Перевод холста WPF с высокими коэффициентами масштабирования не происходит гладко от источника

Это вызвано самим Canvas. Это не очень хорошо для более продвинутого рендеринга. Вам нужно использовать визуальный класс. Это немного сложнее, но вы получаете преимущество рендеринга на низком уровне.

Загрузка решения

Вот код: MainWindow.xaml

<Window x:Class="VisualTest.MainWindow"
 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 Title="VisualLayer" Height="350.4" Width="496.8"
 xmlns:local="clr-namespace:VisualTest"
>
<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto"></ColumnDefinition>
        <ColumnDefinition></ColumnDefinition>
    </Grid.ColumnDefinitions>

    <StackPanel Orientation="Vertical">
        <Button  Name="button1" Click="button1_Click"  Margin="5" Padding="5,0">
            Zoom WAY in to 0,0
        </Button>
        <Button Name="button2" Click="button2_Click" Margin="5" Padding="5,0">
            Zoom WAY in to 200, 200
        </Button>
        <Button Name="button3" Click="button3_Click" Margin="5" Padding="5,0">
            Zoom back
        </Button>
    </StackPanel>
    <local:DrawingCanvas Grid.Column="1" x:Name="drawingSurface" Background="White" ClipToBounds="True" 
                         MouseLeftButtonDown="drawingSurface_MouseLeftButtonDown"
            MouseLeftButtonUp="drawingSurface_MouseLeftButtonUp"
            MouseMove="drawingSurface_MouseMove">
    </local:DrawingCanvas>
</Grid>

MainWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace VisualTest
{
 /// <summary>
 /// Interaction logic for MainWindow.xaml
 /// </summary>
 public partial class MainWindow : Window
 {
    // Variables for dragging shapes.
    private bool isDragging = false;
    private Vector clickOffset;
    private DrawingVisual selectedVisual;
    // Drawing constants.
    private Brush drawingBrush = Brushes.Black;
    private Brush selectedDrawingBrush = Brushes.LightGoldenrodYellow;
    private Pen drawingPen = new Pen(Brushes.SteelBlue, 3);
    private Size squareSize = new Size(10, 10);

    public MainWindow()
    {
        InitializeComponent();
        DrawingVisual v = new DrawingVisual();
        DrawSquare(v, new Point(0, 0));
        drawingSurface.AddVisual(v);
        v = new DrawingVisual();
        DrawSquare(v, new Point(200, 200));
        drawingSurface.AddVisual(v);
    }

    private void button1_Click(object sender, RoutedEventArgs e)
    {
        TransformGroup tg = new TransformGroup();
        double scale = 1000000;
        double xCenter = 0;
        double yCenter = 0;
        double xOffset = (drawingSurface.ActualHeight / 2.0 - xCenter);
        double yOffset = (drawingSurface.ActualWidth / 2.0 - yCenter);
        ScaleTransform st = new ScaleTransform(scale, scale);
        st.CenterX = xCenter;
        st.CenterY = yCenter;
        TranslateTransform tt = new TranslateTransform(xOffset, yOffset);
        tg.Children.Add(st);
        tg.Children.Add(tt);
        drawingSurface.RenderTransform = st;
    }

    private void button2_Click(object sender, RoutedEventArgs e)
    {
        TransformGroup tg = new TransformGroup();
        double scale = 1000000;
        double xCenter = 200;
        double yCenter = 200;
        double xOffset = (drawingSurface.ActualHeight / 2.0 - xCenter);
        double yOffset = (drawingSurface.ActualWidth / 2.0 - yCenter);
        ScaleTransform st = new ScaleTransform(scale, scale);
        st.CenterX = xCenter;
        st.CenterY = yCenter;
        TranslateTransform tt = new TranslateTransform(xOffset, yOffset);
        tg.Children.Add(st);
        tg.Children.Add(tt);
        drawingSurface.RenderTransform = st;
    }

    private void button3_Click(object sender, RoutedEventArgs e)
    {
        ScaleTransform st = new ScaleTransform(1, 1);
        drawingSurface.RenderTransform = st;
    }

    private void drawingSurface_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        Point pointClicked = e.GetPosition(drawingSurface);
        DrawingVisual visual = drawingSurface.GetVisual(pointClicked);
        if (visual != null)
        {
            // Calculate the top-left corner of the square.
            // This is done by looking at the current bounds and
            // removing half the border (pen thickness).
            // An alternate solution would be to store the top-left
            // point of every visual in a collection in the 
            // DrawingCanvas, and provide this point when hit testing.
            Point topLeftCorner = new Point(
                visual.ContentBounds.TopLeft.X ,
                visual.ContentBounds.TopLeft.Y );
            DrawSquare(visual, topLeftCorner);

            clickOffset = topLeftCorner - pointClicked;
            isDragging = true;

            if (selectedVisual != null && selectedVisual != visual)
            {
                // The selection has changed. Clear the previous selection.
                ClearSelection();
            }
            selectedVisual = visual;
        }          
    }

    // Rendering the square.
    private void DrawSquare(DrawingVisual visual, Point topLeftCorner)
    {
        using (DrawingContext dc = visual.RenderOpen())
        {
            Brush brush = drawingBrush;
            dc.DrawRectangle(brush, null,
                new Rect(topLeftCorner, squareSize));
        }
    }

    private void drawingSurface_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
    {
        isDragging = false;
    }

    private void ClearSelection()
    {
        Point topLeftCorner = new Point(
                    selectedVisual.ContentBounds.TopLeft.X ,
                    selectedVisual.ContentBounds.TopLeft.Y );
        DrawSquare(selectedVisual, topLeftCorner);
        selectedVisual = null;
    }

    private void drawingSurface_MouseMove(object sender, MouseEventArgs e)
    {
        if (isDragging)
        {
            Point pointDragged = e.GetPosition(drawingSurface) + clickOffset;
            DrawSquare(selectedVisual, pointDragged);
        }
    }
 }
}

DrawingCanvas.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Media;
using System.Windows.Controls;
using System.Windows;

namespace VisualTest
{
 public class DrawingCanvas : Panel
 {
    private List<Visual> visuals = new List<Visual>();

    protected override Visual GetVisualChild(int index)
    {
        return visuals[index];
    }
    protected override int VisualChildrenCount
    {
        get
        {
            return visuals.Count;
        }
    }

    public void AddVisual(Visual visual)
    {
        visuals.Add(visual);

        base.AddVisualChild(visual);
        base.AddLogicalChild(visual);
    }

    public void DeleteVisual(Visual visual)
    {
        visuals.Remove(visual);

        base.RemoveVisualChild(visual);
        base.RemoveLogicalChild(visual);            
    }

    public DrawingVisual GetVisual(Point point)
    {
        HitTestResult hitResult = VisualTreeHelper.HitTest(this, point);
        return hitResult.VisualHit as DrawingVisual;            
    }

    private List<DrawingVisual> hits = new List<DrawingVisual>();
    public List<DrawingVisual> GetVisuals(Geometry region)
    {
        hits.Clear();
        GeometryHitTestParameters parameters = new GeometryHitTestParameters(region);
        HitTestResultCallback callback = new HitTestResultCallback(this.HitTestCallback);
        VisualTreeHelper.HitTest(this, null, callback, parameters);
        return hits;
    }

    private HitTestResultBehavior HitTestCallback(HitTestResult result)
    {
        GeometryHitTestResult geometryResult = (GeometryHitTestResult)result;
        DrawingVisual visual = result.VisualHit as DrawingVisual;
        if (visual != null &&
            geometryResult.IntersectionDetail == IntersectionDetail.FullyInside)
        {
            hits.Add(visual);
        }
        return HitTestResultBehavior.Continue;
    }

 }
}

Систему перетаскивания нужно переписать. Идея проста, но реализация немного сложна.