WPF+WriteableBitmap实现高性能曲线图的绘制
作者：流浪g
这篇文章主要为大家详细介绍了如何利用WPF+WriteableBitmap实现高性能曲线图的绘制，文中的示例代码讲解详细，感兴趣的小伙伴可以尝试一下
一、前言
之前分享过一期关于DrawingVisual来绘制高性能曲线的博客，今天再分享一篇通过另一种方式来绘制高性能曲线的方法，也就是通过WriteableBitmap的方式；具体的一些细节这里就不啰嗦了，同样是局部绘制的思想，滚动条拖动到哪里，就只绘制那一部分的曲线，直接贴代码；（该程序在英特尔11代CPU的电脑可能会遇到拖动滚动条曲线图卡住不动的情况，这个是显卡驱动的问题，官方已经修复了，遇到这问题的记得更新一下驱动）
二、正文
1、新建一个类，继承FrameworkElement，然后在里面实现一下绘图的逻辑；
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Text;
using System.IO;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Resources;
using _Font = System.Drawing.Font;
using GDI = System.Drawing;
namespace WriteableBitmapDemo.Controls
{
public class CruveWriteableBitmap : FrameworkElement
{
private static PrivateFontCollection pfc = new PrivateFontCollection();
private WriteableBitmap bitmap;
private int bitmap_width = 0;
private int bitmap_height = 0;
private static _Font font = null;
private static _Font time_font = null;
private PointF[][] horizontals = null;
private PointF[][] horizontals_thin = null;
private PointF[][] verticals = null;
private PointF[][] verticals_thin = null;
private List<PointF> top_points1;
private List<PointF> top_points2;
private List<PointF> top_points3;
private List<PointF> bottom_points;
private List<PointF> labelPosition_up;
private List<string> labelText_up;
private List<PointF> labelPosition_down;
private List<string> labelText_down;
private List<PointF> timePosition;
private List<string> timeText;
private GDI.Pen blackPen = new GDI.Pen(GDI.Color.Black, 1.5f);
private GDI.Pen grayPen = new GDI.Pen(GDI.Color.Gray, 1f);
private GDI.Pen top_pen1 = new GDI.Pen(GDI.Color.Black, 2);
private GDI.Pen top_pen2 = new GDI.Pen(GDI.Color.Orange, 2);
private GDI.Pen top_pen3 = new GDI.Pen(GDI.Color.Purple, 2);public float scaleX { get; set; } = 1f;
private float _ScaleY { get; set; } = 1f;
public float ScaleY
{
get { return _ScaleY; }
set
{
_ScaleY = value;
}
}
static CruveWriteableBitmap()
{
var appRootDataDir = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "msyh.ttf");
if (!File.Exists(appRootDataDir))
{
var key = $"/CurveChartDemo;component/Fonts/msyh.ttf";
StreamResourceInfo info = Application.GetResourceStream(new Uri(key, UriKind.Relative));
using (var stream = info.Stream)
{
byte[] bytes = new byte[stream.Length];
int len = stream.Read(bytes, 0, bytes.Length);
File.WriteAllBytes(appRootDataDir, bytes);
}
}
pfc.AddFontFile(appRootDataDir);
}
public CruveWriteableBitmap()
{
time_font = new _Font(pfc.Families[0], 10);
font = new _Font(pfc.Families[0], 8);
}
public void DrawPoints()
{
//InitBitmap();
if (this.bitmap == null)
{
return;
}
this.bitmap.Lock();
using (Bitmap backBufferBitmap = new Bitmap(this.bitmap_width, this.bitmap_height,
this.bitmap.BackBufferStride, GDI.Imaging.PixelFormat.Format24bppRgb,
this.bitmap.BackBuffer))
{
using (Graphics backBufferGraphics = Graphics.FromImage(backBufferBitmap))
{
backBufferGraphics.SmoothingMode = SmoothingMode.AntiAlias;
backBufferGraphics.CompositingQuality = CompositingQuality.HighSpeed;
backBufferGraphics.Clear(GDI.Color.White);
//粗横线
if (this.horizontals != null)
{
foreach (var horizontal in this.horizontals)
{
backBufferGraphics.DrawLine(blackPen, horizontal[0], horizontal[1]);
}
}
//细横线
if (this.horizontals_thin != null)
{
foreach (var horizontal in this.horizontals_thin)
{
backBufferGraphics.DrawLine(grayPen, horizontal[0], horizontal[1]);
}
}
//粗竖线
if (this.verticals != null)
{
foreach (var vertical in this.verticals)
{
backBufferGraphics.DrawLine(blackPen, vertical[0], vertical[1]);
}
}
//细竖线
if (this.verticals_thin != null)
{
foreach (var vertical in this.verticals_thin)
{
backBufferGraphics.DrawLine(grayPen, vertical[0], vertical[1]);
}
}
//上图曲线1
if (this.top_points1 != null && this.top_points1.Count > 0)
{
backBufferGraphics.DrawLines(top_pen1, top_points1.ToArray());
}
//上图曲线2
if (this.top_points2 != null && this.top_points2.Count > 0)
{
backBufferGraphics.DrawLines(top_pen2, this.top_points2.ToArray());
}
//上图曲线3
if (this.top_points3 != null && this.top_points3.Count > 0)
{
backBufferGraphics.DrawLines(top_pen3, this.top_points3.ToArray());
}
//下图曲线
if (this.bottom_points != null && this.bottom_points.Count > 0)
{
backBufferGraphics.DrawLines(top_pen1, this.bottom_points.ToArray());
}
//文本
if (labelPosition_up != null && labelPosition_up.Count > 0)
{
SizeF fontSize = backBufferGraphics.MeasureString(labelText_up[0], font);
for (int i = 0; i < labelPosition_up.Count; ++i)
{
backBufferGraphics.DrawString(labelText_up[i], font, GDI.Brushes.Black, labelPosition_up[i].X, labelPosition_up[i].Y - fontSize.Height);
}
}
if (labelPosition_down != null && labelPosition_down.Count > 0)
{
for (int i = 0; i < labelPosition_down.Count; ++i)
{
backBufferGraphics.DrawString(labelText_down[i], font, GDI.Brushes.Black, labelPosition_down[i].X, labelPosition_down[i].Y);
}
}
if (timePosition != null && timePosition.Count > 0)
{
for (int i = 0; i < timePosition.Count; ++i)
{
if (i == 0)
backBufferGraphics.DrawString(timeText[i], time_font, GDI.Brushes.Black, timePosition[i].X, timePosition[i].Y);
else
{
SizeF fontSize = backBufferGraphics.MeasureString(timeText[i], time_font);
backBufferGraphics.DrawString(timeText[i], time_font, GDI.Brushes.Black, timePosition[i].X - fontSize.Width / 2, timePosition[i].Y);
}
}
}
backBufferGraphics.Flush();
}
}
this.bitmap.AddDirtyRect(new Int32Rect(0, 0, this.bitmap_width, this.bitmap_height));
this.bitmap.Unlock();
}public void UpdateTimeLabel(List<PointF> timePosition, List<string> timeText)
{
this.timePosition = timePosition;
this.timeText = timeText;
}
public void UpdatePosition(List<PointF> fhr1_points, List<PointF> fhr2_points, List<PointF> fhr3_points, List<PointF> toco_points)
{
this.top_points1 = fhr1_points;
this.top_points2 = fhr2_points;
this.top_points3 = fhr3_points;
this.bottom_points = toco_points;
}
public void UpdateLabelPosition(List<PointF> labelPosition_up, List<string> labelText_up, List<PointF> labelPosition_down, List<string> labelText_down)
{
this.labelPosition_up = labelPosition_up;
this.labelText_up = labelText_up;
this.labelPosition_down = labelPosition_down;
this.labelText_down = labelText_down;
}
public void UpdateHorizontalLine(PointF[][] horizontals, PointF[][] horizontals_thin)
{
this.horizontals = horizontals;
this.horizontals_thin = horizontals_thin;
}
public void UpdateVerticalLine(PointF[][] verticals, PointF[][] verticals_thin)
{
this.verticals = verticals;
this.verticals_thin = verticals_thin;
}
protected override void OnRender(DrawingContext dc)
{
InitBitmap();
if (this.bitmap != null)
{
dc.DrawImage(bitmap, new Rect(0, 0, RenderSize.Width, RenderSize.Height));
}
base.OnRender(dc);
}
private void InitBitmap()
{
if (bitmap == null || this.bitmap.Width != (int)this.ActualWidth || this.bitmap.Height != (int)this.ActualHeight)
{
if ((int)this.ActualWidth > 0 && (int)this.ActualHeight > 0)
{
this.bitmap_width = (int)this.ActualWidth;
this.bitmap_height = (int)this.ActualHeight;
this.bitmap = new WriteableBitmap(bitmap_width, bitmap_height, 96, 96, PixelFormats.Bgr24, null);
this.bitmap.Lock();
using (Bitmap backBufferBitmap = new Bitmap(bitmap_width, bitmap_height,
this.bitmap.BackBufferStride, GDI.Imaging.PixelFormat.Format24bppRgb,
this.bitmap.BackBuffer))
{
using (Graphics backBufferGraphics = Graphics.FromImage(backBufferBitmap))
{
backBufferGraphics.SmoothingMode = SmoothingMode.HighSpeed;
backBufferGraphics.CompositingQuality = CompositingQuality.HighSpeed;
backBufferGraphics.Clear(GDI.Color.White);
backBufferGraphics.Flush();
}
}
this.bitmap.AddDirtyRect(new Int32Rect(0, 0, bitmap_width, bitmap_height));
this.bitmap.Unlock();
}
}
}
}
}2、主窗口添加该控件，并添加滚动条那些
<Window
x:Class="WriteableBitmapDemo.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ct="clr-namespace:WriteableBitmapDemo.Controls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:WriteableBitmapDemo"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
Title="MainWindow"
Width="1500"
Height="450"
Loaded="Window_Loaded"
mc:Ignorable="d">
<Grid>
<ct:CruveWriteableBitmap x:Name="curve" Margin="0,0,0,20" />
<ScrollViewer
Name="scroll"
HorizontalScrollBarVisibility="Auto"
ScrollChanged="ScrollViewer_ScrollChanged"
VerticalScrollBarVisibility="Disabled">
<Canvas x:Name="canvas" Height="1" />
</ScrollViewer>
<Canvas
x:Name="CanvasPanel"
Margin="0,0,0,20"
Background="Transparent" />
</Grid>
</Window>3、主窗口后台添加曲线数值生成方法和更新视图数据方法
using System.Collections.Generic;
using System.Drawing;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
namespace WriteableBitmapDemo
{
/// <summary>
/// MainWindow.xaml 的交互逻辑
/// </summary>
public partial class MainWindow : Window
{
private bool isAdd = true;
private Dictionary<int, int> dicTopPoints = new Dictionary<int, int>();
private Dictionary<int, int> dicBottomPoints = new Dictionary<int, int>();
private float y_scale;
private static int Top_Val_Max = 240;
private static int Top_Val_Min = 30;
private static int Top_X_Sex = 20;
private static int Bottom = 100;
private static int Center = 25;
private static int BottomOffset = 0;
private double offset = -1;
public MainWindow()
{
InitializeComponent();
CanvasPanel.MouseMove += delegate (object sender, MouseEventArgs e)
{
if (e.LeftButton == MouseButtonState.Pressed)
{
if (Mouse.Captured == null) Mouse.Capture(CanvasPanel);
if (offset >= 0 && offset <= CanvasPanel.ActualWidth)
{
scroll.ScrollToHorizontalOffset(scroll.HorizontalOffset - (e.GetPosition(this).X - offset));
}
offset = e.GetPosition(this).X;
}
else
{
offset = -1;
Mouse.Capture(null); // 释放鼠标捕获
}
};
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
//生成曲线数据
int temp = 50;
for (int i = 0; i < 24 * 60 * 60 * 4; i++)
{
if (isAdd)
{
dicTopPoints.Add(i, temp);
temp += 2;
}
else
{
dicTopPoints.Add(i, temp);
temp -= 2;
}
if (temp == 210) isAdd = false;
if (temp == 50) isAdd = true;
}
temp = 0;
for (int i = 0; i < 24 * 60 * 60 * 4; i++)
{
if (isAdd)
{
dicBottomPoints.Add(i, temp);
temp += 2;
}
else
{
dicBottomPoints.Add(i, temp);
temp -= 2;
}
if (temp == 100) isAdd = false;
if (temp == 0) isAdd = true;
}
//初始化滚动条和触发曲线绘制
canvas.Width = dicTopPoints.Count;
scroll.ScrollToLeftEnd();
}
private void ScrollViewer_ScrollChanged(object sender, ScrollChangedEventArgs e)
{
InitChartData((float)scroll.HorizontalOffset);
}
/// <summary>
/// 根据滚动条偏移量更新需要绘制的数据
/// </summary>
/// <param name="offset"></param>
private void InitChartData(float offset)
{
y_scale = (float)((curve.ActualHeight - Center) / (Top_Val_Max - Top_Val_Min + Bottom));
//上图横线
List<PointF[]> horizontalList = new List<PointF[]>();
List<PointF[]> horizontalList_thin = new List<PointF[]>();
for (int y = 0; y <= Top_Val_Max - Top_Val_Min; y += 10)
{
float currentHeight = (float)(curve.ActualHeight - (y + Bottom) * y_scale - Center);
PointF point1 = new PointF(0, currentHeight);
PointF point2 = new PointF((float)curve.ActualWidth, currentHeight);
if (y % 30 == 0)
horizontalList.Add(new PointF[] { point1, point2 });
else
horizontalList_thin.Add(new PointF[] { point1, point2 });
}
for (int y = 0; y <= Bottom; y += 10)
{
float currentHeight = (float)(curve.ActualHeight - y * y_scale - BottomOffset);
PointF point1 = new PointF(0, currentHeight);
PointF point2 = new PointF((float)curve.ActualWidth, currentHeight);
if (y % 20 == 0)
horizontalList.Add(new PointF[] { point1, point2 });
else
horizontalList_thin.Add(new PointF[] { point1, point2 });
}
//竖线与文字
List<PointF[]> verticals = new List<PointF[]>();
List<PointF[]> verticals_thin = new List<PointF[]>();
List<PointF> timePosition = new List<PointF>();
List<string> timeText = new List<string>();
List<PointF> labelPosition_up = new List<PointF>();
List<string> labelText_up = new List<string>();
List<PointF> labelPosition_down = new List<PointF>();
List<string> labelText_down = new List<string>();
for (int i = 0; i < offset + curve.ActualWidth; i += Top_X_Sex * 2)
{
if (i < offset) continue;
//下竖线
PointF point1 = new PointF(i - offset, (float)(curve.ActualHeight - BottomOffset));
PointF point2 = new PointF(i - offset, (float)(curve.ActualHeight - Bottom * y_scale - BottomOffset));
//上竖线
PointF point3 = new PointF(i - offset, 0);
PointF point4 = new PointF(i - offset, (float)(curve.ActualHeight - Bottom * y_scale - Center));
if ((i + (60 * 2)) % (60 * 2) == 0)
{
verticals.Add(new PointF[] { point1, point2 });
verticals.Add(new PointF[] { point3, point4 });
}
else
{
verticals_thin.Add(new PointF[] { point1, point2 });
verticals_thin.Add(new PointF[] { point3, point4 });
}
if (i % 240 == 0)
{
timeText.Add(i + "");
timePosition.Add(new PointF(i - offset, (float)(curve.ActualHeight - Bottom * y_scale - Center)));
}
if ((i + (60 * 2)) % (120 * 2) == 0)
{
for (int y = Top_Val_Min; y <= Top_Val_Max; y += 10)
{
if (y % 30 == 0)
{
labelText_up.Add(y + "");
labelPosition_up.Add(new PointF(i - offset, (float)(curve.ActualHeight - (Bottom + y - Top_Val_Min) * y_scale - Center)));
}
}
for (int y = 20; y <= 100; y += 10)
{
if (y % 20 == 0)
{
labelText_down.Add(y + "");
labelPosition_down.Add(new PointF(i - offset, (float)(curve.ActualHeight - y * y_scale)));
}
}
}
}
List<PointF> top_points1 = new List<PointF>();
for (int i = (int)offset, j = 0; i < dicTopPoints.Count && j < curve.ActualWidth; i++, j++)
{
top_points1.Add(new PointF(j, (float)(curve.ActualHeight - (dicTopPoints[i] + 100 - Top_Val_Min) * y_scale) - Center));
}
List<PointF> top_points2 = new List<PointF>();
for (int i = (int)offset, j = 0; i < dicTopPoints.Count && j < curve.ActualWidth; i++, j++)
{
top_points2.Add(new PointF(j, (float)(curve.ActualHeight - (dicTopPoints[i] + 20 + 100 - Top_Val_Min) * y_scale) - Center));
}
List<PointF> top_points3 = new List<PointF>();
for (int i = (int)offset, j = 0; i < dicTopPoints.Count && j < curve.ActualWidth; i++, j++)
{
top_points3.Add(new PointF(j, (float)(curve.ActualHeight - (dicTopPoints[i] - 20 + 100 - Top_Val_Min) * y_scale) - Center));
}
List<PointF> bottom_points = new List<PointF>();
for (int i = (int)offset, j = 0; i < dicBottomPoints.Count && j < curve.ActualWidth; i++, j++)
{
bottom_points.Add(new PointF(j, (float)(curve.ActualHeight - dicBottomPoints[i] * y_scale - BottomOffset)));
}
curve.UpdateHorizontalLine(horizontalList.ToArray(), horizontalList_thin.ToArray());
curve.UpdateVerticalLine(verticals.ToArray(), verticals_thin.ToArray());
curve.UpdatePosition(top_points1, top_points2, top_points3, bottom_points);
curve.UpdateTimeLabel(timePosition, timeText);
curve.UpdateLabelPosition(labelPosition_up, labelText_up, labelPosition_down, labelText_down);
curve.DrawPoints();
}
}
}三、运行效果
运行效果如下，欢迎各位大佬指点
以上就是WPF+WriteableBitmap实现高性能曲线图的绘制的详细内容，更多关于WPF WriteableBitmap曲线图的资料请关注脚本之家其它相关文章！