[Interest] QML window icon

[Alan Alpert]

On Tue, Jan 29, 2013 at 11:05 AM, Rutledge Shawn
<Shawn.Rutledge at digia.com> wrote:
> Mark Summerfield writes:
>> I am trying to create a "pure" QML program, so may main.cpp is simply:
>>
>>     #include <QGuiApplication>
>>     #include <QQmlEngine>
>>     #include <QQuickView>
>>     int main(int argc, char *argv[])
>>     {
>>       QGuiApplication app(argc, argv);
>>       QQmlEngine engine;
>>       QQuickView view(&engine, 0);
>>       view.setSource(QUrl("qrc:/myapp.qml"));
>>       view.show();
>>       return app.exec();
>>     }
>>
>> In myapp.qml I have:
>>
>>     import QtQuick 2.0
>>     import QtQuick.Window 2.0
>>     Window {
>>       title: "Caption"
>>       ...
>>     }
>>
>> But there doesn't seem to be any API for setting the application's icon.
>> (I know I could use QApplication, but I am trying to avoid using
>> QWidget.)
>>
>> Is it possible to set an application icon, and if so, how?
>
> Currently there isn't a way to do it from QML.  This is because we have not exposed QIcon as a QtQuick type.  Window icons can be different sizes, depending on the context in which the windowing system shows them (as a decoration on the title bar, on a task bar or dock, as "tiles" or whatever).  QIcon allows you to provide multiple image sizes, but we didn't design the QML API for that yet.  The simplest is that we could add an image source URL to QQuickWindow, you could provide a medium-sized image for the icon, and it can be scaled down (as small as 16 pixels sometimes); but the result will be less optimal than if you could provide a 16-pixel icon yourself, in addition to the larger one.  We will need icons for Actions too, which we are in the process of adding to QtQuick.  So my opinion is that we need proper icon objects in QtQuick for both use cases.
>
> A QML Window is a QQuickWindow which is a subclass of QWindow, so the method you would want to call is QWindow::setIcon(QIcon &).  Maybe you can create a subclass of QQuickWindow in C++ which sets the icon, do qmlRegisterType to make it available, and instantiate that instead of plain Window? I haven't tried that myself, but it seems like it should work.

There's an even simpler way to do it from C++ - just manage the window
there. QQuickView is a window as well, just use that as the window
(instead of having an empty window as well as the Window{}), and call
setIcon on it. That's just adding  "view.setIcon(icon);" in your
existing C++ code, and using an Item{} as the root of myapp.qml
instead of Window{}.

> Sorry it's not straightforward yet, but I think we will need to add the QML window icon API as soon as we have the Icon API figured out in general.

The Window{} QML API is also really new, so there's a lot more work to
be done with controlling windows from QML. Right now, it's probably
easiest to control the main window from C++.

--
Alan Alpert