Question

以下代码适用于我正在做的事情。但是，它需要的时间比我需要的时间长。问题是它遍历每个大于/小于函数并且需要时间。我已经做了一些研究，但无法弄清楚如何减少它以便它运行得更快。

像素RGB值必须通过以下测试 - （1）如果一个值大于250，则其他值必须小于5 （2）如果一个值小于5，则其他值必须大于250 （3）如果一个值等于零，则其他值必须大于0 （4）任何2个值之间的差异必须小于15（或我设定的任何其他阈值）（5）看两个值是否等于零

另外，在这些功能有用之后会做'退出'吗？

    ' Create new bitmap from filepath in TextBox1
    Dim bmp As New Bitmap(TextBox1.Text)

    ' Lock the bitmap's pixels
    Dim rect As New Rectangle(0, 0, bmp.Width, bmp.Height)
    Dim bmpData As System.Drawing.Imaging.BitmapData = bmp.LockBits(rect, _
            Drawing.Imaging.ImageLockMode.ReadWrite, _
            Imaging.PixelFormat.Format24bppRgb)

    ' Get the address of the first line
    Dim ptr As IntPtr = bmpData.Scan0

    ' Declare an array to hold the bytes of the bitmap
    Dim bytes As Integer = Math.Abs(bmpData.Stride) * bmp.Height
    Dim rgbValues(bytes - 1) As Byte
    System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes)

    ' Retrieve RGB values
    Dim RedValue As Int32
    Dim GreenValue As Int32
    Dim BlueValue As Int32
    Dim l As Integer = 0                   
    For x = 0 To bmp.Width  
        For y = 0 To bmp.Height - 1
            l = ((bmp.Width * 3 * y) + (x * 3))
            RedValue = rgbValues(l)
            GreenValue = rgbValues(l + 1)
            BlueValue = rgbValues(l + 2)

            If RedValue < 5 AndAlso GreenValue < 5 AndAlso BlueValue > 250 Then
            ElseIf RedValue < 5 AndAlso GreenValue > 250 AndAlso BlueValue < 5 Then
            ElseIf RedValue > 250 AndAlso GreenValue < 5 AndAlso BlueValue < 5 Then
            ElseIf RedValue > 250 AndAlso GreenValue > 250 AndAlso BlueValue < 5 Then
            ElseIf RedValue > 250 AndAlso GreenValue < 5 AndAlso BlueValue > 250 Then
            ElseIf RedValue < 5 AndAlso GreenValue > 250 AndAlso BlueValue > 250 Then
            ElseIf RedValue > 0 AndAlso GreenValue > 0 AndAlso BlueValue.Equals(0) Then
            ElseIf RedValue > 0 AndAlso GreenValue.Equals(0) AndAlso BlueValue > 0 Then
            ElseIf RedValue.Equals(0) AndAlso GreenValue > 0 AndAlso BlueValue > 0 Then
            ElseIf (RedValue - GreenValue) < 15 AndAlso (RedValue - BlueValue) < 15 AndAlso _
                (GreenValue - RedValue) < 15 AndAlso (GreenValue - BlueValue) < 15 AndAlso _
                (BlueValue - RedValue) < 15 AndAlso (BlueValue - GreenValue) < 15 Then
            ElseIf RedValue.Equals(GreenValue) Then
            ElseIf RedValue.Equals(BlueValue) Then
            ElseIf GreenValue.Equals(BlueValue) Then
            ElseIf RedValue.Equals(BlueValue) AndAlso RedValue.Equals(GreenValue) _
                AndAlso BlueValue.Equals(GreenValue) Then
            Else
                MsgBox("Image is color.")
                Exit Sub
            End If
        Next
    Next
    MsgBox("Image is grayscale.")

    ' Unlock the bitmap
    bmp.UnlockBits(bmpData)

Answer 1

灰度颜色始终为此规格（R = G = B）。例如。 #cccccc = [R：204 G：204 B：204]

If Not R = G And G = B Then
 MsgBox("colored")
 Exit Sub
End If

VB.Net - Lockbits - 大于/小于函数

1 个答案: