vb6.0如何获取程序窗口指定坐标的像素值

Question

vb6.0如何获取程序窗口指定坐标的像素值，即使程序窗口最小化，也将获取程序窗口指定坐标的像素值。而不是获取电脑桌面这个坐标的像素值。

Answer 1

基于new Bing的回答：

以下是获取程序窗口指定坐标的像素值的VB6.0代码：

声明API函数

Private Declare Function GetDC Lib "user32" (ByVal hwnd As Long) As Long
Private Declare Function ReleaseDC Lib "user32" (ByVal hwnd As Long, ByVal hdc As Long) As Long
Private Declare Function GetPixel Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long) As Long

获取程序窗口的句柄

Dim hwnd As Long
hwnd = FindWindow(vbNullString, "程序窗口的标题")

获取程序窗口的设备上下文句柄

Dim hdc As Long
hdc = GetDC(hwnd)

获取指定坐标的像素值

Dim pixel As Long
pixel = GetPixel(hdc, x, y)

释放程序窗口的设备上下文句柄

ReleaseDC hwnd, hdc

完整代码如下：

Private Declare Function GetDC Lib "user32" (ByVal hwnd As Long) As Long
Private Declare Function ReleaseDC Lib "user32" (ByVal hwnd As Long, ByVal hdc As Long) As Long
Private Declare Function GetPixel Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long) As Long

Private Sub Command1_Click()
    Dim hwnd As Long
    hwnd = FindWindow(vbNullString, "程序窗口的标题")
    If hwnd = 0 Then
        MsgBox "未找到程序窗口"
        Exit Sub
    End If
    
    Dim hdc As Long
    hdc = GetDC(hwnd)
    
    Dim x As Long, y As Long
    x = 100
    y = 100
    Dim pixel As Long
    pixel = GetPixel(hdc, x, y)
    
    ReleaseDC hwnd, hdc
    
    MsgBox "像素值为：" & pixel
End Sub

需要注意的是，如果程序窗口最小化了，可以使用IsIconic函数来判断窗口是否最小化，如果最小化了，可以使用ShowWindow函数将窗口还原到正常状态