Create "layers" like Photoshop/Paint shop pro **resolved**

[WALDO]

OK. I got a webcam program that I'm writing. I got everything I need including the camera capture, and the upload portion. I just want to do one thing.

I want to add a watermark based on an image and a position that the user specifies. I have the underlying image on a picturebox and I want to put the watermark image overtop of it like another layer, then add it to the picture property.

Anybody have any good methods of doing this?

[golgo13sf]

look up the BitBlt function in the search box. look up the raster op codes also for it, i forget which ones will give you that transparent watermark effect

[WALDO]

hdcWatermark = LoadImage(0, strPath, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE)
 
    lResult = BitBlt(frmCapture.Picture1.hdc, 0, 0, _
        96 * 15, _
        11 * 15, _
        hdcWatermark, 0, 0, vbSrcCopy)

No effect

[Sastraxi]

* 15 is for..? BitBlt uses pixels, so you needn't worry about Twips. And, SrcCopy will give you a big ol' rectangle around the image...

[Zaei]

LoadImage doesnt reaturn an HDC.

Z.

[Sastraxi]

Create a DC with CreateCompatibleDC, and use SelectObject to select the bitmap you get from LoadImage into it.

[WALDO]

Originally posted by Sastraxi
Create a DC with CreateCompatibleDC, and use SelectObject to select the bitmap you get from LoadImage into it.

lResult = LoadImage(0, strPath, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE)
    hdcWatermark = CreateCompatibleDC(0)
    Call SelectObject(hdcWatermark, lResult)
 
lResult = BitBlt(frmCapture.Picture1.hdc, 0, 0, _
        96 * 15, _
        11 * 15, _
        hdcWatermark, 0, 0, vbSrcCopy)

[joey o.]

don't forget to delete the object or you'll crash after about 15-20 iterations depending on your memory. This code might help you delete it properly:

Dim hMemDC As Long
Dim hOldBMP As Long

' Create memory DC
hMemDC = CreateCompatibleDC(Me.hdc)

' Select bitmap into it, storing the previous value
' (SelectObject returns the previous bitmap which
' was selected into the DC)
hOldBMP = SelectObject(hMemDC, CreateCompatibleBitmap(Me.hdc, Width, Height))

'
' Now you can draw...
'

' First, select the old bitmap back into the DC and delete our bitmap
DeleteObject(SelectObject(hMemDC, hOldBMP))

' Now delete the DC
DeleteDC(hMemDC)

[WALDO]

good to know