参考资料：
https://www.jianshu.com/p/d308641498aa
https://zhuanlan.zhihu.com/p/37167062
这是一个来自很久以前的代码
通过DrawingVisual和DispatchFrame快速提升绘图速度
代码里有两种，一种是组合线形成矩形，另外一种是直接生成矩形，两者不同就是是否可以精确控制某个矩形。
第一种形成的矩形会比第二多很多，也不会卡。如果某些绘图，单一颜色，效果会很好。
也可以通过变换矩形块在设置颜色也会有很多造型，或者重新编写图形。
截图2
最主要的是继承DrawingVisual和修改canvas。
public class BaseCanvas : Canvas
{
public ObservableCollection<BaseDrawVisual> Visuals
{
get;
private set;
}
ScaleTransform Scale;
public BaseCanvas()
{
Visuals = new ObservableCollection<BaseDrawVisual>();
Scale = new ScaleTransform();
this.RenderTransform = Scale;
}
double sc = 1;
protected override void onm ouseWheel(MouseWheelEventArgs e)
{
// base.OnMouseWheel(e);
if(e.Delta>0)
{
sc += 0.5;
}
else
{
sc -= 0.5;
}
if (sc > 48)
sc = 48;
if (sc < 0.5)
sc = 0.5;
Scale.CenterX = 0;
Scale.CenterY = 0;
Scale.ScaleX = sc;
Scale.ScaleY = sc;
Console.WriteLine("sc:"+sc);
// base.OnMouseWheel(e);
}
protected override Visual GetVisualChild(int index)
{
return Visuals[index];
}
protected override int VisualChildrenCount => Visuals.Count;
public void AddVisual(BaseDrawVisual drawVisual)
{
Visuals.Add(drawVisual);
AddVisualChild(drawVisual);
AddLogicalChild(drawVisual);
}
public void DelAllVisual()
{
foreach (var item in Visuals)
{
RemoveVisualChild(item);
RemoveLogicalChild(item);
}
Visuals.Clear();
}
}
部分元素
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Media;
namespace DrawCanvas
{
public class RectByLineDrawVisual : BaseDrawVisual //也可以直接继承DrawingVisual
{
public RectByLineDrawVisual()
{
}
public RectByLineDrawVisual(double X, double Y, double width, double height, double rectW, double rectH)
{
this.LocationX = X;
this.LocationY = Y;
this.DrawWidth = width;
this.DrawHeight = height;
this.RectWidth = rectW;
this.RectHeight = rectH;
MaxItems = (int)(DrawHeight / RectHeight * DrawWidth / RectWidth);
SelectItem = new List<int[]>();
}
public double DrawHeight { get; set; }
public double DrawWidth { get; set; }
public double RectHeight { get; set; }
public double RectWidth { get; set; }
public double LocationX { get; set; }
public double LocationY { get; set; }
public Pen DrawPen = DrawSetting.Instance.DrawPen;
public override void Draw()
{
DrawPen.Freeze();
using (var BaseDrawing = this.RenderOpen())
{
GeometryGroup gp = new GeometryGroup();
gp.Children.Add(new RectangleGeometry(new Rect(LocationX, LocationY, DrawWidth, DrawHeight)));
for (double x = LocationX; x < LocationX + DrawWidth; x += RectWidth)
{
gp.Children.Add(
new LineGeometry(new Point(x, LocationY), new Point(x, LocationY+DrawHeight)));
}
for (double y = LocationY; y < LocationY + DrawHeight; y += RectHeight)
{
gp.Children.Add(
new LineGeometry(new Point(LocationX, y), new Point(LocationX+DrawWidth, y)));
}
BaseDrawing.DrawDrawing(new GeometryDrawing(DrawColor, DrawPen, gp));
}
}
}
}
主界面cs
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
// Draw();
e.Handled = true;
}
Random GetRandom = new Random();
int k = 0;
private void Draw()
{
draw.DelAllVisual();
for (double i = 0; i < draw.ActualWidth; i +=100)
{
for (double j = 0; j < draw.ActualHeight; j += 100)
{
//NormColor=new SolidColorBrush(Color.FromRgb((byte)GetRandom.Next(1,255), (byte)GetRandom.Next(1, 255), (byte)GetRandom.Next(1, 255)))
//draw.AddVisual(new RectByLineDrawVisual(i, j, 80, draw.ActualHeight, 5, 5));
draw.AddVisual(new RectDrawVisual(i, j, 100, 100, 4, 4));
}
}
}
private void Window_SizeChanged(object sender, SizeChangedEventArgs e)
{
// Draw();
}
private void ProcessMsgs()
{
DoEvents();
}
public void DoEvents()
{
DispatcherFrame frame = new DispatcherFrame();
Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Background,
new DispatcherOperationCallback(ExitFrames), frame);
Dispatcher.PushFrame(frame);
}
public object ExitFrames(object f)
{
((DispatcherFrame)f).Continue = false;
return null;
}
private void Button_Click(object sender, RoutedEventArgs e)
{
Draw();
for (int i = 0; i < draw.Visuals.Count; i++)
{
draw.Visuals[i].Draw();
if (i % 10 == 0)
ProcessMsgs();
}
// this.IsEnabled = true;
}
DispatcherTimer Timer = new DispatcherTimer();
private void Button_Click_1(object sender, RoutedEventArgs e)
{
if (Timer.IsEnabled)
{
Timer.Stop();
return;
}
Timer.Interval = TimeSpan.FromMilliseconds(50);
Timer.Tick += Timer_Tick;
Timer.Start();
}
private void Timer_Tick(object sender, EventArgs e)
{
Changed1();
//Changed2();
}
void Changed1()
{
for (int i = 0; i < draw.Visuals.Count;)
{
var index = GetRandom.Next(0, draw.Visuals.Count);
var item = draw.Visuals[index] as RectDrawVisual;
// item.SelectItem.Clear();
var k = new[] { GetRandom.Next(0, 20), GetRandom.Next(0, 20) };
if (!item.SelectItem.Contains(k))
item.SelectItem.Add(k);
else
item.SelectItem.Remove(k);
item.SelectItemBackGround = new SolidColorBrush(Colors.Red);//new SolidColorBrush(Color.FromRgb((byte)GetRandom.Next(1, 255), (byte)GetRandom.Next(1, 255), (byte)GetRandom.Next(1, 255)));
item.Draw();
ProcessMsgs();
Console.WriteLine(index);
if (i == draw.Visuals.Count - 1)
{
i = 0;
ProcessMsgs();
continue;
}
else
i++;
}
}
void Changed2()
{
var index = GetRandom.Next(0, draw.Visuals.Count - 1);
var item = draw.Visuals[index];
item.DrawColor = new SolidColorBrush(Color.FromRgb((byte)GetRandom.Next(1, 255), (byte)GetRandom.Next(1, 255), (byte)GetRandom.Next(1, 255)));
item.Draw();
// ProcessMsgs();
}
}