YZWater3/src/YZWater.Avalonia/Controls/GaugeControl.cs

using Avalonia;
using Avalonia.Controls;
using Avalonia.Media;
using System;
using System.Globalization;

namespace YZWater.Avalonia.Controls;

public class GaugeControl : Control
{
    public static readonly StyledProperty<double> ValueProperty = AvaloniaProperty.Register<GaugeControl, double>(nameof(Value), 0.0);
    public static readonly StyledProperty<double> MinValueProperty = AvaloniaProperty.Register<GaugeControl, double>(nameof(MinValue), 0.0);
    public static readonly StyledProperty<double> MaxValueProperty = AvaloniaProperty.Register<GaugeControl, double>(nameof(MaxValue), 100.0);
    public static readonly StyledProperty<string> TitleProperty = AvaloniaProperty.Register<GaugeControl, string>(nameof(Title), "Flow");
    public static readonly StyledProperty<string> UnitProperty = AvaloniaProperty.Register<GaugeControl, string>(nameof(Unit), "m³/h");
    public static readonly StyledProperty<IBrush> ValueColorProperty = AvaloniaProperty.Register<GaugeControl, IBrush>(nameof(ValueColor));

    public double Value { get => GetValue(ValueProperty); set => SetValue(ValueProperty, value); }
    public double MinValue { get => GetValue(MinValueProperty); set => SetValue(MinValueProperty, value); }
    public double MaxValue { get => GetValue(MaxValueProperty); set => SetValue(MaxValueProperty, value); }
    public string Title { get => GetValue(TitleProperty); set => SetValue(TitleProperty, value); }
    public string Unit { get => GetValue(UnitProperty); set => SetValue(UnitProperty, value); }
    public IBrush ValueColor { get => GetValue(ValueColorProperty); set => SetValue(ValueColorProperty, value); }

    static GaugeControl() { AffectsRender<GaugeControl>(ValueProperty, MinValueProperty, MaxValueProperty, TitleProperty, UnitProperty, ValueColorProperty); }

    protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e) { base.OnAttachedToVisualTree(e); ThemeHelper.ThemeChanged += OnThemeChanged; }
    protected override void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e) { ThemeHelper.ThemeChanged -= OnThemeChanged; base.OnDetachedFromVisualTree(e); }
    private void OnThemeChanged() => InvalidateVisual();

    public override void Render(DrawingContext context)
    {
        base.Render(context);
        var bounds = new Rect(Bounds.Size);
        var cx = bounds.Width / 2; var cy = bounds.Height / 2 + 10;
        var radius = Math.Min(bounds.Width, bounds.Height) / 2 - 20;
        var typeface = new Typeface("Microsoft YaHei", FontStyle.Normal, FontWeight.Bold);

        context.DrawEllipse(ThemeHelper.PanelBg, null, new Rect(cx - radius - 5, cy - radius - 5, (radius + 5) * 2, (radius + 5) * 2));
        DrawArc(context, new Pen(ThemeHelper.Border, 8), cx, cy, radius, 135, 270);

        var normalized = Math.Max(0, Math.Min(1, (Value - MinValue) / (MaxValue - MinValue)));
        var valueAngle = 135 + normalized * 270;
        var valueColor = ValueColor ?? ThemeHelper.Success;
        DrawArc(context, new Pen(valueColor, 8), cx, cy, radius, 135, valueAngle - 135);

        for (int i = 0; i <= 10; i++)
        {
            var angle = 135 + (270.0 * i / 10);
            var rad = angle * Math.PI / 180;
            var isMajor = i % 5 == 0;
            var tickLen = isMajor ? 12 : 6;
            context.DrawLine(new Pen(isMajor ? ThemeHelper.TextPrimary : ThemeHelper.TextDisabled, isMajor ? 2 : 1),
                new Point(cx + Math.Cos(rad) * (radius - tickLen), cy + Math.Sin(rad) * (radius - tickLen)),
                new Point(cx + Math.Cos(rad) * radius, cy + Math.Sin(rad) * radius));
        }

        var pAngle = valueAngle * Math.PI / 180;
        var pLen = radius * 0.7;
        context.DrawLine(new Pen(valueColor, 3), new Point(cx, cy), new Point(cx + Math.Cos(pAngle) * pLen, cy + Math.Sin(pAngle) * pLen));
        context.DrawEllipse(valueColor, null, new Rect(cx - 6, cy - 6, 12, 12));

        var titleText = new FormattedText(Title, CultureInfo.CurrentCulture, FlowDirection.LeftToRight, typeface, 12, ThemeHelper.TextPrimary);
        context.DrawText(titleText, new Point(cx - titleText.Width / 2, bounds.Y + 5));

        var valText = new FormattedText($"{Value:F1}", CultureInfo.CurrentCulture, FlowDirection.LeftToRight, new Typeface("Microsoft YaHei", FontStyle.Normal, FontWeight.Bold), 20, ThemeHelper.TextPrimary);
        context.DrawText(valText, new Point(cx - valText.Width / 2, cy + radius * 0.3));

        var unitText = new FormattedText(Unit, CultureInfo.CurrentCulture, FlowDirection.LeftToRight, new Typeface("Microsoft YaHei"), 10, ThemeHelper.TextDisabled);
        context.DrawText(unitText, new Point(cx - unitText.Width / 2, cy + radius * 0.3 + valText.Height + 2));
    }

    private void DrawArc(DrawingContext context, IPen pen, double cx, double cy, double radius, double startAngle, double sweepAngle)
    {
        var startRad = startAngle * Math.PI / 180;
        var endRad = (startAngle + sweepAngle) * Math.PI / 180;
        var steps = 36;
        var px = cx + Math.Cos(startRad) * radius;
        var py = cy + Math.Sin(startRad) * radius;
        for (int i = 1; i <= steps; i++)
        {
            var t = (double)i / steps;
            var angle = startRad + (endRad - startRad) * t;
            var x = cx + Math.Cos(angle) * radius;
            var y = cy + Math.Sin(angle) * radius;
            context.DrawLine(pen, new Point(px, py), new Point(x, y));
            px = x; py = y;
        }
    }

    protected override Size MeasureOverride(Size availableSize) => new Size(120, 140);
}