如何使用vb.net获取X，Y处的像素颜色

Question

嘿，我可以通过设置像素属性设置图像的颜色，但是当我把条件设置为getPixel时，没有错误发生但程序卡住了

我把下面的代码请检查它给我解决方案：

    Dim b As Bitmap = New Bitmap("D:\test.bmp")

' Make Image Indexed

        Dim nii As New Bitmap(b.Width, b.Height,
System.Drawing.Imaging.PixelFormat.Format32bppPArgb)
        For y As Integer = 0 To nii.Height - 1
            For x = 0 To nii.Width - 1
                Dim cw As New Color
                cw = Color.Black
                If nii.GetPixel(x, y) = cw Then
                    nii.SetPixel(x, y, Red)
                End If

            Next
        Next
        PictureBox1.Image = FromFile("D:\test.bmp")
        PictureBox2.Image = nii

如果我删除了getPixel，那么程序可以正常工作，但是完整的图像颜色会变成红色。

Answer 1

您需要比较颜色的ARGB值

Dim cw As New Color
cw = Color.Black
dim curPixColor as Color = b.GetPixel(x, y)
If curPixColor.ToArgb = cw.ToArgb Then
    nii.SetPixel(x, y, Color.Red)
End If

或者你应该使用Equality Operator

Dim cw As New Color
cw = Color.Black
dim curPixColor as Color = b.GetPixel(x, y)
If Color.op_Equality(curPixColor, cw) Then
    nii.SetPixel(x, y, Color.Red)
End If

参考：http://msdn.microsoft.com/en-us/library/system.drawing.color.op_equality(v=vs.110).aspx

编辑： 当您从bmp获取像素时，不支持透明度。所以你的比较颜色应该是

cw = Color.FromArgb(0,0,0,0)

<强> EDIT2 ： 你正在阅读来自nii的像素，你应该从b

阅读

dim curPixColor as Color = b.GetPixel(x, y)

完整代码应该是（测试的）

    Dim b As Bitmap = New Bitmap("D:\test.bmp")

    ' Make Image Indexed

    Dim nii As New Bitmap(b.Width, b.Height, System.Drawing.Imaging.PixelFormat.Format32bppPArgb)
    For y As Integer = 0 To nii.Height - 1
        For x = 0 To nii.Width - 1
            Dim cw As New Color
            cw = Color.Black
            Dim curPixColor As Color = b.GetPixel(x, y)
            If curPixColor.ToArgb() = cw.ToArgb() Then
                nii.SetPixel(x, y, Color.Red)
            Else
                nii.SetPixel(x, y, curPixColor)
            End If
        Next
    Next
    PictureBox1.Image = Image.FromFile("D:\test.bmp")
    PictureBox2.Image = nii

Answer 2

我有一个类似的问题，但是比较RGB值是可行的。谢谢！

实际上，您可以执行以下操作，而不是过多变量：

If b.GetPixel(x,y).ToArgb() = Color.Black.ToArgb() then......