Question

VB如何实现不规则窗体

在窗体中放入一个pictures，图片背景是RGB 255,0,0也就是红色的，要把图片的背景过滤掉，使窗体成为一个不规则窗体，如何实现？

Answer 1

'要用两个API
SetLayeredWindowAttributes的功能：

'其中hwnd是透明窗体的句柄，crKey为颜色值，bAlpha是透明度，取值范围是[0,255]，当小于5时，

'鼠标通信透明，大于或等于5时鼠标不透明，dwFlags是透明方式，可以取两个值：当取值为 &H2 时，

'crKey参数无效，bAlpha参数有效；当取值为 &H1 时，bAlpha参数有效而窗体中的所有颜色为crKey

'的地方将变为透明－－这个功能很有用：我们不必再为建立不规则形状的窗体而调用一大堆区域分析、

'创建、合并函数了，只需指定透明处的颜色值即可，哈哈哈哈！请看具体代码。

'代码:
一个部分透明窗体
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function SetLayeredWindowAttributes Lib "user32" (ByVal hwnd As Long, ByVal crKey As Long, ByVal bAlpha As Byte, ByVal dwFlags As Long) As Long

Private Sub Form_Load()

SetWindowLong hwnd, (-20), &H80000

SetLayeredWindowAttributes Me.hwnd, vbRed, 5, &H1
End Sub

Answer 2

Private Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long Private Declare Function SetLayeredWindowAttributes Lib "user32" (ByVal hwnd As Long, ByVal crKey As Long, ByVal bAlpha As Byte, ByVal dwFlags As Long) As Long
Private Const WS_EX_LAYERED = &H80000 Private Const GWL_EXSTYLE = (-20) Private Const LWA_ALPHA = &H2 Private Const LWA_COLORKEY = &H1 Private Sub Form_Load() 　　Dim rtn As Long 　　rtn = GetWindowLong(hwnd, GWL_EXSTYLE) 　　rtn = rtn Or WS_EX_LAYERED 　　SetWindowLong hwnd, GWL_EXSTYLE, rtn 　　SetLayeredWindowAttributes hwnd, RGB(255, 0, 0), 0, LWA_ALPHA Or LWA_COLORKEYEnd Sub 去除窗体内所有RGB(255, 0, 0)的颜色.