The mouse's wheel will halt in SimpleOSRBrowser

[tad.chen]

In the SimpleOSRBrowser Demo, the mouse's wheel sometime will halt after wheel up or down for sometime to scroll the web page. But I still can scroll the web page by the scrollbar at that time.

[salvadordf]

Hi,

The SimpleOSRBrowser demo intercepts the WM_MOUSEWHEEL message in the TAppEvents.OnMessage event.

This is a simple way to get mouse wheel events but it doesn't work if the user move the mouse outside the form.

If that's what you are experiencing then you can use a low level mouse hook with SetWindowsHookEx and WH_MOUSE_LL to intercept all WM_MOUSEWHEEL messages.

[tad.chen]

Hi,

It can work even if the user move the mouse outside the form.

But sometime it'll halt, and the web page has no response no matter how the user scroll the mouse wheel.

Until you close the web page and open again, the mouse wheel will work again.

[salvadordf]

I've seen something like that with some complex or slow websites that cause the renderer to freeze until some resource is loaded.

Can you reproduce that problem with Chrome after you empty the cache?

[tad.chen]

Yes, it comes out very often when visit complex websites.

And the problem still exists after I delete all the files and sub directories in the cache directory.

[tad.chen]

I've solved the problem by cutting down the mouse wheel events. Thank you for your advice.

[salvadordf]

I just found some information related to this issue. It seems that this problem can be fixed disabling some CEF features.

Try adding this before the GlobalCEFApp.StartMainProcess call in the DPR file :

Code: Select all

GlobalCEFApp.SmoothScrolling := STATE_DISABLED;
GlobalCEFApp.DisableFeatures := 'TouchpadAndWheelScrollLatching,AsyncWheelEvents';

For reference :
https://bitbucket.org/chromiumembedded/ ... sing-mouse
https://bitbucket.org/chromiumembedded/ ... ional-with

[tad.chen]

Sorry, I just see your response now. Thank you for your suggestions!

I test it in OSR Demo program according to your advice. It works!

I just use "GlobalCEFApp.SmoothScrolling := STATE_DISABLED".

Maybe my cef4delphi version is a little old, GlobalCEFApp doesn't support DisableFeatures attribute.

But is still work without "GlobalCEFApp.DisableFeatures := 'TouchpadAndWheelScrollLatching,AsyncWheelEvents"