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Convert VB source code to Delphi (it is using Windows API)

For VB/Delphi expert....

Public Function CaptureWindow(ByVal hWndSrc As Long, _
ByVal Client As Boolean, ByVal LeftSrc As Long, _
ByVal TopSrc As Long, ByVal WidthSrc As Long, _
ByVal HeightSrc As Long) As Picture

Dim hDCMemory As Long
Dim hBmp As Long
Dim hBmpPrev As Long
Dim r As Long
Dim hDCSrc As Long
Dim hPal As Long
Dim hPalPrev As Long
Dim RasterCapsScrn As Long
Dim HasPaletteScrn As Long
Dim PaletteSizeScrn As Long
Dim LogPal As LOGPALETTE

' Depending on the value of Client get the proper device context.
If Client Then
hDCSrc = GetDC(hWndSrc) ' Get device context for client area.
Else
hDCSrc = GetWindowDC(hWndSrc) ' Get device context for entire
' window.
End If

' Create a memory device context for the copy process.
hDCMemory = CreateCompatibleDC(hDCSrc)
' Create a bitmap and place it in the memory DC.
hBmp = CreateCompatibleBitmap(hDCSrc, WidthSrc, HeightSrc)
hBmpPrev = SelectObject(hDCMemory, hBmp)

' Get screen properties.
RasterCapsScrn = GetDeviceCaps(hDCSrc, RASTERCAPS) ' Raster
' capabilities.
HasPaletteScrn = RasterCapsScrn And RC_PALETTE ' Palette
' support.
PaletteSizeScrn = GetDeviceCaps(hDCSrc, SIZEPALETTE) ' Size of
' palette.

' If the screen has a palette make a copy and realize it.
If HasPaletteScrn And (PaletteSizeScrn = 256) Then
' Create a copy of the system palette.
LogPal.palVersion = &H300
LogPal.palNumEntries = 256
r = GetSystemPaletteEntries(hDCSrc, 0, 256, _
LogPal.palPalEntry(0))
hPal = CreatePalette(LogPal)
' Select the new palette into the memory DC and realize it.
hPalPrev = SelectPalette(hDCMemory, hPal, 0)
r = RealizePalette(hDCMemory)
End If

' Copy the on-screen image into the memory DC.
r = BitBlt(hDCMemory, 0, 0, WidthSrc, HeightSrc, hDCSrc, _
LeftSrc, TopSrc, vbSrcCopy)

' Remove the new copy of the on-screen image.
hBmp = SelectObject(hDCMemory, hBmpPrev)

' If the screen has a palette get back the palette that was
' selected in previously.
If HasPaletteScrn And (PaletteSizeScrn = 256) Then
hPal = SelectPalette(hDCMemory, hPalPrev, 0)
End If

' Release the device context resources back to the system.
r = DeleteDC(hDCMemory)
r = ReleaseDC(hWndSrc, hDCSrc)

' Call CreateBitmapPicture to create a picture object from the
' bitmap and palette handles. Then return the resulting picture
' object.
Set CaptureWindow = CreateBitmapPicture(hBmp, hPal)
End Function

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'
' CaptureForm
' - Captures an entire form including title bar and border.
'
' frmSrc
' - The Form object to capture.
'
' Returns
' - Returns a Picture object containing a bitmap of the entire
' form.
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'
Public Function CaptureForm(frmSrc As Form) As Picture
' Call CaptureWindow to capture the entire form given its window
' handle and then return the resulting Picture object.
Set CaptureForm = CaptureWindow(frmSrc.hWnd, False, 0, 0, _
frmSrc.ScaleX(frmSrc.Width, vbTwips, vbPixels), _
frmSrc.ScaleY(frmSrc.Height, vbTwips, vbPixels))
End Function

ASKER CERTIFIED SOLUTION

Jacco

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Jacco

Here is the second one:

function CaptureForm(frmSrc: TForm): TBitmap;
begin
// Call CaptureWindow to capture the entire form given its window
// handle and then return the resulting Picture object.
Result := CaptureWindow(frmSrc.Handle, False, 0, 0, frmSrc.Width, frmSrc.Height);
end;

Don't forget to put Windows, Graphics and Forms in the uses clause of the unit.

The function creates a bitmap which you have to destroy yourself!

Regards Jacco

Ashok

ASKER

Jacco

I get Undeclared identifier: 'CaptureWindow'
I am using Delphi 7.

Following first few lines are from my unit in which I tried your function.

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ExtCtrls, StdCtrls;

As you said, I have Windows, Graphics & Forms.

Ashok

Ashok

ASKER

So where is CaptureWindow ? Is it Windows API ? I do not think so.

Thanks,
Ashok

BlackTigerX

CaptureWindow is the first function he wrote for you... you need to put both functions in your code

Ashok

ASKER

OK I got it.

Jacco

Thanks BlackTigerX :-) I was busy coding another solution (this machine has no Email so no ding-dong ;-)

Ashok

ASKER

I was hoping to use this code which I found from MSDN site to use
inf Delphi so that it could capture inactive (also minimized) window,
but it is not working as I expected.

When a window is minimized, it gives blank canvas.
When the window is active but Task Manager on top (using Stay on top), it gives
window image with Task Manager window.
I wanted only the actual window's image.

Can this be done any other way?

Thanks,
Ashok