Private Sub SetBrightness(ByVal pic1 As PictureBox, ByVal _
pic2 As PictureBox, ByVal brightness As Single)
Dim bitmap_info As BITMAPINFO
Dim pixels() As Byte
Dim bytes_per_scanLine As Integer
Dim pad_per_scanLine As Integer
Dim X As Integer
Dim Y As Integer
Dim fraction As Single
' Get the original picture's bits.
' Prepare the bitmap description.
With bitmap_info.bmiHeader
.biSize = 40
.biWidth = Picture1.ScaleWidth
' Use negative height to scan top-down.
.biHeight = -Picture1.ScaleHeight
.biPlanes = 1
.biBitCount = 32
.biCompression = BI_RGB
bytes_per_scanLine = ((((.biWidth * .biBitCount) + _
31) \ 32) * 4)
pad_per_scanLine = bytes_per_scanLine - (((.biWidth _
* .biBitCount) + 7) \ 8)
.biSizeImage = bytes_per_scanLine * Abs(.biHeight)
End With
' Load the bitmap's data.
ReDim pixels(1 To 4, 1 To Picture1.ScaleWidth, 1 To _
Picture1.ScaleHeight)
GetDIBits Picture1.hdc, Picture1.Image, _
0, Picture1.ScaleHeight, pixels(1, 1, 1), _
bitmap_info, DIB_RGB_COLORS
' Modify the pixels.
If brightness < 0 Then
' Darken.
fraction = (100 + brightness) / 100
For Y = 1 To pic1.ScaleHeight
For X = 1 To pic1.ScaleWidth
pixels(pixR, X, Y) = fraction * _
pixels(pixR, X, Y)
pixels(pixG, X, Y) = fraction * _
pixels(pixG, X, Y)
pixels(pixB, X, Y) = fraction * _
pixels(pixB, X, Y)
Next X
Next Y
Else
' Brighten.
fraction = brightness / 100
For Y = 1 To pic1.ScaleHeight
For X = 1 To pic1.ScaleWidth
pixels(pixR, X, Y) = pixels(pixR, X, Y) + _
fraction * (255 - pixels(pixR, X, Y))
pixels(pixG, X, Y) = pixels(pixG, X, Y) + _
fraction * (255 - pixels(pixG, X, Y))
pixels(pixB, X, Y) = pixels(pixB, X, Y) + _
fraction * (255 - pixels(pixB, X, Y))
Next X
Next Y
End If
' Display the result.
SetDIBits Picture2.hdc, Picture2.Image, _
0, Picture1.ScaleHeight, pixels(1, 1, 1), _
bitmap_info, DIB_RGB_COLORS
Picture2.Picture = Picture2.Image
End Sub
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