我已将此代码翻译成 VB.NET，这是一个检查图像是否为灰度的函数。
private static unsafe bool IsGrayScale(Image image)
{
using (var bmp = new Bitmap(image.Width, image.Height, PixelFormat.Format32bppArgb))
{
using (var g = Graphics.FromImage(bmp))
{
g.DrawImage(image, 0, 0);
}
var data = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadOnly, bmp.PixelFormat);
var pt = (int*)data.Scan0;
var res = true;
for (var i = 0; i < data.Height * data.Width; i++)
{
var color = Color.FromArgb(pt[i]);
if (color.A != 0 && (color.R != color.G || color.G != color.B))
{
res = false;
break;
}
}
bmp.UnlockBits(data);
return res;
}
}
C# 代码正在工作，但没有做我需要的工作，所以我做了一些修改，试图制作一个检查图像是否具有某种 RGB 颜色但最重要的部分不起作用的函数：
Dim color__1 = Color.FromArgb(pt(i))
例外：
Error 1 Expression is not an array or a method, and cannot have an argument list. C:\Visual Studio Projects\WindowsApplication9\WindowsApplication9\Form1.vb 21 47 WindowsApplication9
这是翻译后的代码：
Imports System.Drawing.Imaging
Public Class Form1
Private Shared Function ImageHasColor(ByVal image As Image, ByVal R As Int32, ByVal G As Int32, ByVal B As Int32) As Boolean
Using bmp = New Bitmap(image.Width, image.Height, PixelFormat.Format32bppArgb)
Using graph = Graphics.FromImage(bmp)
graph.DrawImage(image, 0, 0)
End Using
Dim data = bmp.LockBits(New Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.[ReadOnly], bmp.PixelFormat)
Dim pt = CType(data.Scan0, Integer)
MsgBox(pt)
Dim res As Boolean
Dim i = 0
While i < data.Height * data.Width
Dim color__1 = Color.FromArgb(pt(i))
If color__1.A <> 0 AndAlso color__1.R = R AndAlso color__1.G = G AndAlso color__1.B = B Then
res = True
Exit While
End If
System.Math.Max(System.Threading.Interlocked.Increment(i), i - 1)
End While
bmp.UnlockBits(data)
Return res
End Using
End Function
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim bmp = New Bitmap("C:\Users\Administrador\Desktop\PrtScr capture_3.jpg")
MsgBox(ImageHasColor(bmp, 240, 240, 240))
End Sub
End Class
更新：
这些代码仅适用于第一次，如果我多次使用它，我会收到此错误：
尝试读取或写入受保护的内存
1.
Private Shared Function ImageHasColor(ByVal image As Image, ByVal R As Int32, ByVal G As Int32, ByVal B As Int32) As Boolean
Using bmp = New Bitmap(image.Width, image.Height, PixelFormat.Format32bppArgb)
Using graph = Graphics.FromImage(bmp)
graph.DrawImage(image, 0, 0)
End Using
Dim color__1 As Color
Dim byt
Dim data = bmp.LockBits(New Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.[ReadOnly], bmp.PixelFormat)
Dim pt = CType(data.Scan0, Integer)
Dim res As Boolean
For i = 0 To data.Height * data.Width - 1
color__1 = Color.FromArgb(Marshal.ReadInt32(pt, i * 4))
If color__1.A <> 0 AndAlso color__1.R = R AndAlso color__1.G = G AndAlso color__1.B = B Then
res = True
Exit For
End If
'System.Math.Max(System.Threading.Interlocked.Increment(i), i - 1)
Next
bmp.UnlockBits(data)
Return res
End Using
End Function
2.
Private Shared Function ImageHasColor(ByVal image As Image, ByVal R As Int32, ByVal G As Int32, ByVal B As Int32) As Boolean
Using bmp = New Bitmap(image.Width, image.Height, PixelFormat.Format32bppArgb)
Using graph = Graphics.FromImage(bmp)
graph.DrawImage(image, 0, 0)
End Using
Dim color__1 As Color
Dim byt
Dim data = bmp.LockBits(New Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.[ReadOnly], bmp.PixelFormat)
Dim pt = CType(data.Scan0, Integer)
Dim res As Boolean
Dim i = 0
While i < data.Height * data.Width
color__1 = Color.FromArgb(Marshal.ReadInt32(pt, i * 4))
If color__1.A <> 0 AndAlso color__1.R = R AndAlso color__1.G = G AndAlso color__1.B = B Then
res = True
Exit While
End If
System.Math.Max(System.Threading.Interlocked.Increment(i), i - 1)
End While
bmp.UnlockBits(data)
Return res
End Using
End Function
更新：
这段代码似乎工作
Private Shared Function ImageHasColor(ByVal image As Image, ByVal R As Int32, ByVal G As Int32, ByVal B As Int32) As Boolean
Try
Using bmp = New Bitmap(image.Width, image.Height, PixelFormat.Format32bppArgb)
Using graph = Graphics.FromImage(bmp) : graph.DrawImage(image, 0, 0) : End Using
Dim Pixel_Color As Color
Dim Ditmap_Data = bmp.LockBits(New Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.[ReadOnly], bmp.PixelFormat)
Dim pt As IntPtr = CType(Ditmap_Data.Scan0, IntPtr)
For i = 0 To Ditmap_Data.Height * Ditmap_Data.Width - 1
Pixel_Color = Color.FromArgb(Marshal.ReadInt32(pt, i * 4))
If Pixel_Color.A <> 0 AndAlso Pixel_Color.R = R AndAlso Pixel_Color.G = G AndAlso Pixel_Color.B = B Then
bmp.UnlockBits(Ditmap_Data)
Return True
End If
Next
bmp.UnlockBits(Ditmap_Data)
Return False
End Using
Catch ex As Exception
MsgBox(ex.Message)
Return Nothing
End Try
End Function