WPF image swipe to change image like in iOS

Can anyone point me to some code samples on how I could implement a gallery like the one in iOS where you can swipe side to side to change the image when using a touchscreen monitor on Windows 7?

标签： c# wpf touchscreen

1条回答

爱情/是我丢掉的垃圾

2楼-- · 2019-04-29 00:57

You will need to implement swipe-like animations for this.

Guidelines for touch in WPF apps

I haven't tried this myself, but here is what seems to be an open source repo for a WPF carousel that might be worth taking a look at

~~Blog entry about swipe animation in WPF~~

Change the image on desired 'swipe-movement' :)

Free animation libraries if you don't want to create the animation yourself

Hope it helps!

Here is (by the way) the carousel control in the second link in case it goes missing like the previous one:

Code by Michael Palotas

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Threading;

namespace WPFDemo
{
    public class CarouselControl : Canvas
    {
        public CarouselControl()
        {
            _timer.Tick += new EventHandler(TimerTick);
            _timer.Interval = TimeSpan.FromMilliseconds(10);
        }

        public DateTime _previousTime;
        public DateTime _currentTime;

        public void ReInitialize()
        {
            Init();
        }

        protected override void OnInitialized(EventArgs e)
        {
            base.OnInitialized(e);
            Init();
        }

        public delegate void OnElementSelectedHandler(object sender);
        public event OnElementSelectedHandler OnElementSelected;

        public void SelectElement(FrameworkElement element)
        {
            if (element != null)
            {
                _previousTime = DateTime.Now;

                RotateToElement(element);

                if (OnElementSelected != null)
                    OnElementSelected(element);
            }
        }

        private const double DEFAULT_ROTATION_SPEED = 200;
        private const double MINIMUM_ROTATION_SPEED = 1;
        private const double MAXIMUM_ROTATION_SPEED = 1000;
        private double _rotationSpeed = DEFAULT_ROTATION_SPEED;
        public double RotationSpeed
        {
            get
            {
                return _rotationSpeed;

            }
            set
            {
                _rotationSpeed = Math.Min(Math.Max(value, MINIMUM_ROTATION_SPEED), MAXIMUM_ROTATION_SPEED);
            }
        }

        private const double DEFAULT_LOOKDOWN_OFFSET = 0;
        private const double MINIMUM_LOOKDOWN_OFFSET = -100;
        private const double MAXIMUM_LOOKDOWN_OFFSET = 100;
        private double _lookdownOffset = DEFAULT_LOOKDOWN_OFFSET;
        public double LookDownOffset
        {
            get
            {
                return _lookdownOffset;

            }
            set
            {
                _lookdownOffset = Math.Min(Math.Max(value, MINIMUM_LOOKDOWN_OFFSET), MAXIMUM_LOOKDOWN_OFFSET);
            }
        }

        private const double DEFAULT_FADE = 0.5;
        private const double MINIMUM_FADE = 0;
        private const double MAXIMUM_FADE = 1;
        private double _fade = DEFAULT_FADE;
        public double Fade
        {
            get
            {
                return _fade;

            }
            set
            {
                _fade = Math.Min(Math.Max(value, MINIMUM_FADE), MAXIMUM_FADE);
            }
        }

        private const double DEFAULT_SCALE = 0.5;
        private const double MINIMUM_SCALE = 0;
        private const double MAXIMUM_SCALE = 1;
        private double _scale = DEFAULT_SCALE;
        public double Scale
        {
            get
            {
                return _scale;

            }
            set
            {
                _scale = Math.Min(Math.Max(value, MINIMUM_SCALE), MAXIMUM_SCALE);
            }
        }

        private void element_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            SelectElement(sender as FrameworkElement);
        }

        private void RotateToElement(FrameworkElement element)
        {
            if (element != _currentlySelected)
            {
                _currentlySelected = element;
                int targetIndex = Children.IndexOf(element);

                double degreesToRotate = GetDegreesNeededToPlaceElementInFront(_currentRotation, targetIndex, TotalNumberOfElements);
                _targetRotation = ClampDegrees(_currentRotation - degreesToRotate);

                StartRotation(degreesToRotate);
            }
        }

        internal static double GetDegreesNeededToPlaceElementInFront(double currentRotation, int targetIndex, int totalNumberOfElements)
        {
            double rawDegrees = -(180.0 - (currentRotation + 360.0 * ((double)targetIndex / (double)totalNumberOfElements)));

            if (rawDegrees > 180)
                return -(360 - rawDegrees);

            return rawDegrees;
        }

        private double RotationAmount
        {
            get
            {
                return (_currentTime - _previousTime).TotalSeconds * _rotationSpeed;
            }
        }


        private const double INTERNAL_SCALE_COEFFICIENT = 0.6;
        private void Init()
        {
            _previousTime = _currentTime = DateTime.Now;

            X_SCALE = CenterX * INTERNAL_SCALE_COEFFICIENT;
            Y_SCALE = CenterY * INTERNAL_SCALE_COEFFICIENT;

            foreach (FrameworkElement element in Children)
            {
                element.MouseLeftButtonDown += new MouseButtonEventHandler(element_MouseLeftButtonDown);
                element.Cursor = Cursors.Hand;
            }

            SelectElement(GetChild(0));

            SetElementPositions();
        }


        private FrameworkElement _currentlySelected = null;
        public FrameworkElement CurrentlySelected { get { return _currentlySelected; } }
        protected double CenterX { get { return this.Width / 2.0; } }
        protected double CenterY { get { return this.Height / 2.0; } }

        protected double X_SCALE = 0;
        protected double Y_SCALE = 0;

        protected DispatcherTimer _timer = new DispatcherTimer();
        private double _rotationToGo = 0;

        private int TotalNumberOfElements { get { return Children.Count; } }
        protected double _currentRotation = 0;

        protected double _targetRotation = 0;


        protected virtual void TimerTick(object sender, EventArgs e)
        {
            _currentTime = DateTime.Now;

            if ((_rotationToGo < RotationAmount) && (_rotationToGo > -RotationAmount))
            {
                _rotationToGo = 0;

                if (_currentRotation != _targetRotation)
                {
                    _currentRotation = _targetRotation;
                }
                else
                {
                    _timer.Stop();
                    return;
                }
            }
            else if (_rotationToGo < 0)
            {
                _rotationToGo += RotationAmount;
                _currentRotation = ClampDegrees(_currentRotation + RotationAmount);
            }
            else
            {
                _rotationToGo -= RotationAmount;
                _currentRotation = ClampDegrees(_currentRotation - RotationAmount);
            }

            SetElementPositions();

            _previousTime = _currentTime;
        }

        protected double ClampDegrees(double rawDegrees)
        {
            if (rawDegrees > 360)
                return rawDegrees - 360;

            if (rawDegrees < 0)
                return rawDegrees + 360;

            return rawDegrees;
        }

        public void SetElementPositions()
        {
            for (int index = 0; index < TotalNumberOfElements; index++)
            {
                FrameworkElement element = GetChild(index);

                double elementWidthCenter = GetElementCenter(element.Width, element.ActualWidth);
                double elementHeightCenter = GetElementCenter(element.Height, element.ActualHeight);

                double degrees = 360 * ((double)index / (double)TotalNumberOfElements) + _currentRotation;

                double x = -X_SCALE * Math.Sin(ConvertToRads(degrees)) - (double.IsNaN(Y_SCALE) ? 0.0 : Y_SCALE / 100.0) * (Math.Cos(ConvertToRads(degrees)) * LookDownOffset);
                Canvas.SetLeft(element, x + CenterX - elementWidthCenter);

                double y = Y_SCALE * Math.Sin(ConvertToRads(degrees)) - (double.IsNaN(X_SCALE) ? 0.0 : X_SCALE / 100.0) * (Math.Cos(ConvertToRads(degrees)) * LookDownOffset);
                Canvas.SetTop(element, y + CenterY - elementHeightCenter);

                ScaleTransform scale = element.RenderTransform as ScaleTransform;
                if (scale == null)
                {
                    scale = new ScaleTransform();
                    element.RenderTransform = scale;
                }

                scale.CenterX = elementWidthCenter;
                scale.CenterY = elementHeightCenter;
                scale.ScaleX = scale.ScaleY = GetScaledSize(degrees);
                Canvas.SetZIndex(element, GetZValue(degrees));

                SetOpacity(element, degrees);
            }
        }

        private FrameworkElement GetChild(int index)
        {
            if (Children.Count == 0)
                return null;

            FrameworkElement element = Children[index] as FrameworkElement;

            if (element == null)
                throw new NotSupportedException("Carousel only supports children that are Framework elements");

            return element;
        }

        internal static double GetElementCenter(double elementDimension, double elementActualDimension)
        {
            return double.IsNaN(elementDimension) ? elementActualDimension / 2.0 : elementDimension / 2.0;
        }


        private void SetOpacity(FrameworkElement element, double degrees)
        {
            element.Opacity = (1.0 - Fade) + Fade * GetCoefficient(degrees);
        }

        private int GetZValue(double degrees)
        {
            return (int)(360 * GetCoefficient(degrees));
        }

        private double GetScaledSize(double degrees)
        {
            return (1.0 - Scale) + Scale * GetCoefficient(degrees);
        }

        private double GetCoefficient(double degrees)
        {
            return 1.0 - Math.Cos(ConvertToRads(degrees)) / 2 - 0.5;
        }

        private double ConvertToRads(double degrees)
        {
            return degrees * Math.PI / 180.0;
        }

        private void StartRotation(double numberOfDegrees)
        {
            _rotationToGo = numberOfDegrees;
            if (!_timer.IsEnabled)
            {
                _timer.Start();
            }
        }
    }
}

XAML:

<UserControl
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
x:Class="WPFDemo.SphereControl"
x:Name="UserControl"
d:DesignWidth="50" d:DesignHeight="50">
<UserControl.Resources>
    <Storyboard x:Key="MouseOver">
        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="LayoutRoot" Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)">
            <SplineDoubleKeyFrame KeyTime="00:00:00" Value="1"/>
            <SplineDoubleKeyFrame KeyTime="00:00:00.1000000" Value="1.3" KeySpline="0,0,0.5,1"/>
        </DoubleAnimationUsingKeyFrames>
        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="LayoutRoot" Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleY)">
            <SplineDoubleKeyFrame KeyTime="00:00:00" Value="1"/>
            <SplineDoubleKeyFrame KeyTime="00:00:00.1000000" Value="1.3" KeySpline="0,0,0.5,1"/>
        </DoubleAnimationUsingKeyFrames>
        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="Ellipse" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[2].(GradientStop.Offset)">
            <SplineDoubleKeyFrame KeyTime="00:00:00" Value="0"/>
            <SplineDoubleKeyFrame KeyTime="00:00:00.1000000" Value="0.231"/>
        </DoubleAnimationUsingKeyFrames>
        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="Ellipse" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Offset)">
            <SplineDoubleKeyFrame KeyTime="00:00:00" Value="0.312"/>
            <SplineDoubleKeyFrame KeyTime="00:00:00.1000000" Value="0.729"/>
        </DoubleAnimationUsingKeyFrames>
    </Storyboard>
    <Storyboard x:Key="MouseLeave">
        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="LayoutRoot" Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)">
            <SplineDoubleKeyFrame KeyTime="00:00:00.5" Value="1" KeySpline="0,0,0.5,1"/>
        </DoubleAnimationUsingKeyFrames>
        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="LayoutRoot" Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleY)">
            <SplineDoubleKeyFrame KeyTime="00:00:00.5" Value="1" KeySpline="0,0,0.5,1"/>
        </DoubleAnimationUsingKeyFrames>
        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="Ellipse" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[2].(GradientStop.Offset)">
            <SplineDoubleKeyFrame KeyTime="00:00:00.5" Value="0"/>
        </DoubleAnimationUsingKeyFrames>
        <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="Ellipse" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Offset)">
            <SplineDoubleKeyFrame KeyTime="00:00:00.5" Value="0.312"/>
        </DoubleAnimationUsingKeyFrames>
    </Storyboard>
</UserControl.Resources>
<UserControl.Triggers>
    <EventTrigger RoutedEvent="Mouse.MouseEnter">
        <BeginStoryboard Storyboard="{StaticResource MouseOver}" x:Name="MouseOver_BeginStoryboard"/>
    </EventTrigger>
    <EventTrigger RoutedEvent="Mouse.MouseLeave">
        <BeginStoryboard Storyboard="{StaticResource MouseLeave}"  x:Name="MouseLeave_BeginStoryboard"/>
    </EventTrigger>
</UserControl.Triggers>

<Grid x:Name="LayoutRoot" RenderTransformOrigin="0.5,0.5">
    <Grid.RenderTransform>
        <TransformGroup>
            <ScaleTransform ScaleX="1" ScaleY="1"/>
            <SkewTransform AngleX="0" AngleY="0"/>
            <RotateTransform Angle="0"/>
            <TranslateTransform X="0" Y="0"/>
        </TransformGroup>
    </Grid.RenderTransform>
    <Ellipse Name="Ellipse" >
        <Ellipse.Fill>
            <RadialGradientBrush GradientOrigin="0.258,0.21">
                <GradientStop x:Name="OuterColor" Offset="0.9"/>
                <GradientStop x:Name="InnerColor" Offset="0.312"/>
                <GradientStop Color="#FFFFFFFF" Offset="0"/>
            </RadialGradientBrush>
        </Ellipse.Fill>
    </Ellipse>
</Grid>

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WPF image swipe to change image like in iOS

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