HandyControl/src/Shared/HandyControl_Shared/Controls/Loading/LoadingCircle.cs

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Media;
using System.Windows.Media.Animation;
using HandyControl.Data;


namespace HandyControl.Controls
{
    public class LoadingCircle : LoadingBase
    {
        public static readonly DependencyProperty DotOffSetProperty = DependencyProperty.Register(
            "DotOffSet", typeof(double), typeof(LoadingCircle),
            new FrameworkPropertyMetadata(20.0, FrameworkPropertyMetadataOptions.AffectsRender));

        public double DotOffSet
        {
            get => (double) GetValue(DotOffSetProperty);
            set => SetValue(DotOffSetProperty, value);
        }

        public static readonly DependencyProperty NeedHiddenProperty = DependencyProperty.Register(
            "NeedHidden", typeof(bool), typeof(LoadingCircle),
            new FrameworkPropertyMetadata(ValueBoxes.TrueBox, FrameworkPropertyMetadataOptions.AffectsRender));

        public bool NeedHidden
        {
            get => (bool) GetValue(NeedHiddenProperty);
            set => SetValue(NeedHiddenProperty, ValueBoxes.BooleanBox(value));
        }

        static LoadingCircle()
        {
            DotSpeedProperty.OverrideMetadata(typeof(LoadingCircle),
                new FrameworkPropertyMetadata(6.0, FrameworkPropertyMetadataOptions.AffectsRender));
            DotDelayTimeProperty.OverrideMetadata(typeof(LoadingCircle),
                new FrameworkPropertyMetadata(220.0, FrameworkPropertyMetadataOptions.AffectsRender));
        }

        protected sealed override void UpdateDots()
        {
            var dotCount = DotCount;
            var dotInterval = DotInterval;
            var dotSpeed = DotSpeed;
            var dotDelayTime = DotDelayTime;
            var needHidden = NeedHidden;

            if (dotCount < 1) return;
            PrivateCanvas.Children.Clear();

            //定义动画
            Storyboard = new Storyboard
            {
                RepeatBehavior = RepeatBehavior.Forever
            };

            //创建圆点
            for (var i = 0; i < dotCount; i++)
            {
                var border = CreateBorder(i, dotInterval, needHidden);

                var framesMove = new DoubleAnimationUsingKeyFrames
                {
                    BeginTime = TimeSpan.FromMilliseconds(dotDelayTime * i)
                };

                var subAngle = -dotInterval * i;

                //开始位置
                var frame0 = new LinearDoubleKeyFrame
                {
                    Value = 0 + subAngle,
                    KeyTime = KeyTime.FromTimeSpan(TimeSpan.Zero)
                };

                //开始位置到第一次匀速开始
                var frame1 = new EasingDoubleKeyFrame
                {
                    EasingFunction = new PowerEase
                    {
                        EasingMode = EasingMode.EaseOut
                    },
                    Value = 180 + subAngle,
                    KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(dotSpeed * (0.75 / 7)))
                };

                //第一次匀速开始到第一次匀速结束
                var frame2 = new LinearDoubleKeyFrame
                {
                    Value = 180 + DotOffSet + subAngle,
                    KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(dotSpeed * (2.75 / 7)))
                };

                //第一次匀速结束到匀加速结束
                var frame3 = new EasingDoubleKeyFrame
                {
                    EasingFunction = new PowerEase
                    {
                        EasingMode = EasingMode.EaseIn
                    },
                    Value = 360 + subAngle,
                    KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(dotSpeed * (3.5 / 7)))
                };

                //匀加速结束到匀减速结束
                var frame4 = new EasingDoubleKeyFrame
                {
                    EasingFunction = new PowerEase
                    {
                        EasingMode = EasingMode.EaseOut
                    },
                    Value = 540 + subAngle,
                    KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(dotSpeed * (4.25 / 7)))
                };

                //匀减速结束到第二次匀速结束
                var frame5 = new LinearDoubleKeyFrame
                {
                    Value = 540 + DotOffSet + subAngle,
                    KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(dotSpeed * (6.25 / 7)))
                };

                //第二次匀速结束到匀加速结束
                var frame6 = new EasingDoubleKeyFrame
                {
                    EasingFunction = new PowerEase
                    {
                        EasingMode = EasingMode.EaseIn
                    },
                    Value = 720 + subAngle,
                    KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(dotSpeed))
                };

                framesMove.KeyFrames.Add(frame0);
                framesMove.KeyFrames.Add(frame1);
                framesMove.KeyFrames.Add(frame2);
                framesMove.KeyFrames.Add(frame3);
                framesMove.KeyFrames.Add(frame4);
                framesMove.KeyFrames.Add(frame5);
                framesMove.KeyFrames.Add(frame6);

                Storyboard.SetTarget(framesMove, border);
                Storyboard.SetTargetProperty(framesMove, new PropertyPath("(UIElement.RenderTransform).(TransformGroup.Children)[0].(RotateTransform.Angle)"));
                Storyboard.Children.Add(framesMove);

                if (NeedHidden)
                {
                    //隐藏一段时间
                    var frame7 = new DiscreteObjectKeyFrame
                    {
                        Value = Visibility.Collapsed,
                        KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(dotSpeed))
                    };

                    var frame8 = new DiscreteObjectKeyFrame
                    {
                        Value = Visibility.Collapsed,
                        KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(dotSpeed + 0.4))
                    };

                    var frame9 = new DiscreteObjectKeyFrame
                    {
                        Value = Visibility.Visible,
                        KeyTime = KeyTime.FromTimeSpan(TimeSpan.Zero)
                    };
                    var framesVisibility = new ObjectAnimationUsingKeyFrames
                    {
                        BeginTime = TimeSpan.FromMilliseconds(dotDelayTime * i)
                    };
                    framesVisibility.KeyFrames.Add(frame9);
                    framesVisibility.KeyFrames.Add(frame7);
                    framesVisibility.KeyFrames.Add(frame8);
                    Storyboard.SetTarget(framesVisibility, border);
                    Storyboard.SetTargetProperty(framesVisibility, new PropertyPath("(UIElement.Visibility)"));
                    Storyboard.Children.Add(framesVisibility);
                }
                PrivateCanvas.Children.Add(border);
            }

            Storyboard.Begin();
            if (!IsRunning)
            {
                Storyboard.Pause();
            }
        }

        private Border CreateBorder(int index, double dotInterval, bool needHidden)
        {
            var ellipse = CreateEllipse(index);
            ellipse.HorizontalAlignment = HorizontalAlignment.Center;
            ellipse.VerticalAlignment = VerticalAlignment.Bottom;
            var rt = new RotateTransform
            {
                Angle = -dotInterval * index
            };
            var myTransGroup = new TransformGroup();
            myTransGroup.Children.Add(rt);
            var border = new Border
            {
                RenderTransformOrigin = new Point(0.5, 0.5),
                RenderTransform = myTransGroup,
                Child = ellipse,
                Visibility = needHidden ? Visibility.Collapsed : Visibility.Visible
            };
            border.SetBinding(WidthProperty, new Binding("Width") { Source = this });
            border.SetBinding(HeightProperty, new Binding("Height") { Source = this });

            return border;
        }
    }
}