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Faded Background with API

Posted: 2019-09-19
By: AndreaTincani
Viewed: 170

Filed Under:

VB6 Custom Controls/Forms/Menus, VB6 Windows API, VB6 Code Cache

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This handy little chunk of code will show you how to create a faded background on a form, using the Windows API.

Option Explicit

' Data type used by FillRect
   Left As Long
   Top As Long
   Right As Long
   Bottom As Long
End Type

' API Functions used to create solid brush and draw brush on form
Public Declare Function CreateSolidBrush Lib "gdi32.dll" (ByVal crColor As Long) As Long
Public Declare Function FillRect Lib "user32.dll" (ByVal hdc As Long, lpRect As RECT, ByVal hBrush As Long) As Long
Public Declare Function DeleteObject Lib "gdi32.dll" (ByVal hObject As Long) As Long

Public Sub FadeForm(frm As Form, colStart As Long, colEnd As Long)
   Dim red As Single
   Dim green As Single
   Dim blue As Single
   Dim redStep As Single
   Dim greenStep As Single
   Dim blueStep As Single
   Dim StepInterval As Single
   Dim X As Long
   Dim ret As Long
   Dim OldMode As Long
   Dim FillArea As RECT
   Dim rTop As Single
   Dim hBrush As Long

   ' retrive the old scale mode of the form
   OldMode = frm.ScaleMode
   ' set the Scale Mode of the form to Pixels
   frm.ScaleMode = vbPixels
   ' calculate the vertical step and the colors step
   StepInterval = frm.ScaleHeight / 64
   blue = (colStart \ &H10000) And &HFF
   blueStep = (blue - ((colEnd \ &H10000) And &HFF)) / 64
   green = (colStart \ &H100) And &HFF
   greenStep = (green - ((colEnd \ &H100) And &HFF)) / 64
   red = (colStart And &HFF)
   redStep = (red - (colEnd And &HFF)) / 64
   rTop = 0
   FillArea.Left = 0
   FillArea.Right = frm.ScaleWidth
   FillArea.Top = 0
   FillArea.Bottom = StepInterval
   ' paint the form with a gradient brush
   For X = 1 To 64
      hBrush = CreateSolidBrush(RGB(red, green, blue))
      ret = FillRect(frm.hdc, FillArea, hBrush)
      ret = DeleteObject(hBrush)
      red = red - redStep
      green = green - greenStep
      blue = blue - blueStep
      rTop = rTop + StepInterval
      FillArea.Top = rTop
      FillArea.Bottom = rTop + StepInterval
End Sub


Create a Form and add the following code in the Paint and Resize events

Private Sub Form_Paint()
   ' Paint the Form's Background starting with Blue on top and fading to black
   FadeForm Me, RGB(0, 0, 255), RGB(0, 0, 0)
End Sub

Private Sub Form_Resize()
   ' Do the same on the resize event
   FadeForm Me, RGB(0, 0, 255), RGB(0, 0, 0)
End Sub

Special Instructions

This code originally appeared on, and has been republished here with the permission of Andrea Tincani.

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