的简单。

Wpf 和 SkiaSharp

新建一个WPF项目,然后,Nuget包即可
要添加Nuget包

Install-Package SkiaSharp.Views.WPF -Version 2.88.0 

其中核心逻辑是这部分,会以我设置的60FPS来刷新当前的画板。

skContainer.PaintSurface += SkContainer_PaintSurface; _ = Task.Run(() => {     while (true)     {         try         {             Dispatcher.Invoke(() =>             {                 skContainer.InvalidateVisual();             });             _ = SpinWait.SpinUntil(() => false, 1000 / 60);//每秒60帧         }         catch         {             break;         }     } }); 

实现代码的 鼠标按下,移动,鼠标松开

先对SkiaSharp对象,增加相关事件

    skContainer.MouseDown += SkContainer_MouseDown;     skContainer.MouseUp += SkContainer_MouseUp;     skContainer.MouseMove += SkContainer_MouseMove;    

然后增加相关事件处理代码,我这边都统一处理了.

private void SkContainer_MouseDown(object sender, MouseButtonEventArgs e) {     var cur = e.GetPosition(sender as IInputElement);     drawClock.MouseDown(new SKPoint((float)cur.X, (float)cur.Y), true); } private void SkContainer_MouseUp(object sender, MouseEventArgs e) {     var cur = e.GetPosition(sender as IInputElement);     drawClock.MouseDown(new SKPoint((float)cur.X, (float)cur.Y), false); } private void SkContainer_MouseMove(object sender, MouseEventArgs e) {     var cur = e.GetPosition(sender as IInputElement);     drawClock.MouseMove(new SKPoint((float)cur.X, (float)cur.Y)); } 

拖曳核心类

/// <summary> /// 拖曳  /// </summary> public class Drag {     public SKPoint centerPoint;     public int Radius = 0;     private bool Pressed = false;     private bool CirclePressend = false;     private SKPoint sKPoint = SKPoint.Empty;     private SKPoint CirclePoint = SKPoint.Empty;     private SKCanvas canvas;     private float dx = 0;     private float dy = 0;     /// <summary>     /// 渲染     /// </summary>     public void Render(SKCanvas canvas, SKTypeface Font, int Width, int Height)     {         this.canvas = canvas;         centerPoint = new SKPoint(Width / 2, Height / 2);         this.Radius = 40;         canvas.Clear(SKColors.White);         if (CirclePoint.IsEmpty)         {             CirclePoint = new SKPoint(centerPoint.X, centerPoint.Y);         }         if (CirclePressend)         {             CirclePoint = new SKPoint(sKPoint.X - dx, sKPoint.Y - dy);             DrawCircle(this.canvas, CirclePoint);         }         else         {             DrawCircle(this.canvas, CirclePoint);         }          using var paint = new SKPaint         {             Color = SKColors.Black,             IsAntialias = true,             Typeface = Font,             TextSize = 24         };         var msg = $"X:{ sKPoint.X}  Y:{sKPoint.Y}  Pressed:{Pressed} CirclePressend:{CirclePressend}";         canvas.DrawText(msg, 0, 30, paint);     }     public void MouseMove(SKPoint sKPoint)     {         this.sKPoint = sKPoint;         if (CirclePressend)//按下,就开始拖动         {             CirclePoint = sKPoint;         }     }     public void MouseDown(SKPoint sKPoint, bool Pressed)     {         this.sKPoint = sKPoint;         this.Pressed = Pressed;         if (this.Pressed)         {             this.CirclePressend = CheckPoint(sKPoint, CirclePoint);             if (this.CirclePressend)             {                 dx = sKPoint.X - CirclePoint.X;                 dy = sKPoint.Y - CirclePoint.Y;             }         }         else         {             this.CirclePressend = false;         }     }     public bool CheckPoint(SKPoint sKPoint, SKPoint CirclePoint)     {         var d = Math.Sqrt(Math.Pow(sKPoint.X - CirclePoint.X, 2) + Math.Pow(sKPoint.Y - CirclePoint.Y, 2));         return this.Radius >= d;     }     /// <summary>     /// 画一个圆     /// </summary>     public void DrawCircle(SKCanvas canvas, SKPoint sKPoint)     {         using var paint = new SKPaint         {             Color = SKColors.Blue,             Style = SKPaintStyle.Fill,             IsAntialias = true,             StrokeWidth = 2         };         canvas.DrawCircle(sKPoint.X, sKPoint.Y, Radius, paint);     } } 

效果如下:

SkiaSharp 之 WPF 自绘 拖曳小球(案例版)

我可以点的球的边边哦,这也是一个小技巧,点到球哪里,停止的时候,鼠标还在那个位置,是不是有点像拖动窗体的感觉了。

总结

以前对拖曳总是很好奇,一直想是如何实现的,现在自己也自己从头到尾的实现了,那么,它就是已知的,这就是可以写出来的进步,每天都应该有一点这样的进步。

代码地址

https://github.com/kesshei/WPFSkiaDragDemo.git

https://gitee.com/kesshei/WPFSkiaDragDemo.git

一键三连呦!,感谢大佬的支持,您的支持就是我的动力!

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