Microsoft KB Archive/141072

= How To Size a Picture Box Dynamically to Fit an AVI Image =

Article ID: 141072

Article Last Modified on 11/3/2003

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APPLIES TO


 * Microsoft Visual Basic 4.0 Professional Edition
 * Microsoft Visual Basic 4.0 32-Bit Enterprise Edition

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This article was previously published under Q141072



SUMMARY
To size a picture box to fit an AVI image at run time, you must first get the dimensions of the AVI file. This article demonstrates how to do it.



MORE INFORMATION
The example uses the mciSendCommand function to get the dimensions of the AVI file currently referenced by an MCI control.

Step-by-Step Example
 Start a new project in Visual Basic. Add a module (.BAS) file, and make sure the MCI control is included in the project. Add a MCI control (MMControl1), a Command Button (Command1), and a Picture box (Picture1) to Form1. Set Form1's ScaleMode property to Pixels (3).  In the General declarations section of the .BAS file, add this code: Type RECT Left As Long Top As Long Right As Long Bottom As Long End Type

Type MCI_OVLY_RECT_PARMS dwCallback As Long rc As RECT End Type

Global Const MCI_OVLY_WHERE_SOURCE = &H20000 Global Const MCI_OVLY_WHERE_DESTINATION = &H40000 Global Const MCI_WHERE = &H843

'Enter the following Declare statement:

Declare Function mciSendCommand Lib "winmm.dll" _ Alias "mciSendCommandA" ( _        ByVal wDeviceID As Long, _         ByVal uMessage As Long, _         ByVal dwParam1 As Long,         dwParam2 As Any) As Long

' Enter the following Declare statement: Declare Function mciGetErrorString Lib "winmm.dll" _ Alias "mciGetErrorStringA" ( _        ByVal dwError As Long, _         ByVal lpstrBuffer As String, _         ByVal uLength As Long) As Long

  In the Command1_Click method for the Command button on Form1, enter this code: Sub Command1_Click Const MB_OK = 0 Const MB_ICONSTOP = 16

Dim Retval&, Buffer$ Dim dwParam2 As MCI_OVLY_RECT_PARMS

MMControl1.Command = "Close" MMControl1.Filename = "WndSurf1.avi" 'Sample AVI file to be                                               'played.

'Get the MCI control to display the video in Picture1: MMControl1.hWndDisplay = Picture1.hWnd

MMControl1.Command = "Open"

'Initialize the structure being passed with mciSendCommand, and 'set it in case you want to use the Notify property: dwParam2.dwCallback = MMControl1.hWnd dwParam2.rc.Left = 0 dwParam2.rc.Top = 0 dwParam2.rc.Right = 0 dwParam2.rc.Bottom = 0

'Send the message: 'Enter the following two lines as one, single line of code: Retval& = mciSendCommand(MMControl1.DeviceID, MCI_WHERE,               MCI_OVLY_WHERE_SOURCE, dwParam2)

If Retval& <> 0 Then ' An error occurred. Buffer$ = Space$(100) 'Get a description of the error: Retval& = mciGetErrorString(Retval&, Buffer$, Len(Buffer$)) MsgBox Trim$(Buffer$), MB_OK + MB_ICONSTOP, "ERROR" Else 'Resize the picture box: Picture1.Width = dwParam2.rc.right - dwParam2.rc.left Picture1.Height = dwParam2.rc.bottom - dwParam2.rc.top

'Play the video: MMControl1.Wait = True ' Wait for the next command to complete MMControl1.Command = "play" 'Play the video clip MMControl1.Command = "close" End If  End Sub

 Test the program by pressing the F5 key to run it, and clicking the command button. The AVI file will play back in the picture box, which will have been resized to fit the video clip exactly.

Additional query words: 3.00 4.00 MCI AVI vb4win vb432

Keywords: kbwndw kbcode KB141072

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