[RESOLVED] Image to Buffer

[XRsTX]

Hello all, I'm making an application when once the image is changed from (picImage), which is a PictureBox; the Picture from picImage is saved into Buffered Memory (stdPicture in my choice) to be used as Checkpoints incase the user decides to relay back to another one.

Here is parts of my code so far:

  Private History(255) As New StdPicture
  Private CurrentHistoryNumber As Long 'what history point we are at.

   Function MakeHistoryPoint(ByVal HistoryReason As String)
     If CurrentHistoryNumber& < 255 Then
      Set History(CurrentHistoryNumber&) = retrieveImage(picImage)
       CurrentHistoryNumber& = CurrentHistoryNumber& + 1
        lstHistory.AddItem HistoryReason$
     End If
   End Function

   Private Function retrieveImage(ByVal SrcDC As PictureBox) As StdPicture
    Dim tempPicture As New StdPicture
     Call BitBlt(testOBJ.Handle, 0, 0, SrcDC.Width, SrcDC.Height, SrcDC.hDC, 0, 0, vbSrcCopy)
      Set retrieveImage = tempPicture
   End Function

My code works and all, but it when I try to retrieve the image from the History it does not show anything, this is the code I use to show the image into another picturebox (picSnapshot):

  Call BitBlt(picSnapshot.hDC, 0, 0, History(lstHistory.ListIndex).Width, _
  History(lstHistory.ListIndex).Height, History(lstHistory.ListIndex), 0, 0, vbSrcCopy)

I do notice that History(?) whatever's value is always at 0, meaning no picture was copied or something...does anyone have any clue what i'm doing wrong? Thanks,

RsT

[Edgemeal]

In your Call BitBlt(picSnapshot.hDC.....

For the source you have History(lstHistory.ListIndex) , shouldn't that be,
History(lstHistory.ListIndex).hDC ?

[XRsTX]

No i think it is directly handled like that..or by the .handle element which i have also tried (both run compiled correctly), but they do not show the image in the buffer..does anyone have any clue why?

[Milk]

You can't BitBlt to a StdPicture, BitBlt requires a Device Context as source and destination.

If you try...

Debug.print BitBlt(testOBJ.Handle, 0, 0, SrcDC.Width, SrcDC.Height, SrcDC.hDC, 0, 0, vbSrcCopy)

you will see that the return value is 0, which means fail.

Edit: try this

Option Explicit

Private History(255) As IPictureDisp
Private CurrentHistoryNumber As Long 

Function MakeHistoryPoint(ByVal HistoryReason As String)
     If CurrentHistoryNumber < 256 Then
        Set History(CurrentHistoryNumber&) = picImage.Image
        CurrentHistoryNumber = CurrentHistoryNumber + 1
        lstHistory.AddItem HistoryReason
    End If
End Function

[Edgemeal]

edit: removed

[XRsTX]

Thanks Milk it works somewhat, ..when I load different images it shows it in picSnapshot, but once i draw on the Image in picImage it adds itself to history, but then once i lift up (at the point when u let go and stop drawing it saves another history point) it changes with all the previous pictures; each of history points have all the drawing I added (except when i loaded the image), why is it doing this? I followed your above example exactly

[Milk]

Oops, I was hasty when I posted it, change the

Private History(255) As IPictureDisp

to (what you had)

Private History(255) As New StdPicture

Then the last image saved will be independent of the last History point.

If your still having problems post more code.

One thing though, if say you image was a modest 256×256 pixels and your display Properties were set to 24bit, History() is potentially going to hog 48MB. At 512×512 it could hog 192MB. Are you aware of this? It would be a lot more complected but you would be possibly better off 'remembering' a rectangle covering the changed area, not the whole image.

[XRsTX]

Yeah i'm aware that of it, they will be able to customize to how big they want it, and etc..., It's still not working though, the history picture is still the same. This is my code:

  Private History(255) As New StdPicture
  Private CurrentHistoryNumber As Long 'what history point we are at.

Private Sub picImage_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
 Select Case PreviousIndexCommonTools&
  Case 1 'Pen Tool
   If Button = vbLeftButton Then
     MakeHistoryPoint "iMage - Pen tool used"
    ElseIf Button = vbRightButton Then
     MakeHistoryPoint "iMage - Pen tool used"
   End If
 End Select
End Sub

Private Sub doPicStuff()
 If FileExists(lstAlbumPath.List(lstAlbum.ListIndex)) = True Then
  fraImg.Visible = True
   picImage.Picture = LoadPicture(lstAlbumPath.List(lstAlbum.ListIndex))
    MakeHistoryPoint "iMage loaded (" & lstAlbum.List(lstAlbum.ListIndex) & ")"
 End If

Function MakeHistoryPoint(ByVal HistoryReason As String)
 If CurrentHistoryNumber < 256 Then
  Set History(CurrentHistoryNumber&) = picImage.Image
   CurrentHistoryNumber = CurrentHistoryNumber + 1
  lstHistory.AddItem HistoryReason
 End If
End Function
End Sub

Private Sub lstHistory_Click() 'show image 
   picSnapshot.Picture = History(lstHistory.ListIndex)
End Sub

[Milk]

try

Private Sub lstHistory_Click() 'show image 
   set picSnapshot.Picture = History(lstHistory.ListIndex)
End Sub

I'm really rusty with VB's native graphics methods

[Edgemeal]

Yeah i'm aware that of it, they will be able to customize to how big they want it, and etc..., It's still not working though, the history picture is still the same.

Ya that is strange, I can't seem to see why picImage doesn't change to the selected history, but if I do this then it works!

Private Sub MakeHistoryPoint(ByVal HistoryReason As String)
    Set History(CurrentHistoryNumber) = picImage.Image
    lstHistory.AddItem HistoryReason
    lstHistory.Selected(CurrentHistoryNumber) = True
    CurrentHistoryNumber = CurrentHistoryNumber + 1
End Sub

Private Sub lstHistory_Click()
   Set History(255) = picImage.Image ' just tp preserve current image
   Set picImage.Picture = History(lstHistory.ListIndex)
   Set picSnapshot.Picture = History(lstHistory.ListIndex)
   Set picImage.Picture = History(255) ' restore preserved image
End Sub

[XRsTX]

Yeah I don't know either, I thought that what Milk had was correct cause I remember doing something like that before (i'm kinda rusty, haven't VB'd in awhile), but for some reason yeah Edgemeal that works perfectly...except I modify it a bit, but thanks for all the help.

[Edgemeal]

except I modify it a bit, but thanks for all the help.

What did you modify, I'm curious now!