动态改变及恢复屏幕设置

Question

Const CCHDEVICENAME = 32
Const CCHFORMNAME = 32

Private Type DEVMODE
dmDeviceName As String * CCHDEVICENAME
dmSpecVersion As Integer
dmDriverVersion As Integer
dmSize As Integer
dmDriverExtra As Integer
dmFields As Long
dmOrientation As Integer
dmPaperSize As Integer
dmPaperLength As Integer
dmPaperWidth As Integer
dmScale As Integer
dmCopies As Integer
dmDefaultSource As Integer
dmPrintQuality As Integer
dmColor As Integer
dmDuplex As Integer
dmYResolution As Integer
dmTTOption As Integer
dmCollate As Integer
dmFormName As String * CCHFORMNAME
dmUnusedPadding As Integer
dmBitsPerPel As Integer
dmPelsWidth As Long
dmPelsHeight As Long
dmDisplayFlags As Long
dmDisplayFrequency As Long
End Type  

　　------------------设置屏幕的核心API-----------------

Private Declare Function ChangeDisplaySettings
Lib "User32" Alias "ChangeDisplaySettingsA"
(ByVal lpDevMode As Long, ByVal dwflags As Long) As Long

　　------------------设置屏幕的函数-----------------

Public Function SetDispMode(Width As Integer,
Height As Integer, Color As Integer) As Long

　　（SetDispMode是自己构造的更改屏幕设置的函数来，它的三个参数Width、Height和Color分别是屏幕的横向分辨率、纵向分辨率,颜色位数，其值可为24，16，0等。0为原有颜色设置。）

Const DM_PELSWIDTH = &H80000
Const DM_PELSHEIGHT = &H100000
Const DM_BITSPERPEL = &H40000
Dim NewDevMode As DEVMODE
Dim pDevmode As Long
With NewDevMode
.dmSize = 122
If Color = 0 Then

　　如果Color=0则只改变屏幕的分辨率，而不改变色彩。



.dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT
Else  

　　如果Color不等0则改变屏幕的分辨率和色彩。

.dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT Or DM_BITSPERPEL
End If
.dmPelsWidth = Width
.dmPelsHeight = Height
If Color < > 0 Then
.dmBitsPerPel = Color
End If
End With
pDevmode = lstrcpy(NewDevMode, NewDevMode)

　　得到一个指向NewDevMode结构的Long型的指针。



ChangeDisplaySettings pDevmode, 0
End Function  

　　三、在工程窗体中，加入两个按钮Command1和Command2，其Caption属性分别为“800x600x16”和“恢复原设置”。

　　其程序代码为：

　　窗口的“通用|声明”区



Option Explicit
Dim H, V, Color As Long  

　　声名变量，用于保存最初屏幕设置
　　Private Sub Form_Load()
　　---------------以下代码用于得到最初的屏幕设备--------------



H = GetDeviceCaps(Form1.hdc, HORZRES)
V = GetDeviceCaps(Form1.hdc, VHORZRES)
Color = GetDeviceCaps(Form1.hdc, BITSPIXEL)
End Sub

Private Sub Command1_Click()  

　　调用SetDispMode函数改变屏幕设置



SetDispMode 800, 600, 16
End Sub

Private Sub Command2_Click()  

　　恢复最初屏幕设置

SetDispMode Cint(H), Cint(V), Cint(Color)
End Sub

　　四、将程序编译执行。

　　本程序执行后，如果单击Command1，则您的计算机屏幕显示模式将被设置为“800x600x16”的显示模式；如果单击Command2, 则您的计算机屏幕显示模式将被设置为原来的显示模式。此程序稍加修改，即可放置于桌面或任务栏中，直接快捷的修改屏幕设置。