5. Projects using Intrinsic and Professional ActiveX Controls

4. Project for displaying color gradient:

The program shown in the figure 7a is intended to display a gradient of colors in a picture box. The design window consists of one picture box and a command button as shown in the figure 7.  On executing this program you will find a color gradient filling the picture box as shown in the figure 8.   You can try with different starting and ending colors by changing the RGB values.

              Figure 7

Private Sub Command1_Click()

Dim newcolor As Long

Dim ipixel, pwidth As Integer

Dim redinc, greeninc, blueinc As Single

Dim color1 As Long, color2 As Long

color1 = RGB(255, 255, 0)

color2 = RGB(0, 0, 0)

startred = getred(color1)

endred = getred(color2)

startgreen = getgreen(color1)

endgreen = getgreen(color2)

startblue = getblue(color1)

endblue = getblue(color2)

pwidth = Picture1.ScaleWidth

redinc = (endred - startred) / pwidth

greeninc = (endgreen - startgreen) / pwidth

blueinc = (endblue - startblue) / pwidth

For ipixel = 0 To pwidth - 1

newcolor = RGB(startred + redinc * ipixel, startgreen + greeninc * ipixel, startblue + blueinc * ipixel)

Picture1.Line (ipixel, 0)-(ipixel, Picture1.Height - 1), newcolor

Next

End Sub

Function getred(colorval As Long) As Integer

getred = colorval Mod 256

End Function

Function getgreen(colorval As Long) As Integer

tgreen = ((colorval And &HFF00FF) / 256&)

End Function

Function getblue(colorval As Long) As Integer

getblue = (colorval And &HFF0000) / (256& * 256&)

End Function

                Figure 7a

 
                           Figure 8