Change Desktop Wallpaper

[amahta]

@QT-static-prgm It won't. You have to carefully read configure options. I suggest taking a look at this old post of mine about configure options. If I am not mistaken, you need to use "skip" instead of "nomake"

[QT-static-prgm]

And again, thank you so much. What is qtdeclarative good for??

[amahta]

@QT-static-prgm it is related to QML. I usually can live without it :)

[QT-static-prgm]

Next error:

Error: dependent 'C:\Qt\5.5.1\qt-everywhere-opensource-src-5.5.1\qtdeclarative\lib\Qt5Qmld.lib' does not exist.
jom: C:\Qt\5.5.1\qt-everywhere-opensource-src-5.5.1\qtwebchannel\src\webchannel\Makefile [debug-all] Error 2
jom: C:\Qt\5.5.1\qt-everywhere-opensource-src-5.5.1\qtwebchannel\src\Makefile [sub-webchannel-make_first] Error 2
jom: C:\Qt\5.5.1\qt-everywhere-opensource-src-5.5.1\qtwebchannel\Makefile [sub-src-make_first] Error 2
jom: C:\Qt\5.5.1\qt-everywhere-opensource-src-5.5.1\Makefile [module-qtwebchannel-make_first] Error 2

I think it's a kind of Windows 10 problem: https://forum.qt.io/topic/58056/compilation-failure-with-vs2015/3

[mrjj]

@QT-static-prgm
HI just a side note:
I used this on Win 7 to change wallpaper.
(with mingw compiler)
Never tested on window 10, so might not work.

#include "mainwindow.h"
#include <QApplication>
#include <qDebug>

#include <Windows.h>
int setwallpaper (QString filePath ) {
  bool ret = SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, (PVOID)filePath.utf16(), SPIF_SENDWININICHANGE | SPIF_UPDATEINIFILE);
  return ret;
}

int main(int argc, char* argv[]) {
  QApplication a(argc, argv);
  MainWindow w;
  w.show();
  setwallpaper("c:/test.jpg"); // adjust
  return a.exec();
}

[QT-static-prgm]

Your code looks easy. I'll try it. But for now my program shown above is working with the VS compiler.

Thank you all :D

Ok next i'll try to manipulate the image to show the date and clock in the lower right corner. (my university killed the windows clock. That's why i need this ;))

[mrjj]

@QT-static-prgm
hehe so you switch compiler and
compiled all of Qt so you can change
the wallpaper each minute and that way
get a clock ???
:))
That is the spirit if I ever saw one :))

but are you sure they allow to change the wallpaper?

[QT-static-prgm]

@mrjj
That's the aim :D

btw your code works fine as well. It is only faster then the other one. This:

#include "mainwindow.h"
#include <QApplication>
#include <QDebug>
#include "shobjidl.h"
#include <Windows.h>


int setwallpaper (QString filePath ) {
  bool ret = SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, (PVOID)filePath.utf16(), SPIF_SENDWININICHANGE | SPIF_UPDATEINIFILE);
  return ret;
}


int main(int argc, char *argv[])
{
	HRESULT hr = CoInitialize(NULL);
	IDesktopWallpaper *pDesktopWallpaper = NULL;
	hr = CoCreateInstance(__uuidof(DesktopWallpaper), NULL, CLSCTX_ALL, IID_PPV_ARGS(&pDesktopWallpaper));
	if (FAILED(hr))
	{
		qDebug() << "error";
	}
	else
	{
		pDesktopWallpaper->SetWallpaper(NULL, QString("D:\\Bilder\\BMW\\3er nachher.jpg").toStdWString().c_str());
	}

	qDebug() << setwallpaper("D:\\Bilder\\BMW\\f22-wallpaper-1920x1600-16.jpg");

	return 0;
}

causes in first shown the f22-wallpaper-1920x1600-16.jpg image and then 3er nachher. So maybe your code is better and that way there was no need to compile qt for vs.

But ok now i understand building qt a bit better XD

[mrjj]

Ok. good to know,

Next its to create a timer object
http://www.bogotobogo.com/Qt/Qt5_QTimer.php
and then ( code not syntax checked)

// draw time on image
QPixmap pix("D:\\Bilder\\BMW\\3er nachher.jpg");
QPainter paint(pix);
QTime time = QTime::currentTime();
QString text = time.toString("hh:mm");
paint.drawText(pix.width()-100,pix.height()-20,text);

and off u go :)

[QT-static-prgm]

@mrjj You saved my time. Thanks for the commands. I hope there are not too much questions tomorrow than i find some time to implement it in the cip-pool :D

[mrjj]

@QT-static-prgm
Well its a good cause :)
Repel against the clock-less desktops!!
I think it would be the easiest to move all code to the timer object.
and let it draw on image then set it.
over and over :)

[amahta]

I'm glad the problem's solved. What @mrjj just mentioned is definitely much easier. My way was more like an example of using interfaces in Qt. They are of course more complicated but Windows API is changing so I guess you won't lose anything by seeing an interface example!
Good luck both

[mrjj]

@QT-static-prgm said:
Yes, the use of interfaces is much more future
proof and also interesting to see used,
I also tried in mingw and it seems to think
IDesktopWallpaper was iUnknow no matter what i did.
So I guess Visual Studio is indeed better for win development.

[QT-static-prgm]

I tried the code yesterday. Nothing changed. It seams to be a problem of SystemParametersInfo. The function is too powerfull and was blocked. It returns always 0. :( will try the alternative version next

[mrjj]

@QT-static-prgm
hi have you tried to manually set desktop wallpaper.
If they removed the watch, they have might have
taken right to set wallpaper also ?

[QT-static-prgm]

@mrjj I can manual change the wallpaper. That's no problem. They removed the clock because the Microsoft right handle doesn't work for them, so everyone who can see the clock and change it, too. Some students did that and that way the whole account synchronisation was broken. Since that the clock was removed.

I tried to write the clock on the image at my home computer, but i get some errors for this step, too:
QPixmap: Must construct a QGuiApplication before a QPixmap

[mrjj]

@QT-static-prgm said:

Must construct a QGuiApplication

If you do have
QApplication app( argc, argv );

then you must likely have constructed the Pixmap as global before main.

and hence its created before "app"

[QT-static-prgm]

@mrjj It works now :D (on my home pc)

#pragma warning(disable: 4100)
#include <QGuiApplication>
#include <QString>
#include <QDebug>
#include <QPixmap>
#include <QTime>
#include <QPainter>
#include <Windows.h>
#include "shobjidl.h"

inline int setwallpaper(QString filePath)
{
	return SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, (PVOID)filePath.utf16(), SPIF_SENDWININICHANGE | SPIF_UPDATEINIFILE);
}


void setWallpaperAdvanced(QString filePath)
{
	HRESULT hr = CoInitialize(NULL);
	IDesktopWallpaper *pDesktopWallpaper = NULL;
	hr = CoCreateInstance(__uuidof(DesktopWallpaper), NULL, CLSCTX_ALL, IID_PPV_ARGS(&pDesktopWallpaper));
	if (FAILED(hr))
	{
		qDebug() << "error";
	}
	else
	{
		pDesktopWallpaper->SetWallpaper(NULL, filePath.toStdWString().c_str());
	}
}

void drawTime(QPixmap &image, int posX, int posY, QColor color)
{
	QPainter painter(&image);
	painter.setPen(color);
	QFont font;
	font.setBold(true);
	painter.setFont(font);
	QTime time = QTime::currentTime();
	QDate date = QDate::currentDate();
	QString timeText = time.toString("hh:mm");
	QString dateText = date.toString(Qt::DefaultLocaleShortDate);

	painter.drawText(posX+15,posY,timeText);
	painter.drawText(posX,posY+15,dateText);
}


int main(int argc, char **argv)
{

	QGuiApplication a(argc, argv);
	QString originalFilePath("D:\\workspaces\\Qt_default\\WallpaperApp\\wallpaper.jpg");
	QString manipulatedFilePath("D:\\workspaces\\Qt_default\\WallpaperApp\\wallpaper_temp.jpg");

	QTime time;

	while(true)
	{
		time = QTime::currentTime();

		if(time.second() == 0)
		{
			QPixmap image(originalFilePath);
			drawTime(image, image.width()-75, image.height()-150, Qt::white);
			image.save(manipulatedFilePath);
			setWallpaperAdvanced(manipulatedFilePath);
			qDebug() << "changed";
		}
		Sleep(800);
	}

	return 0;
}

I was just wondering if there is a good way to stop the program. Maybe a tray icon that has an close option. Any ideas??

[mKing142]

@QT-static-prgm I have tried your code but I got error.
error: C2065: 'IDesktopWallpaper' : undeclared identifier
error: C2065: 'DesktopWallpaper' : undeclared identifier
error: C2065: 'pDesktopWallpaper' : undeclared identifier
error: C2660: 'CoCreateInstance' : function does not take 3 arguments

beside these I have a question.
What is the file shobjidl.h that you have included?

[mrjj]

@mKing142 said in Change Desktop Wallpaper:

shobjidl.h

This a native win SDK include
https://msdn.microsoft.com/en-us/library/windows/desktop/dd391719(v=vs.85).aspx
Its needed to know some of the types.

Note that with the mingw compiler it would not compile but with visual studio it did.

Note2:
You might need
LIBS += -lOle32
LIBS += User32.lib
LIBS += Ole32.lib
in the .pro file.