如何在VB中利用API使Form背景独自透明

[zhejiong]

这个问题我一直没有好的解决方法，用API实现VB程序窗口form透明是很容易的事情，但是同时会出现一个问题，即FORM上的button、picture、label也同时透明，我知道在VB.NET中可以通过设置参数使FORM中的某一种色彩透明，形成FORM背景单独透明的效果，但是在VB6中应该如何取实现呢？

注：不是指程序窗口透明，这个我懂

[麦田之兔]

想让button、label透明很简单，都用label设置label1.BackStyle =1
picture透明做什么，你让图片透明？不知道你的picture里放的是什么

[zhejiong]

楼上的误会了，我是要让form的背景透明，不是让button之类的透明，举个例子，我在form上放了个swf，并将swf设置为透明，但是后面还有一个form，如果我用API把form也设置为透明的，则form上的swf也会跟着一起透明，我现在需要的是让form看不见，但是form上的所有东西都能看见，这就是我说的form背景单独透明的意思。

[zdingyun]

代码来自VB编程技巧10000例(源江科技),供参考:

Option Explicit
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 SetParent Lib "user32" (ByVal hWndChild As Long, ByVal hWndNewParent As Long) As Long
Const GWL_EXSTYLE = (-20)
Const WS_EX_TRANSPARENT = &H20&
Dim sj As Boolean

Private Sub Command3_Click()
Form1.Show
End Sub

Private Sub Form_Activate()
SetWindowLong hwnd, GWL_EXSTYLE, WS_EX_TRANSPARENT
End Sub

Private Sub Form_Load()
SetWindowLong hwnd, GWL_EXSTYLE, WS_EX_TRANSPARENT
End Sub
Private Sub Command1_Click()
Print "Hello"
End Sub

Private Sub Command2_Click()
End
End Sub

Private Sub Form_Click()
If sj Then
Me.WindowState = 2
Else
Me.WindowState = 0
End If
sj = Not sj
End Sub

[麦田之兔]

楼上的用的Api是这些，就是思路不好。应该是从Form左上角开始到右下角。
遇到swf(应该是Flash控件吧)的地方就不处理其他地方都是透明。

[zdingyun]

Option Explicit
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
Const WS_EX_LAYERED = &H80000
Const GWL_EXSTYLE = (-20)
Const LWA_ALPHA = &H2
Const LWA_COLORKEY = &H1
Dim sty As Long
Dim cs As Integer

Private Sub Form_Load()
sty = GetWindowLong(Me.hwnd, GWL_EXSTYLE)
sty = sty Or WS_EX_LAYERED
SetWindowLong Me.hwnd, GWL_EXSTYLE, sty
SetLayeredWindowAttributes Me.hwnd, 0, 192, LWA_ALPHA
cs = 255
End Sub

Private Sub Timer1_Timer()
cs = cs - 5
SetLayeredWindowAttributes Me.hwnd, 0, cs, LWA_ALPHA
If cs <= 15 Then
cs = 255
End If
End Sub

请观看Timer控件中cs改变使窗体透明效果会发生变化.

[zdingyun]

说明：表单一个Form1，图片框一个PicShape，在图片框内放置任何图片时，系统将使用图片框中的图片为窗体，并且屏蔽图片中白色部分，从而建立特效的变形窗体。这代码来自VB编程技巧10000例(源江科技),供参考:
Option Explicit
Dim MoveTrue As Boolean, OldX As Long, OldY As Long
Private Type BITMAP
bmType As Long
bmWidth As Long
bmHeight As Long
bmWidthBytes As Long
bmPlanes As Integer
bmBitsPixel As Integer
bmBits As Long
End Type
Private Declare Function GetBitmapBits Lib "gdi32" (ByVal hBitmap As Long, ByVal dwCount As Long, lpBits As Any) As Long
Private Declare Function GetObject Lib "gdi32" Alias "GetObjectA" (ByVal hObject As Long, ByVal nCount As Long, lpObject As Any) As Long
Private Declare Function CreateRectRgn Lib "gdi32" (ByVal x1 As Long, ByVal y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Private Declare Function CombineRgn Lib "gdi32" (ByVal hDestRgn As Long, ByVal hSrcRgn1 As Long, ByVal hSrcRgn2 As Long, ByVal nCombineMode As Long) As Long
Private Declare Function SetWindowRgn Lib "user32" (ByVal hwnd As Long, ByVal hRgn As Long, ByVal bRedraw As Long) As Long
Private Declare Function DeleteObject Lib "gdi32" (ByVal hObject As Long) As Long

Private Sub FitToPicture()
Const RGN_OR = 2
Dim border_width As Single
Dim title_height As Single
Dim bm As BITMAP
Dim bytes() As Byte
Dim ints() As Integer
Dim longs() As Long
Dim R As Integer
Dim C As Integer
Dim start_c As Integer
Dim stop_c As Integer
Dim x0 As Long
Dim y0 As Long
Dim combined_rgn As Long
Dim new_rgn As Long
Dim offset As Integer
Dim colourDepth As Integer
ScaleMode = vbPixels
PicShape.ScaleMode = vbPixels
PicShape.AutoRedraw = True
PicShape.Picture = PicShape.Image
' 获取窗体的边框大小
border_width = (ScaleX(Width, vbTwips, vbPixels) - ScaleWidth) / 2
title_height = ScaleX(Height, vbTwips, vbPixels) - border_width - ScaleHeight
' 获取图片大小
x0 = PicShape.Left + border_width
y0 = PicShape.Top + title_height
'给出图片信息
GetObject PicShape.Image, Len(bm), bm
Select Case bm.bmBitsPixel
Case 15, 16:
'MsgBox _
"图片框中图片的颜色大高。",vbExclamation + vbOKOnly
colourDepth = 2
' 分配空格给图片.
ReDim ints(0 To bm.bmWidthBytes \ 2 - 1, 0 To bm.bmHeight - 1)
' 给出图片表面数据
GetBitmapBits PicShape.Image, bm.bmHeight * bm.bmWidthBytes, ints(0, 0)
' 建立表单区域
For R = 0 To bm.bmHeight - 2
C = 0
Do While C < bm.bmWidth
start_c = 0
stop_c = 0
' 查找白色区域,屏蔽
Do While C < bm.bmWidth
If (ints(C, R) And &H7FFF) <> &H7FFF Then Exit Do
C = C + 1
Loop
start_c = C
Do While C < bm.bmWidth
If (ints(C, R) And &H7FFF) = &H7FFF Then Exit Do
C = C + 1
Loop
stop_c = C
If start_c < bm.bmWidth Then
If stop_c >= bm.bmWidth Then stop_c = bm.bmWidth - 1
new_rgn = CreateRectRgn(start_c + x0, R + y0, stop_c + x0, R + y0 + 1)
If combined_rgn = 0 Then
combined_rgn = new_rgn
Else
CombineRgn combined_rgn, combined_rgn, new_rgn, RGN_OR
DeleteObject new_rgn
End If
End If
Loop
Next R
Case 24:
colourDepth = 3
ReDim bytes(0 To bm.bmWidthBytes - 1, 0 To bm.bmHeight - 1)
GetBitmapBits PicShape.Image, bm.bmHeight * bm.bmWidthBytes, bytes(0, 0)
For R = 0 To bm.bmHeight - 2
' Create a region for this row.
C = 0
Do While C < bm.bmWidth
start_c = 0
stop_c = 0
offset = C * colourDepth
Do While C < bm.bmWidth
If bytes(offset, R) <> 255 Or _
bytes(offset + 1, R) <> 255 Or _
bytes(offset + 2, R) <> 255 Then Exit Do
C = C + 1
offset = offset + colourDepth
Loop
start_c = C
Do While C < bm.bmWidth
If bytes(offset, R) = 255 And _
bytes(offset + 1, R) = 255 And _
bytes(offset + 2, R) = 255 _
Then Exit Do
C = C + 1
offset = offset + colourDepth
Loop
stop_c = C
If start_c < bm.bmWidth Then
If stop_c >= bm.bmWidth Then stop_c = bm.bmWidth - 1
' 建立区域
new_rgn = CreateRectRgn(start_c + x0, R + y0, stop_c + x0, R + y0 + 1)
If combined_rgn = 0 Then
combined_rgn = new_rgn
Else
CombineRgn combined_rgn, combined_rgn, new_rgn, RGN_OR
DeleteObject new_rgn
End If
End If
Loop
Next R
Case 32:
colourDepth = 4
ReDim longs(0 To bm.bmWidthBytes \ 4 - 1, 0 To bm.bmHeight - 1)
GetBitmapBits PicShape.Image, bm.bmHeight * bm.bmWidthBytes, longs(0, 0)
For R = 0 To bm.bmHeight - 2
C = 0
Do While C < bm.bmWidth
start_c = 0
stop_c = 0
Do While C < bm.bmWidth
If (longs(C, R) And &HFFFFFF) <> &HFFFFFF Then Exit Do
C = C + 1
Loop
start_c = C
Do While C < bm.bmWidth
If (longs(C, R) And &HFFFFFF) = &HFFFFFF Then Exit Do
C = C + 1
Loop
stop_c = C
If start_c < bm.bmWidth Then
If stop_c >= bm.bmWidth Then stop_c = bm.bmWidth - 1
new_rgn = CreateRectRgn(start_c + x0, R + y0, stop_c + x0, R + y0 + 1)
If combined_rgn = 0 Then
combined_rgn = new_rgn
Else
CombineRgn combined_rgn, combined_rgn, new_rgn, RGN_OR
DeleteObject new_rgn
End If
End If
Loop
Next R
Case Else
MsgBox "对不起，程序必须在 16位, 24-位 或 32-位 颜色下。", _
vbExclamation + vbOKOnly
Exit Sub
End Select
' 设置表单外观为建立区域
SetWindowRgn hwnd, combined_rgn, True
DeleteObject combined_rgn
End Sub

Private Sub Form_Load()
Move (Screen.Width - Width) / 2, (Screen.Height - Height) / 2
FitToPicture
End Sub

Private Sub picShape_DblClick()
Unload Me
End Sub

Private Sub picshape_MouseDown(Button As Integer, Shift As Integer, x As Single, y As Single)
MoveTrue = True
OldX = x: OldY = y
End Sub

Private Sub picshape_MouseMove(Button As Integer, Shift As Integer, x As Single, y As Single)
If MoveTrue = True Then
Form1.Left = Form1.Left + x - OldX
Form1.Top = Form1.Top + y - OldY
End If
End Sub

Private Sub picshape_MouseUp(Button As Integer, Shift As Integer, x As Single, y As Single)
MoveTrue = False
End Sub

'下面的方法仅适用于Windows 2000/XP，因为SetLayeredWindowAttributes函数在其他系统中不支持。）
Public Sub NTSetfrmRgn(PicBox As PictureBox, frm As Form)
'-------------------------------------------------
' 窗体形状及透明度
' Color (取得0,0处象素的颜色,即要裁减的区域的颜色
' SetLayeredWindowAttributes 设置透明度及窗体形状
'-------------------------------------------------
Dim WindowExs As Long, Color As Long
frm.Picture = PicBox.Picture
Color = GetPixel(PicBox.hDC, 0, 0)
WindowExs = GetWindowLong(frm.hwnd, GWL_EXSTYLE)
WindowExs = WindowExs Or WS_EX_LAYERED
SetWindowLong frm.hwnd, GWL_EXSTYLE, WindowExs
SetLayeredWindowAttributes frm.hwnd, Color, 180, LWA_COLORKEY Or LWA_ALPHA
End Sub

[zhejiong]

可是这样flash控件还是有一个长方的背景不是透明的

[熊孩子开学喽]

使用API： SetLayeredWindowAttributes
定义：
Declare Function SetLayeredWindowAttributes Lib "user32.dll" (ByVal hwnd As Long, ByVal crKey As Long, ByVal bAlpha As Byte, ByVal dwFlags As Long) As Long

WS_EX_LAYERED = 0x80000;
LWA_ALPHA = 0x2;
LWA_COLORKEY=0x1
其中dwFlags有LWA_ALPHA和LWA_COLORKEY
LWA_ALPHA被设置的话,通过bAlpha决定透明度.
LWA_COLORKEY被设置的话,则指定被透明掉的颜色为crKey,其他颜色则正常显示

因此只要设置LWA_COLORKEY和crKey，并且将窗体背景色和控件颜色设为 不同的颜色，就可以做到楼主的要求，经实际测试可行

[fankun]

我上次用flashwindow函数的时候，把form1的autodraw属性设置为true，结果除了了窗口标题栏和控件可以看见以外，窗体背景就成了首次show的时候被遮盖的背景了