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See my other thread for my original questions. http://social.msdn.microsoft.com/Forums/en-us/vbgeneral/thread/f3e50c89-05be-4786-9536-7eef88d6d350
http://social.msdn.microsoft.com/Forums/en-us/vbgeneral/thread/f3e50c89-05be-4786-9536-7eef88d6d350
So like I said before, I have a webcam capture and inventory script which I put together from various sample code. It works great, but I need to add a preview pause/ to break apart the capture and the save functions.
<pre>Imports System.Runtime.InteropServices
Public Class Form1
Const WM_CAP As Short = &H400S
Const WM_CAP_DRIVER_CONNECT As Integer = WM_CAP + 10
Const WM_CAP_DRIVER_DISCONNECT As Integer = WM_CAP + 11
Const WM_CAP_EDIT_COPY As Integer = WM_CAP + 30
Public Const WM_CAP_GET_STATUS As Integer = WM_CAP + 54
Public Const WM_CAP_DLG_VIDEOFORMAT As Integer = WM_CAP + 41
Const WM_CAP_SET_PREVIEW As Integer = WM_CAP + 50
Const WM_CAP_SET_PREVIEWRATE As Integer = WM_CAP + 52
Const WM_CAP_SET_SCALE As Integer = WM_CAP + 53
Const WS_CHILD As Integer = &H40000000
Const WS_VISIBLE As Integer = &H10000000
Const SWP_NOMOVE As Short = &H2S
Const SWP_NOSIZE As Short = 1
Const SWP_NOZORDER As Short = &H4S
Const HWND_BOTTOM As Short = 1
Dim iDevice As Integer = 0 Current device ID
Dim hHwnd As Integer Handle to preview window
Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
(ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, _
ByRef lParam As CAPSTATUS) As Boolean
Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
(ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Boolean, _
ByRef lParam As Integer) As Boolean
Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
(ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, _
ByRef lParam As Integer) As Boolean
Declare Function SetWindowPos Lib "user32" Alias "SetWindowPos" (ByVal hwnd As Integer, _
ByVal hWndInsertAfter As Integer, ByVal x As Integer, ByVal y As Integer, _
ByVal cx As Integer, ByVal cy As Integer, ByVal wFlags As Integer) As Integer
Declare Function DestroyWindow Lib "user32" (ByVal hndw As Integer) As Boolean
Structure POINTAPI
Dim x As Integer
Dim y As Integer
End Structure
Public Structure CAPSTATUS
Dim uiImageWidth As Integer // Width of the image
Dim uiImageHeight As Integer // Height of the image
Dim fLiveWindow As Integer // Now Previewing video?
Dim fOverlayWindow As Integer // Now Overlaying video?
Dim fScale As Integer // Scale image to client?
Dim ptScroll As POINTAPI // Scroll position
Dim fUsingDefaultPalette As Integer // Using default driver palette?
Dim fAudioHardware As Integer // Audio hardware present?
Dim fCapFileExists As Integer // Does capture file exist?
Dim dwCurrentVideoFrame As Integer // # of video frames captd
Dim dwCurrentVideoFramesDropped As Integer // # of video frames dropped
Dim dwCurrentWaveSamples As Integer // # of wave samples captd
Dim dwCurrentTimeElapsedMS As Integer // Elapsed capture duration
Dim hPalCurrent As Integer // Current palette in use
Dim fCapturingNow As Integer // Capture in progress?
Dim dwReturn As Integer // Error value after any operation
Dim wNumVideoAllocated As Integer // Actual number of video buffers
Dim wNumAudioAllocated As Integer // Actual number of audio buffers
End Structure
Declare Function capCreateCaptureWindowA Lib "avicap32.dll" _
(ByVal lpszWindowName As String, ByVal dwStyle As Integer, _
ByVal x As Integer, ByVal y As Integer, ByVal nWidth As Integer, _
ByVal nHeight As Short, ByVal hWndParent As Integer, _
ByVal nID As Integer) As Integer
Declare Function capGetDriverDescriptionA Lib "avicap32.dll" (ByVal wDriver As Short, _
ByVal lpszName As String, ByVal cbName As Integer, ByVal lpszVer As String, _
ByVal cbVer As Integer) As Boolean
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
LoadDeviceList()
If lstDevices.Items.Count > 0 Then
btnStart.Enabled = True
lstDevices.SelectedIndex = 0
btnStart.Enabled = True
Else
lstDevices.Items.Add("No Capture Device")
btnStart.Enabled = False
End If
Me.AutoScrollMinSize = New Size(100, 100)
btnStop.Enabled = False
btnSave.Enabled = False
picCapture.SizeMode = PictureBoxSizeMode.StretchImage
End Sub
Private Sub LoadDeviceList()
Dim strName As String = Space(100)
Dim strVer As String = Space(100)
Dim bReturn As Boolean
Dim x As Short = 0
Load name of all avialable devices into the lstDevices
Do
Get Driver name and version
bReturn = capGetDriverDescriptionA(x, strName, 100, strVer, 100)
If there was a device add device name to the list
If bReturn Then lstDevices.Items.Add(strName.Trim)
x += CType(1, Short)
Loop Until bReturn = False
End Sub
Private Sub OpenPreviewWindow()
Dim iHeight As Integer = picCapture.Height
Dim iWidth As Integer = picCapture.Width
Open Preview window in picturebox
hHwnd = capCreateCaptureWindowA(iDevice.ToString, WS_VISIBLE Or WS_CHILD, 0, 0, 1280, _
1024, picCapture.Handle.ToInt32, 0)
Connect to device
If SendMessage(hHwnd, WM_CAP_DRIVER_CONNECT, iDevice, 0) Then
Set the preview scale
SendMessage(hHwnd, WM_CAP_SET_SCALE, True, 0)
Set the preview rate in milliseconds
SendMessage(hHwnd, WM_CAP_SET_PREVIEWRATE, 66, 0)
Start previewing the image from the camera
SendMessage(hHwnd, WM_CAP_SET_PREVIEW, True, 0)
Resize window to fit in picturebox
SetWindowPos(hHwnd, HWND_BOTTOM, 0, 0, picCapture.Width, picCapture.Height, _
SWP_NOMOVE Or SWP_NOZORDER)
btnSave.Enabled = True
btnStop.Enabled = True
btnStart.Enabled = False
Else
Error connecting to device close window
DestroyWindow(hHwnd)
btnSave.Enabled = False
End If
End Sub
Private Sub btnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStart.Click
Dim r As Rectangle
iDevice = lstDevices.SelectedIndex
OpenPreviewWindow()
Dim bReturn As Boolean
Dim wSize As Integer
Dim s As CAPSTATUS
bReturn = SendMessage(hHwnd, WM_CAP_GET_STATUS, Marshal.SizeOf(s), s)
Debug.WriteLine(String.Format("Video Size {0} x {1}", s.uiImageWidth, s.uiImageHeight))
End Sub
Private Sub ClosePreviewWindow()
Disconnect from device
SendMessage(hHwnd, WM_CAP_DRIVER_DISCONNECT, iDevice, 0)
close window
DestroyWindow(hHwnd)
End Sub
Private Sub btnStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStop.Click
ClosePreviewWindow()
btnSave.Enabled = False
btnStart.Enabled = True
btnStop.Enabled = False
End Sub
Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
Dim data As IDataObject
Dim bmap As Bitmap
Copy image to clipboard
SendMessage(hHwnd, WM_CAP_EDIT_COPY, 0, 0)
Get image from clipboard and convert it to a bitmap
data = Clipboard.GetDataObject()
If data.GetDataPresent(GetType(System.Drawing.Bitmap)) Then
bmap = CType(data.GetData(GetType(System.Drawing.Bitmap)), Bitmap)
picCapture.Image = bmap
ClosePreviewWindow()
btnSave.Enabled = False
btnStop.Enabled = False
btnStart.Enabled = True
sfdImage.FileName = TextBox1.Text
Trace.Assert(Not (bmap Is Nothing))
If sfdImage.ShowDialog = DialogResult.OK Then
bmap.Save(sfdImage.FileName, Imaging.ImageFormat.Bmp)
End If
End If
End Sub
Private Sub Form1_Closing(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
If btnStop.Enabled Then
ClosePreviewWindow()
End If
End Sub
Private Sub SendMessage(hHwnd As Integer, WM_CAP_DLG_VIDEOFORMAT As Integer, p3 As Long, p4 As Long)
Throw New NotImplementedException
End Sub
End Class
[/code]
I was able to add a capture button, which triggered the capture of the image, but left the webcam still running and brought up the save dialog over the top. What I really need though is to hit Capture, and have the captured image display in the preview window.
then I can select save if I am happy or Start if I want to activate the camera again without saving. The goal being quality control, see the image before I save it.
Also I am looking at some of the jpeg conversion script, am I correct in my understanding that the script will need to save the image from the clipboard to a temporary location as a bmp then the conversion will come along and convert the bmp to jpeg as it
prompts for me for the file name and save location. Would I get just as good of results running a bmp-> jpg batch converter later?
Many many thanks
M
View the full article
http://social.msdn.microsoft.com/Forums/en-us/vbgeneral/thread/f3e50c89-05be-4786-9536-7eef88d6d350
So like I said before, I have a webcam capture and inventory script which I put together from various sample code. It works great, but I need to add a preview pause/ to break apart the capture and the save functions.
<pre>Imports System.Runtime.InteropServices
Public Class Form1
Const WM_CAP As Short = &H400S
Const WM_CAP_DRIVER_CONNECT As Integer = WM_CAP + 10
Const WM_CAP_DRIVER_DISCONNECT As Integer = WM_CAP + 11
Const WM_CAP_EDIT_COPY As Integer = WM_CAP + 30
Public Const WM_CAP_GET_STATUS As Integer = WM_CAP + 54
Public Const WM_CAP_DLG_VIDEOFORMAT As Integer = WM_CAP + 41
Const WM_CAP_SET_PREVIEW As Integer = WM_CAP + 50
Const WM_CAP_SET_PREVIEWRATE As Integer = WM_CAP + 52
Const WM_CAP_SET_SCALE As Integer = WM_CAP + 53
Const WS_CHILD As Integer = &H40000000
Const WS_VISIBLE As Integer = &H10000000
Const SWP_NOMOVE As Short = &H2S
Const SWP_NOSIZE As Short = 1
Const SWP_NOZORDER As Short = &H4S
Const HWND_BOTTOM As Short = 1
Dim iDevice As Integer = 0 Current device ID
Dim hHwnd As Integer Handle to preview window
Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
(ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, _
ByRef lParam As CAPSTATUS) As Boolean
Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
(ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Boolean, _
ByRef lParam As Integer) As Boolean
Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
(ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, _
ByRef lParam As Integer) As Boolean
Declare Function SetWindowPos Lib "user32" Alias "SetWindowPos" (ByVal hwnd As Integer, _
ByVal hWndInsertAfter As Integer, ByVal x As Integer, ByVal y As Integer, _
ByVal cx As Integer, ByVal cy As Integer, ByVal wFlags As Integer) As Integer
Declare Function DestroyWindow Lib "user32" (ByVal hndw As Integer) As Boolean
Structure POINTAPI
Dim x As Integer
Dim y As Integer
End Structure
Public Structure CAPSTATUS
Dim uiImageWidth As Integer // Width of the image
Dim uiImageHeight As Integer // Height of the image
Dim fLiveWindow As Integer // Now Previewing video?
Dim fOverlayWindow As Integer // Now Overlaying video?
Dim fScale As Integer // Scale image to client?
Dim ptScroll As POINTAPI // Scroll position
Dim fUsingDefaultPalette As Integer // Using default driver palette?
Dim fAudioHardware As Integer // Audio hardware present?
Dim fCapFileExists As Integer // Does capture file exist?
Dim dwCurrentVideoFrame As Integer // # of video frames captd
Dim dwCurrentVideoFramesDropped As Integer // # of video frames dropped
Dim dwCurrentWaveSamples As Integer // # of wave samples captd
Dim dwCurrentTimeElapsedMS As Integer // Elapsed capture duration
Dim hPalCurrent As Integer // Current palette in use
Dim fCapturingNow As Integer // Capture in progress?
Dim dwReturn As Integer // Error value after any operation
Dim wNumVideoAllocated As Integer // Actual number of video buffers
Dim wNumAudioAllocated As Integer // Actual number of audio buffers
End Structure
Declare Function capCreateCaptureWindowA Lib "avicap32.dll" _
(ByVal lpszWindowName As String, ByVal dwStyle As Integer, _
ByVal x As Integer, ByVal y As Integer, ByVal nWidth As Integer, _
ByVal nHeight As Short, ByVal hWndParent As Integer, _
ByVal nID As Integer) As Integer
Declare Function capGetDriverDescriptionA Lib "avicap32.dll" (ByVal wDriver As Short, _
ByVal lpszName As String, ByVal cbName As Integer, ByVal lpszVer As String, _
ByVal cbVer As Integer) As Boolean
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
LoadDeviceList()
If lstDevices.Items.Count > 0 Then
btnStart.Enabled = True
lstDevices.SelectedIndex = 0
btnStart.Enabled = True
Else
lstDevices.Items.Add("No Capture Device")
btnStart.Enabled = False
End If
Me.AutoScrollMinSize = New Size(100, 100)
btnStop.Enabled = False
btnSave.Enabled = False
picCapture.SizeMode = PictureBoxSizeMode.StretchImage
End Sub
Private Sub LoadDeviceList()
Dim strName As String = Space(100)
Dim strVer As String = Space(100)
Dim bReturn As Boolean
Dim x As Short = 0
Load name of all avialable devices into the lstDevices
Do
Get Driver name and version
bReturn = capGetDriverDescriptionA(x, strName, 100, strVer, 100)
If there was a device add device name to the list
If bReturn Then lstDevices.Items.Add(strName.Trim)
x += CType(1, Short)
Loop Until bReturn = False
End Sub
Private Sub OpenPreviewWindow()
Dim iHeight As Integer = picCapture.Height
Dim iWidth As Integer = picCapture.Width
Open Preview window in picturebox
hHwnd = capCreateCaptureWindowA(iDevice.ToString, WS_VISIBLE Or WS_CHILD, 0, 0, 1280, _
1024, picCapture.Handle.ToInt32, 0)
Connect to device
If SendMessage(hHwnd, WM_CAP_DRIVER_CONNECT, iDevice, 0) Then
Set the preview scale
SendMessage(hHwnd, WM_CAP_SET_SCALE, True, 0)
Set the preview rate in milliseconds
SendMessage(hHwnd, WM_CAP_SET_PREVIEWRATE, 66, 0)
Start previewing the image from the camera
SendMessage(hHwnd, WM_CAP_SET_PREVIEW, True, 0)
Resize window to fit in picturebox
SetWindowPos(hHwnd, HWND_BOTTOM, 0, 0, picCapture.Width, picCapture.Height, _
SWP_NOMOVE Or SWP_NOZORDER)
btnSave.Enabled = True
btnStop.Enabled = True
btnStart.Enabled = False
Else
Error connecting to device close window
DestroyWindow(hHwnd)
btnSave.Enabled = False
End If
End Sub
Private Sub btnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStart.Click
Dim r As Rectangle
iDevice = lstDevices.SelectedIndex
OpenPreviewWindow()
Dim bReturn As Boolean
Dim wSize As Integer
Dim s As CAPSTATUS
bReturn = SendMessage(hHwnd, WM_CAP_GET_STATUS, Marshal.SizeOf(s), s)
Debug.WriteLine(String.Format("Video Size {0} x {1}", s.uiImageWidth, s.uiImageHeight))
End Sub
Private Sub ClosePreviewWindow()
Disconnect from device
SendMessage(hHwnd, WM_CAP_DRIVER_DISCONNECT, iDevice, 0)
close window
DestroyWindow(hHwnd)
End Sub
Private Sub btnStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStop.Click
ClosePreviewWindow()
btnSave.Enabled = False
btnStart.Enabled = True
btnStop.Enabled = False
End Sub
Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
Dim data As IDataObject
Dim bmap As Bitmap
Copy image to clipboard
SendMessage(hHwnd, WM_CAP_EDIT_COPY, 0, 0)
Get image from clipboard and convert it to a bitmap
data = Clipboard.GetDataObject()
If data.GetDataPresent(GetType(System.Drawing.Bitmap)) Then
bmap = CType(data.GetData(GetType(System.Drawing.Bitmap)), Bitmap)
picCapture.Image = bmap
ClosePreviewWindow()
btnSave.Enabled = False
btnStop.Enabled = False
btnStart.Enabled = True
sfdImage.FileName = TextBox1.Text
Trace.Assert(Not (bmap Is Nothing))
If sfdImage.ShowDialog = DialogResult.OK Then
bmap.Save(sfdImage.FileName, Imaging.ImageFormat.Bmp)
End If
End If
End Sub
Private Sub Form1_Closing(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
If btnStop.Enabled Then
ClosePreviewWindow()
End If
End Sub
Private Sub SendMessage(hHwnd As Integer, WM_CAP_DLG_VIDEOFORMAT As Integer, p3 As Long, p4 As Long)
Throw New NotImplementedException
End Sub
End Class
[/code]
I was able to add a capture button, which triggered the capture of the image, but left the webcam still running and brought up the save dialog over the top. What I really need though is to hit Capture, and have the captured image display in the preview window.
then I can select save if I am happy or Start if I want to activate the camera again without saving. The goal being quality control, see the image before I save it.
Also I am looking at some of the jpeg conversion script, am I correct in my understanding that the script will need to save the image from the clipboard to a temporary location as a bmp then the conversion will come along and convert the bmp to jpeg as it
prompts for me for the file name and save location. Would I get just as good of results running a bmp-> jpg batch converter later?
Many many thanks
M
View the full article