Icons rendering on HighDPI displays

[rgaudin]

Although we are using scalable (SVG) Icons, those are not rendered properly on HighDPI displays.
It's clearly visible on the Library tab icon which is the Kiwix bird

There are a lot of topics about this online. It seems that it used to be complex, especially given DPR is per-display and an application can have a window in a HighDPI one and another window on a regular DPI one ; and there's the variations between the different systems and all.

I read that it should be transparent in Qt6 but I haven't tested that. If someone wants to send me qt6 build I'll gladly test.

On current Qt5, I could fix the Icon with just the following… but I'm pretty sure it make the icons ugly on regular DPI

diff --git i/src/kiwixapp.cpp w/src/kiwixapp.cpp
index ed29b52..f7477b0 100644
--- i/src/kiwixapp.cpp
+++ w/src/kiwixapp.cpp
@@ -492,6 +492,7 @@ void KiwixApp::handleItemsState(TabType tabType)
     auto libraryOrSettingsTab =  (tabType == TabType::LibraryTab || tabType == TabType::SettingsTab);
     auto notBookmarkableTab = libraryOrSettingsTab || getTabWidget()->currentArticleUrl().isEmpty();
     auto app = KiwixApp::instance();
+    app->setAttribute(Qt::AA_UseHighDpiPixmaps);
     app->getAction(KiwixApp::ToggleReadingListAction)->setDisabled(libraryOrSettingsTab);
     app->getAction(KiwixApp::ToggleAddBookmarkAction)->setDisabled(notBookmarkableTab);
     app->getAction(KiwixApp::FindInPageAction)->setDisabled(libraryOrSettingsTab);

[kelson42]

We will migrate to QT6 soon in milestone 2.5.0. Thx for the report, I will schedule the fix.

[BhargavMah]

I'm interested in assisting with this issue. Could you provide guidance on the best approach to ensure proper icon rendering across both HighDPI and standard DPI displays?

[kelson42]

@BhargavMah For the moment we migrate to Qt6 then we will see if the bug still occurs.