efficiency! where are you!

[MrPolite]

I tried to make a "simple" test program that copies a picture from a picturebox to another picturebox, pixel by pixel. But that takes a while, even though I'm not doing any kind of process on the image.
Can you guys please download the program that I made and take a look at it and see how can I make it faster? I'm sure it should be easy...
(This is a test program, I know how to copy a picture from a picturebox to another, I just need help on the speed of the process )
tnx for the help

[MidgetsBro]

SetPixelV is supposed to be faster, but I didn't see any difference in speed when I tried it. Can't you just BitBlt the whole image at once, and it will go a lot faster? Look what I did to the project and you see if you can do this.

[MrPolite]

thanks for the help, but SetpixelV is slower. I dont want to use bitblt because I want to add effects to the picture (this is just a sample to test the speed first.)
still looking for it

[MidgetsBro]

I don't think you are going to get any faster without using somthing other than setpixel. I don't know of any other way to do it though. What if you bitblt the image, and then use setpixel to change only pixels that you want to add the effects to? I don't know how to do that, but it sounds like it would work in theory. (And everything works in theory )

[MrPolite]

hehehe, I hope it was that easy
what if I want to edit all the pixels!!?!!!

[MidgetsBro]

If you want to edit all the pixels, then your SOL (***** Outta Luck) . You will just have to deal with the slow .8 seconds it takes to do that. What's wrong with .8 seconds anyway?

[Joacim Andersson]

Looping through all the pixels in a picture box will be slow.
However I made a few changes to the code that makes it slighter faster.
I simply added more variables so you don't read property values more then once.
Checking the property value of an object is slower then using a variable.
You're also loop to picSrc.ScaleWidth and picSrc.ScaleHeight but it should be one less since the first pixel is at position 0,0 and not 1,1.

Private Sub cmdStart_Click()
    Dim x As Long, y As Long
    Dim startTime As Long
    Dim lngColor As Long
    Dim nSW As Long, nSH As Long
    Dim hSrcDC As Long, hDestDC As Long
    
    Dim blnRefresh As Boolean
    picDest.Cls
    hSrcDC = picSrc.hdc
    hDestDC = picDest.hdc
    blnRefresh = (chkRefresh.Value = vbChecked)
    nSW = picSrc.ScaleWidth - 1 'don't loop longer then necassary
    nSH = picSrc.ScaleHeight - 1
    lblStatus.Caption = "Processing..."
    lblStatus.Refresh
    startTime = GetTickCount()
    For x = 0 To nSW
        For y = 0 To nSH
            lngColor = GetPixel(hSrcDC, x, y)
            SetPixel hDestDC, x, y, lngColor
        Next y
                
        If blnRefresh = True And x Mod 5 = 0 Then
            picDest.Refresh
        End If
    Next x
 
    lblStatus.Caption = "Done in " & (GetTickCount() - startTime) / 1000 & " seconds"
    picDest.Refresh
End Sub

Best regards

[MrPolite]

hehehe, I never realized that those factors make the code slower... thanks alot
But there should be a faster way though

[MrPolite]

I'm still looking for a solution, please help!