Fading form BackColor?

Hi, I'm using this code to fade the BackColor of my form:

    'Declares variables for the fader
    Dim Red As Integer
    Dim Green As Integer
    Dim Blue As Integer
    Dim i As Integer
    
    'Colors to fade to/from
    For Red% = 0 To 12 Step 1
    For Green% = 0 To 0
    For Blue% = 0 To 246 Step 1
        'how to fade
        Form1.BackColor = RGB(Red%, Green%, Blue%)
    For i = 1 To 31999
    tmrFader.Enabled = False
    Next
    Next
    Next
    Next

Now, this code works as I want it to, but its incredibly unstable. I'm using Win2K and VB6(No SP), and this little application crashes all the time. Does anybody see if I've done anything that I shouldn't have? Or maybe somebody can recommend a better way to do this.

[Jotaf98]

Hum... first thing is, I don't understand the point of these 3 lines:

    For i = 1 To 31999
    tmrFader.Enabled = False
    Next

Otherwise I don't see anything wrong, except for the useless loop for the Green that is always 0

I intend to use this code for more than one fade, thats why I have the Green loop. The For i = 1 To 31999 Is to delay the fading a bit (31999 was the highest number I could use without causing an error, don't ask me why). And I need the tmrFader.Enabled = False to show only one fade instead of three (I have no idea why but thats the way it is). And the Next is obviously there because of the For i =...

[Jotaf98]

The error in your code is that it will loop 12 times incrementing Red by one each time and inside each of these it will loop 246 times incrementing Blue each time...

This is a modified version of your code. Remember, it uses only one loop:

Private Sub Form_Click()
    'Declare variables for the fader
    Dim i As Long
    
    'This is the final color's RGB!
    Const R = 255
    Const G = 128
    Const B = 64
    
    For i = 0 To 255
        'How to fade
        Form1.BackColor = RGB(R * i \ 256, G * i \ 256, B * i \ 256)
        
        'So the loop is interruptible and you can
        'click Close and other things
        DoEvents
    Next
End Sub

Modify the color, click the form and see it all happen

[Jotaf98]

The other loop you used (0 to 31999 or something) will not work well because it will run very slow in a slow computer and very fast in a fast computer... forgot to tell you. Try a Timer instead: declare "i" using Static instead of Dim (so it is still there even when you get out of the sub), remove the loop and put it in the timer's sub.

[YoungBuck]

Here is a function that a created to fade a form (or any object that has a BackColor property) a while back that you can use if you want to....

In a module

Option Explicit

Private Type RGBColor
    R As Long
    G As Long
    B  As Long
 End Type

Public Sub FadeForm(pCtl As Object, pStartCol As Long, pEndCol As Long, pLoopCt As Long)
 Dim rgbS As RGBColor
 Dim rgbE As RGBColor
 Dim iRChg As Single, iGChg As Single, iBChg As Single
 Dim lCurColor As Long
 Dim iCt As Integer
 
 ' Retrieve the individual red, green, and blue values for the start color
 rgbS = IndColors(pStartCol)
 
 ' Retrieve the individual red, green, and blue values for the start color
 rgbE = IndColors(pEndCol)
 
 ' Get the amount to change the colors during the loop
 iRChg = (rgbE.R - rgbS.R) / pLoopCt
 iGChg = (rgbE.G - rgbS.G) / pLoopCt
 iBChg = (rgbE.B - rgbS.B) / pLoopCt
 
 For iCt = 1 To pLoopCt
    
    'get the value of the current color
    lCurColor = RGB(rgbS.R + iRChg * iCt, rgbS.G + iGChg * iCt, rgbS.B + iBChg * iCt)
    
    'display the  current color of the form
    pCtl.BackColor = lCurColor
    
    'allow other processes to execute
    DoEvents
    
 Next iCt
 
End Sub

Private Function IndColors(pCol As Long) As RGBColor

With IndColors

    .B = pCol \ 65536
    .G = (pCol - .B * 65536) \ 256
    .R = pCol - .B * 65536 - .G * 256
    
End With

End Function

And put this code in a form

Option Explicit

Private Sub Form_Load()
    
    Me.Show
    
    ' Fade a form from Blue to Green, run the coloring loop 10000 times
    FadeForm Me, vbBlue, vbGreen, 10000
    
End Sub

If the sub is fading to quickly just increase the value of the pLoopCt parameter higher than 10000 to make the fading effect slow down, or if you want it to fade faster decrease the pLoopCt parameter. Enjoy!

'Ello, thanks for the code, now my computer has stopped crashing . I used your code, Jotaf (didn't understand much of YoungBucks..). But what was it you said I should do if I wanted to delay the fade? Didn't understand what you wanted me to do... Mind telling me?

[schnarf283]

You can use the sleep API command to make it pause.

[Jotaf98]

YoundBuck's code is good, it allows you to fade not only from black to a color, but from any two colors! Try to study it a bit more

This code assumes the timer's name is "Timer1":

Private Sub Timer1_Timer()
    'Declare variables for the fader
    Static i As Long
    
    'This is the final color's RGB!
    Const R = 255
    Const G = 128
    Const B = 64
    
    If i < 255 Then
        'How to fade
        Form1.BackColor = RGB(R * i \ 256, G * i \ 256, B * i \ 256)
        
        'NOTE: I removed DoEvents because now the
        'events happen between each Timer event ;)
        
        'Increase the count
        i = i + 1
    Else
        '"i" is bigger than 255, so stop
        Timer1.Enabled = False
    End If
End Sub

Hope that helped