[Interest] unnecessary files in qrc system in webassembly

[Mike Trahearn]

Aha – you nailed it!

Yes, presently the Qt Quick Dialogs do not style in the same way as the compile time styles do for the rest of Qt Quick Controls.
Unfortunately these are still using File Selectors under the hood to pull out the correct QML at run-time according to the style that is set.
Therefore it is necessary to include all styles’ QML files for the non-native dialog implementations whether you are going to use them or not – simply because there is no current way to let the compiler know this in advance.

Qt are aware of this and I understand that Mitch and Fabian have been working on something of a proper solution which may help in the long run:
https://codereview.qt-project.org/c/qt/qtdeclarative/+/476748<https://urldefense.com/v3/__https:/codereview.qt-project.org/c/qt/qtdeclarative/*/476748__;Kw!!Nbma_1s!sJaDFZor5935rQPXkPofNIRMZdWXlSXnJx1ffjiblRUJvup2d01cv_MfJXd4EIVJlOlOaAC1DMyhXL8O-A$>

https://bugreports.qt.io/browse/QTBUG-120056

But for now, not much can be done about it.

Mike


From: Interest <interest-bounces at qt-project.org> on behalf of Adam <qt_interest at xibo.at>
Date: Wednesday, 7 February 2024 at 4:31 am
To: interest at qt-project.org <interest at qt-project.org>
Subject: Re: [Interest] unnecessary files in qrc system in webassembly

Hi,

so I tracked it down to the import of QtQuick.Dialogs. When I import it, the size of the wasm file increases from iirc 34mb to 40, and my debug output shows the fusion and imagine style (plus some others). It makes sense as there are a bunch of native dialogs in there. though i don't know whether they are usable via wasm. In case somebody is finds this, do a full rebuild after removing dialogs. Seems like caching is at work there.

I don't know whether this is a bug or not. These styles don't show in native compilation on linux. and it's certainly surprising, that adding a colour dialogue adds 6mb on your wasm file.

should i report it as a bug?

thanks for the answer, it helped understanding the issue :)
cheers, Adam
On 04/02/2024 17:35, Adam wrote:

Hi,

I'm using Qt 6.6.1 and cmake.

I have imports like this:

import QtQuick
import QtQuick.Controls.Material
import QtQuick.Layouts
import QtQuick.Dialogs

at one point i'm also importing QtQuick.Controls.Universal.

i also verified that at no point i'm importing QtQuick.Controls alone. i'm linking in CMakeLists.txt via:
target_link_libraries(alpineapp PUBLIC nucleus gl_engine Qt::Quick Qt::QuickControls2 Qt::Charts) // Charts removed on my other workstation with no change.

this is the CMakeLists.txt i'm using (along with the rest of the project: https://github.com/adam-ce/alpine_renderer/blob/main/app/CMakeLists.txt<https://urldefense.com/v3/__https:/github.com/adam-ce/alpine_renderer/blob/main/app/CMakeLists.txt__;!!Nbma_1s!rrg6SQO0VebmrkHkCIbpQgK3ju5OecGxvICtkCkGOnnpK3EhS0bKV8AzkCdgAryMH7mqv3zZhfh78Gil1rNp9g$> with automatic builds at https://adam-ce.github.io/alpine_renderer/wasm_singlethread/alpineapp.html<https://urldefense.com/v3/__https:/adam-ce.github.io/alpine_renderer/wasm_singlethread/alpineapp.html__;!!Nbma_1s!rrg6SQO0VebmrkHkCIbpQgK3ju5OecGxvICtkCkGOnnpK3EhS0bKV8AzkCdgAryMH7mqv3zZhfh78GjBgsCSoQ$>

interestingly, on a desktop build, only commonstyle and macstyle are imported (no material style, but it's there in the app).

I also just tried the calqlatr example, replacing the only import of QtQuick.Controls i found with QtQuick.Controls.Material and adding my debug code for printing styles. The result is import of the imagine, basic and fusion style, but surprisingly not material.

I'll try to setup a minimal example on tomorrow.

Thanks, Adam
On 02/02/2024 18:29, Mike Trahearn wrote:
Hi Adam,

How are you using the styles in QML?
Are you importing QtQuick.Controls (only) or are you using specific style imports?
Which version of Qt? CMake assumed?

Assuming the latter and at least Qt 6.2, CMake will only build in the libraries it absolutely needs. But for this to be the case, it needs to know what it needs. Using just import QtQuick.Controls relies on run-time style selection (for which there are different ways to select, all nicely documented). In this case the compiler cannot know in advance which to include, so it has to bring in all of them just in case you run post-build with a different style however it selects it.

For compile-time style selection, you import QtQuick.Controls.Basic/Fusion/Universal .... being specific. Or.. you can use your own style and not Qt Quick Controls at all (albeit it is sometimes hard to not use some of its nice helper types). In this case the compiler only compiles what it needs and there would be nothing in CMake that generates a qrc file with all the run-time style options.

Very obviously this is not your observation so more details on your Qt Quick Controls usage and how you choose your styles and any relevant CMake project/module info would be helpful for someone here to better understand your specific case and more importantly, if there might be a bug.

Mike

________________________________
From: Interest <interest-bounces at qt-project.org><mailto:interest-bounces at qt-project.org> on behalf of Adam <qt_interest at xibo.at><mailto:qt_interest at xibo.at>
Sent: Saturday, February 3, 2024 1:19:35 AM
To: interest at qt-project.org<mailto:interest at qt-project.org> <interest at qt-project.org><mailto:interest at qt-project.org>
Subject: [Interest] unnecessary files in qrc system in webassembly

Hi,

I'm building a QML app for WebAssembly using CMake. When debugging
something else, I printed all files that are in the qrc system. Doing
that, I saw, that the macos, universal and fusion styles are all
compiled in. There are also a bunch of icons for file dialogues etc. I'm
not using them, and they increase the binary (wasm) size.

Is there any way to remove them?

Thanks, Adam
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