Correction

Greetings,

I've written and enclosed a demo app that creates several geometries on a DrawingVisual and transforms the DrawingVisual based on a MouseMove position. Visually, the performance is good, but a little choppy. The final application may have a geometry count five to ten times whats demonstrated. As more geometries are added the expectation is that the frame rate will be approxiamtely 30 during MouseMove to enable panning that is smooth to the eye. The demo app, which is extracted from a more complex control using three DrawingVisuals, crawls at 6-12 fps during MouseMove translate transforms. The demo is an accurate sample of what occurs in the other app.

While running the enclosed demo app, Perforator shows a frame rate of 15 when I click on the DrawingVisual and drag it from left to right. I am hoping to see a frame rate of at least 30. Does anyone have suggestions to increase the frame rate to 30 during MouseMove transforms Or, to make the transforms appear completely smooth to the eye

Thanks in advance,

Rana Ian

--- Ready for Copy-Paste into Window1.xaml.cs ---

using System;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Data;

using System.Windows.Documents;

using System.Windows.Media;

using System.Windows.Media.Imaging;

using System.Windows.Shapes;

using System.Collections.Generic;

using System.Windows.Input;

namespace XAxisDemo

public partial class Window1 : Window

public Window1()

InitializeComponent();

this.Loaded += Window_Loaded;

void Window_Loaded(object sender, RoutedEventArgs e)

this.Width = 1300;

this.Height = 700;

this.Content = new ChartHost();

public class ChartHost : FrameworkElement

#region Fields

VisualCollection m_vcChildren;

SolidColorBrush m_TextBrush;

Pen m_TickPen;

SolidColorBrush m_MarginBrush;

Glyphs m_Glyphs;

GeometryGroup m_MarginGeometry;

GeometryGroup m_TickGeometry;

GeometryGroup m_BottomTextGeometry;

GeometryGroup m_TopTextGeometry;

DrawingVisual m_DrawingVisual;

TranslateTransform m_DrawingVisualTransform;

TranslateTransform m_InitialTransform;

Point m_InitialPoint;

#region Constructors

public ChartHost()

m_vcChildren = new VisualCollection(this);

// Reflect the the Y-axis so that

// 0,0 begins at the lower left corner of FrameworkElement

this.RenderTransformOrigin = new Point(0.5, 0.5);

this.RenderTransform = new ScaleTransform(1, -1);

m_TextBrush = Brushes.Gray;

m_TickPen = new Pen(Brushes.DimGray, 1);

m_TickPen.Freeze();

m_MarginBrush = Brushes.AntiqueWhite;

m_Glyphs = new Glyphs();

m_Glyphs.FontUri = new Uri("c:\\windows\\fonts\\arial.ttf");

m_Glyphs.FontRenderingEmSize = 12;

#region Properties

public VisualCollection Children

set

m_vcChildren = value;

get

return m_vcChildren;

protected override int VisualChildrenCount

get

return m_vcChildren.Count;

#region Methods

protected override Visual GetVisualChild(int index)

if (index < 0 || index > m_vcChildren.Count)

throw new ArgumentOutOfRangeException();

return m_vcChildren[index];

protected override Size ArrangeOverride(Size finalSize)

this.InitializeVisual(finalSize);

return base.ArrangeOverride(finalSize);

void InitializeVisual(Size finalSize)

m_vcChildren.Clear();

m_MarginGeometry = new GeometryGroup();

m_TickGeometry = new GeometryGroup();

m_BottomTextGeometry = new GeometryGroup();

m_TopTextGeometry = new GeometryGroup();

#region Create Time & Pixel Points

DateTime start = new DateTime(2010, 1, 1, 0, 0, 0, 0);

DateTime stop = new DateTime(2010, 1, 2, 0, 0, 0, 0);

TimeSpan tsIncrement = new TimeSpan(0, 1, 0);

List<DateTime> lTimes = new List<DateTime>(1440);

DoubleCollection dcPixels = new DoubleCollection(1440);

double dPixel = 0;

DateTime dtCurrent = start;

while (dtCurrent < stop)

lTimes.Add(dtCurrent);

dcPixels.Add(dPixel);

dtCurrent = dtCurrent.Add(tsIncrement);

dPixel += 4;

double dMarginHeight = 22;

double dMarginLength = dcPixels[dcPixels.Count - 1];

double dTopMarginBase = finalSize.Height - dMarginHeight;

double dTickHeight = 8;

double dBottomTickBase = dMarginHeight - dTickHeight;

double dTopTickTop = dTopMarginBase + dTickHeight;

double dTextPadding = 3;

#region Create Margin Geometry

// lower left corner is origin

Rect bottomRect = new Rect(

0,

0,

dMarginLength,

dMarginHeight);

m_MarginGeometry.Children.Add(new RectangleGeometry(bottomRect));

Rect topRect = new Rect(

0,

dTopMarginBase,

dMarginLength,

dMarginHeight);

m_MarginGeometry.Children.Add(new RectangleGeometry(topRect));

#region Create Tick & Text

for (int n = 0; n < lTimes.Count; n++)

double currentPixelX = dcPixels[n];

DateTime currentTime = lTimes[n];

bool bIsHour = currentTime.Minute == 0;

bool bIs20Minute = currentTime.Minute % 20 == 0;

bool bIs40Minute = currentTime.Minute % 40 == 0;

if (bIsHour || bIs20Minute || bIs40Minute)

// Bottom Tick

Point startPoint = new Point(currentPixelX, dBottomTickBase);

Point endPoint = new Point(currentPixelX, dMarginHeight);

LineGeometry topTick = new LineGeometry(startPoint, endPoint);

m_TickGeometry.Children.Add(topTick);

// Top Tick

startPoint = new Point(currentPixelX, dTopMarginBase);

endPoint = new Point(currentPixelX, dTopTickTop);

LineGeometry bottomTick = new LineGeometry(startPoint, endPoint);

m_TickGeometry.Children.Add(bottomTick);

// Text

if (bIsHour)

m_Glyphs.UnicodeString = currentTime.ToString("htt");

else

m_Glyphs.UnicodeString = currentTime.ToString("m.").TrimEnd('.');

Geometry glyphGeometry = m_Glyphs.ToGlyphRun().BuildGeometry();

m_Glyphs.OriginX = currentPixelX - (glyphGeometry.Bounds.Width / 2);

m_Glyphs.OriginY = 0;

Geometry bottomGlyphGeometry = m_Glyphs.ToGlyphRun().BuildGeometry();

m_BottomTextGeometry.Children.Add(bottomGlyphGeometry);

Geometry topGlyphGeometry = m_Glyphs.ToGlyphRun().BuildGeometry();

m_TopTextGeometry.Children.Add(topGlyphGeometry);

// Compensate for y-axis inversion

ScaleTransform scaleTransform = new ScaleTransform(1, -1);

#region Bottom Text Compensation

TransformGroup tgBottom = new TransformGroup();

tgBottom.Children.Add(scaleTransform);

TranslateTransform ttBottom = new TranslateTransform(0, dTextPadding);

tgBottom.Children.Add(ttBottom);

m_BottomTextGeometry.Transform = tgBottom;

#region Top Text Compensation

TransformGroup tgTop = new TransformGroup();

tgTop.Children.Add(scaleTransform);

double dOffsetY = dTopMarginBase + dTickHeight + dTextPadding;

TranslateTransform ttTop = new TranslateTransform(0, dOffsetY);

tgTop.Children.Add(ttTop);

m_TopTextGeometry.Transform = tgTop;

m_MarginGeometry.Freeze();

m_TickGeometry.Freeze();

m_BottomTextGeometry.Freeze();

m_TopTextGeometry.Freeze();

m_DrawingVisual = new DrawingVisual();

m_DrawingVisualTransform = new TranslateTransform(0, 0);

m_DrawingVisual.Transform = m_DrawingVisualTransform;

DrawingContext drawingContext = m_DrawingVisual.RenderOpen();

using (drawingContext)

drawingContext.DrawGeometry(m_MarginBrush, null, m_MarginGeometry);

drawingContext.DrawGeometry(null, m_TickPen, m_TickGeometry);

drawingContext.DrawGeometry(m_TextBrush, null, m_BottomTextGeometry);

drawingContext.DrawGeometry(m_TextBrush, null, m_TopTextGeometry);

m_vcChildren.Add(m_DrawingVisual);

protected override void OnMouseLeftButtonDown(MouseButtonEventArgs e)

base.OnMouseLeftButtonDown(e);

m_InitialPoint = e.GetPosition(this);

m_DrawingVisualTransform = m_DrawingVisual.Transform as TranslateTransform;

m_InitialTransform = m_DrawingVisualTransform.Clone();

m_InitialTransform.Freeze();

Mouse.Capture(this);

protected override void OnMouseLeftButtonUp(MouseButtonEventArgs e)

base.OnMouseLeftButtonUp(e);

m_InitialPoint = null;

Mouse.Capture(null);

protected override void OnMouseMove(MouseEventArgs e)

base.OnMouseMove(e);

if (m_InitialPoint != null)

Point currentPoint = e.GetPosition(this);

Vector vDelta =

currentPoint -

m_InitialPoint;

double dNewOffsetX =

m_InitialTransform.Value.OffsetX +

vDelta.Value.X;

m_DrawingVisualTransform.X = dNewOffsetX;