Public Sub DoRotate(Optional ByVal RotaryAngle As Long = 0) ‘任意角度旋转
Dim sDIB As New cDIB
Dim sBits() As RGBQUAD
Dim dBits() As RGBQUAD
Dim stSA As SAFEARRAY2D
Dim dtSA As SAFEARRAY2D
Dim Lev As Long
Dim Wgt As Long
Dim x As Long
Dim y As Long
Dim newW As Long, W As Long
Dim newH As Long, H As Long
Dim f1 As Double, f2 As Double
If (m_hDIB <> 0) Then
‘+++++++++++++++
Dim OldWidth, OldHeight As Integer
Dim NewWidth, NewHeight As Integer
Dim Theta As Double
Dim dx, dy As Single
Dim dxx, dyy As Integer
Dim rx0, ry0 As Double
‘ 源图四个角的坐标（以图像中心为坐标系原点）
Dim SrcX1, SrcY1, SrcX2, SrcY2, SrcX3, SrcY3, SrcX4, SrcY4, ThetaCos, ThetaSin As Double
OldWidth = m_tBIH.biWidth - 1
OldHeight = m_tBIH.biHeight - 1
SrcX1 = -(OldWidth - 1) / 2
SrcY1 = (OldHeight - 1) / 2
SrcX2 = (OldWidth - 1) / 2
SrcY2 = (OldHeight - 1) / 2
SrcX3 = -(OldWidth - 1) / 2
SrcY3 = -(OldHeight - 1) / 2
SrcX4 = (OldWidth - 1) / 2
SrcY4 = -(OldHeight - 1) / 2
Theta = RotaryAngle / 180 * 3.141592653
ThetaCos = Cos(Theta)
ThetaSin = Sin(Theta)
‘// 旋转后四个角的坐标（以图像中心为坐标系原点）
Dim DstX1, DstY1, DstX2, DstY2, DstX3, DstY3, DstX4, DstY4 As Double
DstX1 = Cos(Theta) * SrcX1 + Sin(Theta) * SrcY1
DstY1 = -Sin(Theta) * SrcX1 + Cos(Theta) * SrcY1
DstX2 = Cos(Theta) * SrcX2 + Sin(Theta) * SrcY2
DstY2 = -Sin(Theta) * SrcX2 + Cos(Theta) * SrcY2
DstX3 = Cos(Theta) * SrcX3 + Sin(Theta) * SrcY3
DstY3 = -Sin(Theta) * SrcX3 + Cos(Theta) * SrcY3
DstX4 = Cos(Theta) * SrcX4 + Sin(Theta) * SrcY4
DstY4 = -Sin(Theta) * SrcX4 + Cos(Theta) * SrcY4
NewWidth = IIf(Abs(DstX4 - DstX1) > Abs(DstX3 - DstX2), Abs(DstX4 - DstX1), Abs(DstX3 - DstX2)) + 0.5 ‘+ 50
NewHeight = IIf(Abs(DstY4 - DstY1) > Abs(DstY3 - DstY2), Abs(DstY4 - DstY1), Abs(DstY3 - DstY2)) + 0.5 ‘+ 50
rx0 = OldWidth * 0.5 ‘(rx0,ry0)为旋转中心
ry0 = OldHeight * 0.5
f1 = -0.5 * (NewWidth - 1) * ThetaCos + 0.5 * (NewHeight - 1) * ThetaSin + 0.5 * (OldWidth - 1)
f2 = -0.5 * (NewWidth - 1) * ThetaSin - 0.5 * (NewHeight - 1) * ThetaCos + 0.5 * (OldHeight - 1)
‘+++++++++++++++
‘-- Get source Bits
Call sDIB.Create(m_tBIH.biWidth, m_tBIH.biHeight)
Call sDIB.LoadBlt(m_hDC)
Call pvBuildSA(stSA, sDIB)
Call CopyMemory(ByVal VarPtrArray(sBits()), VarPtr(stSA), 4)
‘-- Create new DIB
Call Create(NewWidth, NewHeight)
Call pvBuildSA(dtSA, Me)
Call CopyMemory(ByVal VarPtrArray(dBits()), VarPtr(dtSA), 4)
W = NewWidth
H = NewHeight
For y = 1 To H - 1
For x = 1 To W - 1
With dBits(x, y)
dxx = CInt(x * ThetaCos - y * ThetaSin + f1 + 0.5)
dyy = CInt(x * ThetaSin + y * ThetaCos + f2 + 0.5)
If dxx > 0 And dyy > 0 And dxx < OldWidth And dyy < OldHeight Then
.B = sBits(dxx, dyy).B
.G = sBits(dxx, dyy).G
.R = sBits(dxx, dyy).R
Else
.B = 0
.G = 0
.R = 0
End If
End With
Next x
RaiseEvent Progress(y)
Next y
Call CopyMemory(ByVal VarPtrArray(sBits), 0&, 4)
Call CopyMemory(ByVal VarPtrArray(dBits), 0&, 4)
RaiseEvent ProgressEnd
End If
End Sub
+++++++++++++++
Public Function Hungh(DIB As cDIB, Optional ByVal Level As Byte = 95) As Integer ‘二值化
Dim Bits() As RGBQUAD
Dim tSA As SAFEARRAY2D
Dim L As Byte
Dim npp(0 To 180, 0 To 1000) As Integer ‘hungh变换后数组
Dim maxA, kmax, pMax, mp, tempL As Integer ‘最大角度 180
Dim Radian As Double
Dim m, n, k As Integer
Dim p As Integer ‘hough变换中的距离参数
maxA = 180
kmax = 0 ‘记录最长直线的角度
pMax = 0 ‘记录最长直线的距离
Radian = 3.141592653 / 180
If (DIB.hDIB <> 0) Then
pvBuildSA tSA, DIB
CopyMemory ByVal VarPtrArray(Bits()), VarPtr(tSA), 4
W = DIB.Width - 1
H = DIB.Height - 1
mp = Sqr(W * W + H * H)
For y = 2 To H - 2
For x = 2 To W - 2
With Bits(x, y)
L = 0.114 * .B + 0.587 * .G + 0.299 * .R
If L = 0 Then
For k = 1 To maxA
p = CInt(x * Cos(Radian * k) + y * Sin(Radian * k)) ‘p hough变换中的距离参数
p = CInt(p / 2 + mp / 2) ‘对P值优化，防止为负值
‘If p < 0 Then Stop
npp(k, p) = npp(k, p) + 1 ‘npp对变换域中对应重复出现的点累加
Next k
End If
End With
Next x
RaiseEvent Progress(y)
Next y
For m = 1 To maxA ‘maxa=180
For n = 1 To mp ‘mp为原图对角线距离
If npp(m, n) > tempL Then
tempL = npp(m, n) ‘找出最长直线 tempL为中间变量用于比较
kmax = m ‘记录最长直线的角度
pMax = n ‘记录最长直线的距离
End If
Next n
Next m
For y = 2 To H - 2
For x = 2 To W - 2
With Bits(x, y)
L = 0.114 * .B + 0.587 * .G + 0.299 * .R
If L = 0 Then
p = CInt(x * Cos(Radian * kmax) + y * Sin(Radian * kmax)) ‘p hough变换中的距离参数
p = CInt(p / 2 + mp / 2) ‘对P值优化，防止为负值
If p = pMax Then
.G = 0
.B = 255
.R = 0
End If
End If
End With
Next x
RaiseEvent Progress(y)
Next y
Hungh = kmax - 90
‘MsgBox kmax - 90
Call CopyMemory(ByVal VarPtrArray(Bits), 0&, 4)
RaiseEvent ProgressEnd
End If
End Function
原文：http://www.cnblogs.com/dhaichen/p/5222074.html