Resumen Cambiar la resolución por código   (2 mensajes )

On Mon, 24 Nov 1997, tronco wrote:

> Hola amigos.
>
> ¿Alguien me puede decir como cambiar la resolución del entorno Windows por
> código.?
>
> Imagino que será llamando a una función del API de Windows.
>
> ¿ Donde puedo además conseguir información de las funciones que componen
> cada DLL de Windows ?
>
> Gracias.
>

    Te adjunto un fichero con un articulo del kb de Microsoft sobre el
tema.

    Saludos.

**********************************************************
Jordi Garcia Busquets
jordi@hades.udg.es
Estudiante de 3o de informatica de gestion
Universidad de Girona. Catalunya. Espanna
**********************************************************

Tip 204: Changing the Screen Resolution at Run Time in Visual Basic 4.0

February 28, 1996



Abstract

Because Microsoft Windows 95 users may have different screen resolution settings, you may need to set the screen resolution to a specific setting while your Microsoft® Visual Basic® version 4.0 application is running. This article explains how to change your screen resolution from within Visual Basic.



Setting the Screen Resolution

Under the Microsoft® Windows® 95 operating system, you can set your screen resolution by running the Display applet in Control Panel. In a Microsoft Visual Basic® version 4.0 application, you can use the Windows application programming interface (API) EnumDisplaySettings and ChangeDisplaySettings functions to change the screen resolution while your program is running.



The EnumDisplaySettings function allows you to retrieve information about your display's graphics modes. This information is then stored in a DEVMODE structure.



After you have interrogated the computer system with the EnumDisplaySettings function, you use the ChangeDisplaySettings function to tell the operating system to use a different screen resolution.



The ChangeDisplaySettings function lets you set the screen resolution to a different graphics mode. The DEVMODE structure holds the graphics mode information to which you want to change.



In the example program below, you first retrieve the current screen resolution information by calling the EnumDisplaySettings function. The DEVMODE structure contains the graphics modes information for the display type. Next, you modify the dmPelsWidth and dmPelsHeight fields in the DEVMODE structure to reflect the new screen resolution you want to set. Finally, you call the ChangeDisplaySettings function to tell the operating system to set the new screen resolution as the default resolution.



Example Program

This program shows how to set the screen resolution from within a Visual Basic application.



Create a new project in Visual Basic. Form1 is created by default.

Add the following code to the General Declarations section of Form1 (note that each Declare statement must be typed as a single line of code):

Option Explicit

Private Declare Function EnumDisplaySettings Lib "user32" Alias

   "EnumDisplaySettingsA" (ByVal lpszDeviceName As Long,

   ByVal iModeNum As Long, lpDevMode As Any) As Boolean



Private Declare Function ChangeDisplaySettings Lib "user32" Alias

   "ChangeDisplaySettingsA" (lpDevMode As Any, ByVal dwflags As Long) As Long



Const CCDEVICENAME = 32

Const CCFORMNAME = 32

Const DM_PELSWIDTH = &H80000

Const DM_PELSHEIGHT = &H100000



Private Type DEVMODE

    dmDeviceName As String * CCDEVICENAME

    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 * CCFORMNAME

    dmUnusedPadding As Integer

    dmBitsPerPel As Integer

    dmPelsWidth As Long

    dmPelsHeight As Long

    dmDisplayFlags As Long

    dmDisplayFrequency As Long

End Type

Dim DevM As DEVMODEAdd a Command Button control to Form1. Command1 is created by default.

Add the following code to the Click event for Command1:

Private Sub Command1_Click()

    Dim a As Boolean

    Dim i&

    i = 0

    Do

        a = EnumDisplaySettings(0&, i&, DevM)

        i = i + 1

    Loop Until (a = False)

End SubAdd a second Command Button control to Form1. Command2 is created by default.

Add the following code to the Click event for Command2:

Private Sub Command2_Click()

    Dim b&

    DevM.dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT



    DevM.dmPelsWidth = 800

    DevM.dmPelsHeight = 600



    b = ChangeDisplaySettings(DevM, 0)

End SubRun the example program by pressing Click the first Command Button control. This retrieves all the graphics modes for your display. Next, click the second Command Button control to change the display's screen resolution to 800 x 600 graphics mode.



Additional References

"ChangeDisplaySettings QuickInfo Overview Group." (MSDN Library, SDK Documentation, Platform SDK)



"EnumDisplaySettings QuickInfo Overview Group." (MSDN Library, SDK Documentation, Platform SDK)

Mensaje enviado por "Lic. Liliana B. Olivera Rivas" <lorhab@concordia.com.ar>

Hola!!
Fijate si es lo que necesitas...
Suerte!!
Saludos.

----- Original Message -----
From: Francisco José Montilla Rojas <franco@mundomail.net>
To: Lista de Visual Basic <vb-esp@ccc.uba.ar>
Sent: Tuesday, December 15, 1998 4:11 PM
Subject: vb-esp : [ERR] y [API] Funciono


> Gracias, Luis, Carlos, Enrique y Jose por su ayuda, todos acertaron con
> su solucion de tratar todos los reportes con un solo control de crystal,
> funciona perfectamente.
>
> Tengo otra pregunta : ¿ como puedo determinar la resolucion de la
> pantalla ?, para mostrar mi formulario principal creado con una
> resolucion de 640x480 en una resolucion de 800x600, ademas necesito
> saber donde se deben declarar las API y como utilizarlas.
> --
> Francisco J. Montilla R. 1999. [ http://pagina.de/fjm/ ]
> ¡ Si tienes problemas con este e-mail, escribe a: franco01@hotmail.com !
>
> If you have any problem with this e-mail box, just write to :
> franco01@hotmail.com !

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