Solved

Delphi: How to change secondary display resolution

Posted on 2013-01-14
3
809 Views
Last Modified: 2013-01-14
Hi i want to change the secondary display resolution, im using the following code
but it only changes the main display.

function NewRes(XRes, YRes: DWORD; devnum : cardinal): Integer;
var
DevMode: TDeviceMode;
lpDisplayDevice: TDisplayDevice;
begin

  lpdisplaydevice.cb := sizeof(lpdisplaydevice);
  EnumDisplayDevices(nil,devnum,lpDisplayDevice,0 );   

EnumDisplaySettings(lpdisplaydevice.DeviceName, 0, DevMode);
DevMode.dmFields := DM_PELSWIDTH or DM_PELSHEIGHT or
DM_DISPLAYFREQUENCY;
DevMode.dmPelsWidth := XRes;
DevMode.dmPelsHeight := YRes;
//DevMode.dmDisplayFrequency := Frequency;
Result := ChangeDisplaySettings(DevMode, 0);
end;

Open in new window

0
Comment
Question by:Slinkkkk
  • 2
3 Comments
 
LVL 21

Accepted Solution

by:
developmentguru earned 500 total points
ID: 38774931
Enum Display Settings gets information about one of the graphics modes for a single display device.
http://msdn.microsoft.com/en-us/library/windows/desktop/dd162611(v=vs.85).aspx

I think you may have wanted to call EnumDisplayDevices instead.
http://msdn.microsoft.com/en-us/library/windows/desktop/dd162609(v=vs.85).aspx

That is, only if you need that information.

ChangeDisplaySettings only changes the settings for the default display.
http://msdn.microsoft.com/en-us/library/windows/desktop/dd183411(v=vs.85).aspx

If you need to change settings on other displays, use ChangeDisplaySettingsEx
http://msdn.microsoft.com/en-us/library/windows/desktop/dd183413(v=vs.85).aspx

Let me know if you need more...
0
 

Author Comment

by:Slinkkkk
ID: 38775069
Thx developmentguru,
Here goes the working code if someone else need it

function NewRes(XRes, YRes: DWORD; devnum : cardinal): Integer;
var
DevMode: TDeviceMode;
lpDisplayDevice: TDisplayDevice;
begin

  lpdisplaydevice.cb := sizeof(lpdisplaydevice);
  EnumDisplayDevices(nil,devnum,lpDisplayDevice,0 );   

EnumDisplaySettings(lpdisplaydevice.DeviceName, 0, DevMode);
DevMode.dmFields := DM_PELSWIDTH or DM_PELSHEIGHT or
DM_DISPLAYFREQUENCY;
DevMode.dmPelsWidth := XRes;
DevMode.dmPelsHeight := YRes;
//DevMode.dmDisplayFrequency := Frequency;
Result := ChangeDisplaySettingsEx (lpdisplaydevice.DeviceName,DevMode,0, (CDS_UPDATEREGISTRY), nil);
end;

Open in new window

0
 

Author Closing Comment

by:Slinkkkk
ID: 38775074
function NewRes(XRes, YRes: DWORD; devnum : cardinal): Integer;
var
DevMode: TDeviceMode;
lpDisplayDevice: TDisplayDevice;
begin

  lpdisplaydevice.cb := sizeof(lpdisplaydevice);
  EnumDisplayDevices(nil,devnum,lpDisplayDevice,0 );  

EnumDisplaySettings(lpdisplaydevice.DeviceName, 0, DevMode);
DevMode.dmFields := DM_PELSWIDTH or DM_PELSHEIGHT or
DM_DISPLAYFREQUENCY;
DevMode.dmPelsWidth := XRes;
DevMode.dmPelsHeight := YRes;
//DevMode.dmDisplayFrequency := Frequency;
Result := ChangeDisplaySettingsEx (lpdisplaydevice.DeviceName,DevMode,0, (CDS_UPDATEREGISTRY), nil);
end;
0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
FMX enumerated colours 2 119
Slow Restore if incremental backups using RDiff.exe 4 31
DBCtrlGrid, Delphi, Scroll 7 26
migrate this code to wprk on android 1 4
Introduction The parallel port is a very commonly known port, it was widely used to connect a printer to the PC, if you look at the back of your computer, for those who don't have newer computers, there will be a port with 25 pins and a small print…
Introduction Raise your hands if you were as upset with FireMonkey as I was when I discovered that there was no TListview.  I use TListView in almost all of my applications I've written, and I was not going to compromise by resorting to TStringGrid…
Established in 1997, Technology Architects has become one of the most reputable technology solutions companies in the country. TA have been providing businesses with cost effective state-of-the-art solutions and unparalleled service that is designed…

821 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question