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Published 20 hours ago • verified publisher icon QupZilla

Native scrollbars decrease smooth scrolling performance

Open equeim opened this issue 7 years ago • 18 comments

QupZilla 2.1.1, Arch Linux. When native scrollbars are enabled, smooth scrolling is not so smooth, looks like like 30 fps.

equeim avatar Mar 10 '17 19:03 equeim

Can't reproduce this on Solus. What are your hardware specs and are you running any other apps when you notice this? If so, which ones?

Vistaus avatar Mar 12 '17 18:03 Vistaus

Video card is AMD Radeon R9 280X, OpenGL driver is radeonsi from Mesa 17.0.1, xf86-video-ati 7.8.99. The issue is present regardless of if I run any other apps.

I also have this issue on Windows 10.

equeim avatar Mar 12 '17 20:03 equeim

I can reproduce it, you can enable FPS counter in web inspector and it's clear that it is locked to 30fps. The problem is rendering the scrollbars (probably because QtWebEngine is QQuickWidget and that doesn't mix well with QtWidgets performance-wise), but I have currently no idea how to fix it. I guess I'll need to disable the native scrollbars by default (or even completely remove this feature).

nowrep avatar Mar 13 '17 08:03 nowrep

...(or even completely remove this feature).

~I'll be so happy if you do it!~

ghost avatar Mar 13 '17 08:03 ghost

You can disable it if you don't like it.

nowrep avatar Mar 13 '17 08:03 nowrep

Ooops, i didn't read carefully, i thought you are talking about „Smooth scrolling“

ghost avatar Mar 13 '17 08:03 ghost

probably because QtWebEngine is QQuickWidget and that doesn't mix well with QtWidgets performance-wise

AFAIK, QWebEngineView is QWidget.

equeim avatar Mar 13 '17 09:03 equeim

AFAIK, QWebEngineView is QWidget.

Not under the hood, it was QOpenGLWidget before and is now QQuickWidget to share the same code as QtQuick version.

https://code.qt.io/cgit/qt/qtwebengine.git/tree/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.cpp

nowrep avatar Mar 15 '17 09:03 nowrep

I double this.

vtronko avatar Mar 15 '17 12:03 vtronko

It's now disabled by default.

nowrep avatar Mar 15 '17 12:03 nowrep

IMHO, it would be a better idea to disable smooth scrolling by default and keep native scrollbars enabled by default if the 2 features conflict.

kkofler avatar Mar 24 '17 00:03 kkofler

@kkofler +++

iondissonance avatar Mar 25 '17 03:03 iondissonance

No, it wouldn't be better. It doesn't affect only smooth scrolling, but the whole rendering. If the scrollbars are redrawn (because the scroll position changed), it halves the frame rate of the whole webview. So, even though it is most visible during smooth scrolling, it will affect also pages that implements smooth scrolling with javascript, ...

Unless I fix the main issue, it will stay as it is (native scrollbars disabled by default).

nowrep avatar Mar 25 '17 09:03 nowrep

I have bad smooth scrolling, but ok native scrollbars. (but good smooth scrolling in firefox and thunderbird)

iondissonance avatar Apr 05 '17 14:04 iondissonance

Running 2.1.2 on Mac OS X, installed via homebrew. Laggy scrolling persists even after disabling animated scroll setting

elfgoh avatar Apr 16 '17 01:04 elfgoh

Disabling animated scrolling have no effect at all, it only makes it less noticeable. You need to disable native scrollbars.

nowrep avatar Apr 16 '17 08:04 nowrep

So it's not a new behavior, strange I haven't noticed this before. And nothing can be done for native scrolls at this moment… I do like native scrolls.

NickLion avatar Jan 13 '18 10:01 NickLion

Hello, I also have this problem when scrolling with touchpad and mouse pointer is pointed over the scrollbar because for some crazy reason smooth-scrolling is forced when scrolling with touchpad

SGOrava avatar Jan 15 '18 19:01 SGOrava