wpf - 使用 MatrixTransform 平滑动画？

Question

我正在尝试做一个矩阵动画​​，我同时缩放和转置 Canvas 。我发现的唯一方法是使用 MatrixTransform 和 MatrixAnimationUsingKeyFrames。由于似乎没有内置矩阵的任何插值(仅用于路径/旋转)，因此似乎唯一的选择是尝试构建插值和 DiscreteMatrixKeyFrame 自己。

我做了一个基本的实现，但它并不完全顺利，我不确定这是否是最好的方法以及如何处理帧率等。有人有改进的建议吗？这是代码:

        MatrixAnimationUsingKeyFrames anim = new MatrixAnimationUsingKeyFrames();
        int duration = 1;
        anim.KeyFrames = Interpolate(new Point(0, 0), centerPoint, 1, factor,100,duration);
        this.matrixTransform.BeginAnimation(MatrixTransform.MatrixProperty, anim,HandoffBehavior.Compose);


public MatrixKeyFrameCollection Interpolate(Point startPoint, Point endPoint, double startScale, double endScale, double framerate,double duration)
    {
        MatrixKeyFrameCollection keyframes = new MatrixKeyFrameCollection();

        double steps = duration * framerate;
        double milliSeconds = 1000 / framerate;
        double timeCounter = 0;



        double diffX = Math.Abs(startPoint.X-  endPoint.X);
        double xStep = diffX / steps;

        double diffY = Math.Abs(startPoint.Y - endPoint.Y);
        double yStep = diffY / steps;

        double diffScale= Math.Abs(startScale- endScale);
        double scaleStep = diffScale / steps;


        if (endPoint.Y < startPoint.Y)
        {
            yStep =  -yStep;
        }

        if (endPoint.X < startPoint.X)
        {
            xStep =  -xStep;
        }


        if (endScale < startScale)
        {
            scaleStep =  -scaleStep;
        }


        Point currentPoint = new Point();
        double currentScale = startScale;

        for (int i = 0; i < steps; i++)
        {
            keyframes.Add(new DiscreteMatrixKeyFrame(new Matrix(currentScale, 0, 0, currentScale, currentPoint.X, currentPoint.Y), KeyTime.FromTimeSpan(TimeSpan.FromMilliseconds(timeCounter))));
            currentPoint.X += xStep;
            currentPoint.Y += yStep;
            currentScale += scaleStep;
            timeCounter += milliSeconds;

        }

        keyframes.Add(new DiscreteMatrixKeyFrame(new Matrix(endScale, 0, 0, endScale, endPoint.X, endPoint.Y), KeyTime.FromTimeSpan(TimeSpan.FromMilliseconds(0))));

        return keyframes;

    }

Answer 1

尝试这个!只要您不旋转/剪切，它就可以解决问题。

using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Animation;

namespace MapControl
{
    public class LinearMatrixAnimation : AnimationTimeline
    {

        public Matrix? From
        {
            set { SetValue(FromProperty, value);}
            get { return (Matrix)GetValue(FromProperty); }
        }
        public static DependencyProperty FromProperty = DependencyProperty.Register("From", typeof(Matrix?), typeof(LinearMatrixAnimation), new PropertyMetadata(null));

        public Matrix? To
        {
            set { SetValue(ToProperty, value); }
            get { return (Matrix)GetValue(ToProperty); }
        }
        public static DependencyProperty ToProperty = DependencyProperty.Register("To", typeof(Matrix?), typeof(LinearMatrixAnimation), new PropertyMetadata(null));

        public LinearMatrixAnimation()
        {            
        }

        public LinearMatrixAnimation(Matrix from, Matrix to, Duration duration)
        {
            Duration = duration;
            From = from;
            To = to;
        }

        public override object GetCurrentValue(object defaultOriginValue, object defaultDestinationValue, AnimationClock animationClock)
        {
            if (animationClock.CurrentProgress == null)
            {
                return null;
            }

            double progress = animationClock.CurrentProgress.Value;
            Matrix from = From ?? (Matrix)defaultOriginValue;

            if (To.HasValue)
            {
                Matrix to = To.Value;
                Matrix newMatrix = new Matrix(((to.M11 - from.M11) * progress)+from.M11, 0, 0, ((to.M22 - from.M22) * progress)+from.M22,
                                              ((to.OffsetX - from.OffsetX) * progress) + from.OffsetX, ((to.OffsetY - from.OffsetY) * progress)+ from.OffsetY);
                return newMatrix;
            }

            return Matrix.Identity;
        }

        protected override System.Windows.Freezable CreateInstanceCore()
        {
            return new LinearMatrixAnimation();
        }

        public override System.Type  TargetPropertyType
        {
            get { return typeof(Matrix); }
        }
    }
}