WPF實現(xiàn)自繪儀表盤Gauge

更新時間：2024年12月31日 10:12:42 作者：WPF開發(fā)者

這篇文章主要為大家詳細介紹了如何使用WPF實現(xiàn)自繪儀表盤Gauge效果,文中的示例代碼講解詳細,感興趣的小伙伴可以跟隨小編一起學習一下

自繪儀表盤 Gauge

框架支持.NET4 至 .NET8；

Visual Studio 2022;

WPFDevelopers 1.1.0.3-preview 版本已正式發(fā)布！

該版本為預覽版，歡迎各位開發(fā)者下載并體驗。

來自 Issue

邏輯實現(xiàn)

Gauge 繼承 RangeBase，支持設置最大值、最小值以及當前值，并且可以顯示一個動態(tài)的百分比值、標題、刻度。

1. 新增 Gauge.cs

依賴屬性

Title：儀表盤的標題，默認值為 "WD"。
ValueFormat：定義數(shù)值顯示的格式（ {0:0}%），以百分比形式顯示當前值。
Thickness：設置儀表盤的邊框，默認值 10。

public string Title
{
    get { return (string)GetValue(TitleProperty); }
    set { SetValue(TitleProperty, value); }
}
 public string ValueFormat
 {
     get { return (string)GetValue(ValueFormatProperty); }
     set { SetValue(ValueFormatProperty, value); }
 }
 public double Thickness
 {
     get { return (double)GetValue(ThicknessProperty); }
     set { SetValue(ThicknessProperty, value); }
 }

RangeBase 依賴屬性

Value：設置為 0.0，表示當前的儀表盤值（默認 0%）。
Minimum：設置為 0.0，表示儀表盤的最小值。
Maximum：設置為 100.0，表示儀表盤的最大值。

public Gauge()
{
    SetValue(ValueProperty, 0.0);
    SetValue(MinimumProperty, 0.0);
    SetValue(MaximumProperty, 100.0);
}

2. 重寫 OnRender 方法繪制控件

背景：使用 Ellipse 作為儀表盤的背景，背景色通過 Background 屬性設置，默認為 #293950。

指針：根據(jù)當前值（Value），計算出指針的角度，并使用 DrawLine 繪制紅色指針。

外邊框：使用漸變顏色繪制儀表盤的外邊框。

刻度和標簽：繪制了從最小值到最大值的刻度線，并在每個刻度繪制了對應的刻度值。

當前值顯示：根據(jù) ValueFormat 屬性格式化顯示當前值，并顯示在儀表盤的底部位置。

protected override void OnRender(DrawingContext drawingContext)
{
    base.OnRender(drawingContext);
    if (Background == null)
        Background = new SolidColorBrush((Color)ColorConverter.ConvertFromString("#293950"));
    var width = ActualWidth;
    var height = ActualHeight;
    var radius = Math.Min(width, height) / 2;
    drawingContext.DrawEllipse(Background, new Pen(Background, Thickness), new Point(width / 2, height / 2), radius, radius);
    var normalizedValue = (Value - Minimum) / (Maximum - Minimum);
    var mappedAngle = -220 + normalizedValue * 260;
    var angleInRadians = mappedAngle * Math.PI / 180;
    var pointerLength = radius * 0.7;
    var pointerX = width / 2 + pointerLength * Math.Cos(angleInRadians);
    var pointerY = height / 2 + pointerLength * Math.Sin(angleInRadians);
    drawingContext.DrawLine(new Pen(Brushes.Red, 2), new Point(width / 2, height / 2), new Point(pointerX, pointerY));
    drawingContext.DrawEllipse(Brushes.White, new Pen(Brushes.Red, 2), new Point(width / 2, height / 2), width / 20, width / 20);
    var pathGeometry = new PathGeometry();
    var startAngle = -220;
    angleInRadians = startAngle * Math.PI / 180;
    var startX = width / 2 + radius * Math.Cos(angleInRadians);
    var startY = height / 2 + radius * Math.Sin(angleInRadians);

    var pathFigure = new PathFigure()
    {
        StartPoint = new Point(startX, startY),
    };

    var endAngle = 40;
    angleInRadians = endAngle * Math.PI / 180;
    var endX = width / 2 + radius * Math.Cos(angleInRadians);
    var endY = height / 2 + radius * Math.Sin(angleInRadians);

    var isLargeArc = (endAngle - startAngle > 180);
    var arcSegment = new ArcSegment()
    {
        Point = new Point(endX, endY),
        Size = new Size(radius, radius),
        RotationAngle = 0,
        SweepDirection = SweepDirection.Clockwise,
        IsLargeArc = isLargeArc,
    };

    pathFigure.Segments.Add(arcSegment);
    pathGeometry.Figures.Add(pathFigure);
    if (BorderBrush == null)
    {
        var gradientBrush = new LinearGradientBrush
        {
            StartPoint = new Point(0, 0),
            EndPoint = new Point(1, 0)
        };
        gradientBrush.GradientStops.Add(new GradientStop((Color)ColorConverter.ConvertFromString("#37D2C2"), 0.0));
        gradientBrush.GradientStops.Add(new GradientStop((Color)ColorConverter.ConvertFromString("#5AD2B2"), 0.01));
        gradientBrush.GradientStops.Add(new GradientStop((Color)ColorConverter.ConvertFromString("#B77D29"), 0.49));
        gradientBrush.GradientStops.Add(new GradientStop(Colors.Red, 1.0));
        gradientBrush.Freeze();
        BorderBrush = gradientBrush;
    }
    drawingContext.DrawGeometry(null, new Pen(BorderBrush, Thickness), pathGeometry);
    var tickLength = radius * 0.1; 
    var step = (Maximum - Minimum) / 10;
    for (int i = 0; i <= 10; i++)
    {
        var angle = startAngle + (i * (endAngle - startAngle) / 10);
        var tickStartX = width / 2 + (radius - tickLength) * Math.Cos(angle * Math.PI / 180);
        var tickStartY = height / 2 + (radius - tickLength) * Math.Sin(angle * Math.PI / 180);
        var tickEndX = width / 2 + (radius + Thickness / 2) * Math.Cos(angle * Math.PI / 180);
        var tickEndY = height / 2 + (radius + Thickness / 2) * Math.Sin(angle * Math.PI / 180);
        drawingContext.DrawLine(new Pen(Brushes.White, 2), new Point(tickStartX, tickStartY), new Point(tickEndX, tickEndY));

        var labelValue = Minimum + step * i;
        var formattedText = DrawingContextHelper.GetFormattedText(labelValue.ToString(),Brushes.White, FlowDirection.LeftToRight,FontSize);

        var labelRadius = radius - tickLength * 2;
        var labelX = width / 2 + labelRadius * Math.Cos(angle * Math.PI / 180) - formattedText.Width / 2;
        var labelY = height / 2 + labelRadius * Math.Sin(angle * Math.PI / 180) - formattedText.Height / 2;
        drawingContext.DrawText(formattedText, new Point(labelX, labelY));
    }
    var formattedValue = "{0:0}%";
    try
    {
        formattedValue = string.Format(ValueFormat, Value);
    }
    catch (FormatException ex)
    {
        throw new InvalidOperationException("Formatting failed ", ex);
    }
    var currentValueText = DrawingContextHelper.GetFormattedText(formattedValue, Brushes.White, FlowDirection.LeftToRight, FontSize * 2);
    var valueX = width / 2 - currentValueText.Width / 2;
    var valueY = height / 2 + radius * 0.4; 
    drawingContext.DrawText(currentValueText, new Point(valueX, valueY));
    var titleValue = DrawingContextHelper.GetFormattedText(Title, Brushes.White, FlowDirection.LeftToRight, FontSize);
    valueX = width / 2 - titleValue.Width / 2;
    valueY = height / 2 + radius * 0.8;
    drawingContext.DrawText(titleValue, new Point(valueX, valueY));
}

XAML 示例

示例引入 WPFDevelopers 1.1.0.3-preview 的 Nuget 正式包

<WrapPanel HorizontalAlignment="Center" VerticalAlignment="Center">
    <StackPanel VerticalAlignment="Bottom">
        <wd:Gauge
            Title="Min"
            Width="100"
            Height="100"
            Margin="10"
            HorizontalAlignment="Center"
            VerticalAlignment="Center"
            Background="Black"
            BorderBrush="Red"
            FontSize="8"
            Maximum="90"
            Minimum="30"
            Thickness="3"
            ValueFormat="{}{0:0}值"
            Value="{Binding ElementName=MySlider2, Path=Value}" />
        <Slider
            Name="MySlider2"
            Width="200"
            Margin="0,0,0,20"
            HorizontalAlignment="Center"
            VerticalAlignment="Bottom"
            Maximum="90"
            Minimum="30" />
    </StackPanel>

    <StackPanel>
        <wd:Gauge
            Title="反對率"
            Width="200"
            Height="200"
            Margin="10"
            HorizontalAlignment="Center"
            VerticalAlignment="Center"
            ValueFormat="{}{0:0}%"
            Value="{Binding ElementName=MySlider, Path=Value}" />
        <Slider
            Name="MySlider"
            Width="200"
            Margin="0,0,0,20"
            HorizontalAlignment="Center"
            VerticalAlignment="Bottom"
            Maximum="100"
            Minimum="0" />
    </StackPanel>
    <StackPanel VerticalAlignment="Bottom">
        <wd:Gauge
            Title="Max"
            Width="100"
            Height="100"
            Margin="10"
            HorizontalAlignment="Center"
            VerticalAlignment="Center"
            Background="Black"
            BorderBrush="DodgerBlue"
            FontSize="8"
            Maximum="90"
            Minimum="30"
            Thickness="3"
            ValueFormat="{}{0:0}值"
            Value="{Binding ElementName=MySlider3, Path=Value}" />
        <Slider
            Name="MySlider3"
            Width="200"
            Margin="0,0,0,20"
            HorizontalAlignment="Center"
            VerticalAlignment="Bottom"
            Maximum="90"
            Minimum="30" />
    </StackPanel>
</WrapPanel>

效果圖