Calvin Hsia's WebLog : WPF

What is your computer doing with all that memory? Write your own memory browser

Calvin_Hsia — Mon, 19 Oct 2009 18:53:00 GMT

What is your computer doing with all that memory? There are various kinds of memory allocated and used in each process. These include:

· Managed memory (VB.Net, C#, managed C++)

· Heap memory

· Stacks

· Images (files loaded into a process)

VirtualAlloc is the basis of these allocations. If a process needs more of these types of memory, VirtualAlloc is called.

You can inspect the various kinds of memory by running the sample code below. It offers a list of current processes, from which you dbl-click one to inspect.

Once you choose a process, a snapshot of all Virtual memory allocations is shown in a ListView, along with the size, type, etc. If it’s an image, the filename is shown too. Hovering over addresses shows the memory contents in a tooltip. Double click to open another window with the entire memory contents. You can read strings in memory in these displays.

One can imagine this being the base of your own custom Task Manager. Perhaps you want to search for all strings in all processes. “Microsoft” occurs quite often!

Imagine taking a memory snapshot of a process, doing something in that process, then taking another snapshot and displaying the difference.

Caveats: you may not have rights to read some processes or some memory. Also, if you build to 32 bit (Project Options->Compile->AdvancedCompileOptions->TargetCPU->AnyCpu) and run on 64 bit, you might have problems.

It can examine both 32 and 64 bit processes. If you get Access Denied on some processes, you might have better luck running it as Administrator

Start Visual Studio 2008

File->New Project->VB WPF Application.

Open Window1.xaml.vb, replace the contents (about 650 lines) with the sample below.

Cartoon animation program

Calvin_Hsia — Thu, 29 Jan 2009 23:16:00 GMT

A cartoon can be thought of as a series of drawings. To simulate movement, the drawings can be slightly different from each other.

Remember drawing simple cartoons using a pad of paper? Simply flipping through the pages made the drawings come to life.

This was tedious work: a computer can help.

Just after first IBM PC came out in Aug 81, I wrote a cartoon animation program in C++ and assembly code. The concept was very simple: just use the mouse (I had to write my own mouse driver for a RS-232 serial mouse and had to hijack the COM1 port for my DOS program) to let the user draw some lines on the screen. Then the user could save those lines as a cartoon frame, and then draw another frame. The program could then calculate multiple frames in between the user created frames, creating smooth animation.

That early 80's version of cartoon still runs on XP (although it writes directly to the video memory so it requires full screen mode.

It doesn't run on Vista (I think you can download a DOS compatible window to make it work.)

A zip file of the 80's version is available here. Unzip the contents to a folder (check out the date stamps!), then run cartoon.exe and hit Shift-A.

It includes some stored samples, like flying birds, alphabet, basketball. Because this was written before Windows, it won't work with your mouse. You can see the main menu bar at the top. The only thing you can do with this program is run the stored samples by hitting Shift-A. Q will Quit. Try typing other chars to invoke various commands.

If you get it to run on Vista, please let me know the details.

About 10 years ago, I wrote another version of Cartoon in Foxpro and it was modified and published as a Solution Sample.

Start Visual Foxpro, Task Pane, Solution Samples. In the "Search for sample" text, box, type in Animation. "Display line animation in a form"

You can run the form, or click on the button on the right of the task pane that opens the form in the Form Designer, so you can see the source code.

You can also open the form in the Class Browser, then export the code into a single file using the "View Class Code" button.

Foxpro excerpt of the inbetween algorithm (notice how cursors (in-memory data tables) are used)

SELECT (lcTable)

DO WHILE !EOF("shadow")

mr = recno()

mr2 = recno("shadow")

FOR nb = 0 TO nBetween

THISFORMSET.frmAnimation.cls

GO mr

IF mr2 < RECCOUNT("shadow")

GO mr2 IN shadow

ENDIF

nFrames1 = &lcTable..frameno

nFrames2 = shadow.frameno

SCAN WHILE &lcTable..frameno = nFrames1

nx1 = &lcTable..x1 + nb * (shadow.x1 - &lcTable..x1) / nBetween

ny1 = &lcTable..y1 + nb * (shadow.y1 - &lcTable..y1) / nBetween

nx2 = &lcTable..x2 + nb * (shadow.x2 - &lcTable..x2) / nBetween

ny2 = &lcTable..y2 + nb * (shadow.y2 - &lcTable..y2) / nBetween

THISFORMSET.frmAnimation.line(nx1,ny1,nx2,ny2)

IF !EOF("shadow")

SKIP IN shadow

IF shadow.frameno # nFrames2

SKIP -1 IN shadow

ENDIF

ENDSCAN

SELECT shadow

IF !EOF()

SKIP

LOCATE REST FOR shadow.Frameno # nFrames2

ENDIF

SELECT (lcTable)

wait wind "" time .05

ENDFOR

ENDDO

USE IN shadow

SCAN REST

THISFORMSET.frmAnimation.line(x1,y1,x2,y2)

ENDSCAN

THISFORMSET.frmAnimation.frameno = nFrames1 + 1

Below is a more up to date example using WPF. The equivalent animation code is in tmr_tick().

Try running it, hitting the Demo button.

Start Visual Studio 2008.

Choose File->New Project->Visual Basic->WPF Application.

(This also works with Temporary projects)

Open Window1.xaml.vb. Paste in the code below, then hit F5 to run.

I had my wife and kids playing with it for quite a while!

Try adding a frame or MouseWheel while a cartoon is playing.

Try right click and then draw: it changes the way you draw.

Experiment with using a touchpad and a mouse for drawing.

Try using variable frame rates. Add a feature to save/restore the current cartoon.

Try drawing your name, or the letters of the alphabet.

My original had features like copy/paste from frames, color fill

You can use HWndHost to host a Win32 HWnd window inside a WPF element

Calvin_Hsia — Sat, 29 Nov 2008 09:21:00 GMT

Suppose you have some old code lying around that creates a Win32 window with an HWnd (perhaps ATL, MFC, or just C/ C++). For example, if you type some erroneous code into a VB application in Visual Studio:

Dim x=4: catch ex As Exception

The “Exception” will be squiggled and the end of the squiggle will have a red underline, indicating the presence of a Smart Tag.

You can move your mouse over the red underline or hit Ctrl-Period to invoke the smart tag suggestions for fixing the error. In this case, 2 suggested fixes are suggested in the smart tag menu: to insert Try/End Try in various places.

These suggested fixes show a preview right in the smart tag menu of what the effect is of each possible correction. These windows were written originally with Win32 Hwnds, using ATL.

You might want to take these old Windows and host them in a more modern application, using Windows Presentation Foundation

The sample below creates 4 identical Win32 HWnd windows hosted inside an HwndHost control. This control is then put into 3 WPF Popups and 1 WPF Window. The Win32 windows are simple and the WM_PAINT message just paints green & blue rectangles.

The 3 popups are identical, except that:

#1 has AllowTransparency = false. The Win32 hWnd window shows just fine

#2 has AllowTransparency = true. The Win32 hWnd window doesn’t show at all, but it can be discovered by using Spy++

#3 has AllowTransparency = true, but with the StackPanel inside with a Transparent Background. The Win32 hWnd doesn’t show at all, and you can even click through the popup

A Popup with AllowsTransparency = True requires Full Trust security. See http://blogs.msdn.com/dwayneneed/archive/2008/09/08/transparent-windows-in-wpf.aspx

Start Visual Studio (I was using VS 2008)

Choose File->New Project->Visual Basic->WPF Application.

(This also works with Temporary projects)

Open Window1.xaml.vb. Paste in the code below, then hit F5 to run. Try clicking on the various areas.

A WPF version of the Typing Tutor game

Calvin_Hsia — Thu, 03 Jul 2008 00:18:00 GMT

In my prior post I show a Windows Form version of the typing tutor game.

Here is a WPF version.

Start Visual Studio 2008. Choose File->New->Project->VB->WPF Application. Dbl-Click the form in the designer to open the code window. Paste in the code below.

Notice how the logic differs from the WinForm version. In that version, the position of the letter object is changed by manipulating the Top and Left properties of that object. In this WPF version, Attached Properties are changed: the child objects specify values for a property that is actually in the container. The position of the letter objects ( which are instances of a class that inherits from WPF Label) is manipulated via the Canvas.SetTop and SetLeft static methods.

Class Window1

Dim WithEvents oTimer As Timers.Timer

Dim nScore As Integer = 0

Dim nTicks = 0

Dim nHighScore As Integer = 0

Dim nInterval = 100

Const MAXLETS = 10

Dim aLets(MAXLETS - 1) As MyLabel

Dim nMaxSecs = 30

Declare Function Beep Lib "kernel32" (ByVal nFreq As Int32, ByVal nDura As Int32) As Integer

Dim oRand As New Random

Dim sHighScoreFile = My.Application.Info.DirectoryPath + IO.Path.DirectorySeparatorChar + "le"

Private Sub Window1_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded

Me.Left = 200

Me.Width = 600

Me.Height = 300

Dim oCanvas As New Canvas

Me.Content = oCanvas

For i = 0 To MAXLETS - 1

Dim oLbl = New MyLabel

oCanvas.Children.Add(oLbl)

Me.aLets(i) = oLbl

If My.Computer.FileSystem.FileExists(sHighScoreFile) Then

Me.nHighScore = Int(Val(My.Computer.FileSystem.ReadAllText(sHighScoreFile)))

End If

oTimer = New Timers.Timer

oTimer.Interval = Me.nInterval

oTimer.Start()

End Sub

Private Sub Form1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Input.KeyEventArgs) Handles Me.KeyDown

If e.Key = Key.Escape Then 'escape key

Me.Close()

Else

Dim oGotOne As MyLabel = Nothing

For i = 0 To MAXLETS - 1

With Me.aLets(i)

If .Visibility = Windows.Visibility.Visible And CType(.Content, TextBlock).Text = e.Key.ToString.ToUpper Then

If oGotOne Is Nothing OrElse Canvas.GetLeft(Me.aLets(i)) < Canvas.GetLeft(oGotOne) Then ' get leftmost

oGotOne = Me.aLets(i)

End If

End With

If oGotOne Is Nothing Then

Me.BadOne(50) ' no match: penalty

Else

oGotOne.Visibility = Windows.Visibility.Hidden

Me.nScore += Canvas.GetLeft(oGotOne) / 10 ' higher score for rightmost

End If

End Sub

Delegate Sub TimerTickMainThread()

Private Sub oTimer_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles oTimer.Elapsed

' the timer tick occurs on a background thread: let's invoke the processing on the main (UI) thread.

Dispatcher.Invoke(Windows.Threading.DispatcherPriority.Background, New TimerTickMainThread(AddressOf oTimer_TickMainThread))

End Sub

Private Sub oTimer_TickMainThread()

Me.nTicks += 1

Dim nSecs = Me.nTicks * Me.nInterval / 1000

If nSecs > Me.nMaxSecs Then ' out of time?

oTimer.Stop()

For i = 0 To MAXLETS - 1

Me.aLets(i).Visibility = Windows.Visibility.Hidden

If Me.nHighScore < Me.nScore Then

MsgBox("New High Score: " + Me.nScore.ToString + _

"! Old = " + Me.nHighScore.ToString, MsgBoxStyle.Exclamation)

Me.nHighScore = Me.nScore

My.Computer.FileSystem.WriteAllText(Me.sHighScoreFile, Me.nHighScore.ToString, 0)

Else

MsgBox("Your Score: " + Me.nScore.ToString + " High Score = " + Me.nHighScore.ToString)

End If

Me.nScore = 0 ' restart

Me.nTicks = 0

oTimer.Start()

Else

Me.Title = Me.nScore.ToString + " " + Int(Me.nMaxSecs - nSecs).ToString

For i = 0 To MAXLETS - 1

Dim oLet = Me.aLets(i)

With oLet

If .Visibility = Windows.Visibility.Visible Then

Canvas.SetLeft(oLet, Canvas.GetLeft(oLet) - .dx) '.Left -= .dx

If Canvas.GetLeft(oLet) <= 0 Then

.Visibility = Windows.Visibility.Hidden

Me.BadOne(100)

End If

Else

Dim nFactor = nSecs / Me.nMaxSecs ' 0 - 1

If oRand.NextDouble < 0.5 * nFactor Then

.dx = 1 + oRand.NextDouble * 15 * nFactor

Canvas.SetLeft(oLet, Me.Width - .dx - 10) '.Left = Me.Width - .dx - 10

CType(.Content, TextBlock).Foreground = _

New SolidColorBrush(Color.FromArgb(255, 0, 0, Me.nTicks * 100 Mod 256))

'.ForeColor = Color.FromArgb(Me.nTicks * 100 Mod 256)

Canvas.SetTop(oLet, 0.8 * (oRand.NextDouble * Me.Height)) '.Top = 0.8 * (oRand.NextDouble * Me.Height)

CType(.Content, TextBlock).Text = Chr(Int(65 + oRand.NextDouble * 26)) ' note: VB Rounds, so we need to use Int()

.Visibility = Windows.Visibility.Visible

End If

End With

End If

End Sub

Sub BadOne(ByVal nHowBad As Integer)

Me.nScore = Math.Max(0, Me.nScore - nHowBad)

Beep(2000, 20)

End Sub

Class MyLabel

Inherits Label

Public dx As Integer = 1

Sub New()

Me.Visibility = Windows.Visibility.Hidden

Me.Height = 32

Me.Width = 43

Dim tb As New TextBlock

tb.Visibility = Windows.Visibility.Visible

Me.Content = tb

tb.FontFamily = New FontFamily("Verdana")

tb.FontSize = 20

tb.FontWeight = FontWeights.Heavy

'Me.Font = New Font("Verdana", 20, FontStyle.Bold)

End Sub

End Class