Feature Request - Add WPF TouchScroll/Multitouch Support

[dinoc]

I guess this is more of a feature request than an issue but it would be nice to have multitouch support:

-Scrolling with one finger
-Zooming with pinch zoom gesture

[amaitland]

https://bitbucket.org/chromiumembedded/cef/issues/1059/cef3-multi-touch-support-with-offscreen

Until the upstream issue has been resolved it's not possible to implement MultiTouch in the WPF version. If you require it now then you will have to use the the WinForms version hosted in a WindowsFormsHost control.

Please no further comments asking when it will be ready, it's out of our control.

[amaitland]

https://bitbucket.org/chromiumembedded/cef/pull-requests/201/multi-touch-support-for-osr/diff

[Clemani]

I have tested on MS Surface Pro 4. I changed the CefSharp.Wpf.Example project to use ChromiumWebBrowserWithTouchSupport.
Touch scroll and zoom works fine so far. Maybe not 100% as smoothly as in WinForms... but good in my quick tests.

I encountered one issue:
Marking text with stylus does not work. When i move the pen down, press the right-click button and move the pen then no text gets selected. Sometimes one word gets selected but i cannot select a text area.

When i do this another issue happens:
o Enter www.google.com into the address box and press enter.
o Try to select a text with with pen and right click button
o Click into the address box with pen
Then a click with pen into the search box has no effect, the input focus remains in the address box.
When i click with my finger long time in the search box then the search box gets focused.

The input focus issue happens also in CefSharp.WinForms.Example. There i can reproduce it by:
o Enter www.google.com into the address box and press enter.
o Click with pen into the search box.
The search box seems to get focused, the cursor is blinking in the search box... but pressing keys has no effect.
This input focus issue happens also in CefGlue and cefclient.exe, so i guess it's a CEF or Chromium error.
My workaround for this is to watch for WM_PARENTNOTIFY: WM_LBUTTONDOWN, WM_MBUTTONDOWN, WM_RBUTTONDOWN, WM_XBUTTONDOWN, WM_POINTERDOWN and focus the CEF browser window when it's not focused.

[amaitland]

Stylus/Pen support has been improved in #2817 the changes will be in version 75, it's still Experimental.

Anyone testing this out please report back here.

[amaitland]

Unless there are any further reports of errors between now and the 77 release then the code from CefSharp.Wpf.Experimental.ChromiumWebBrowserWithTouchSupport will be merged into the default ChromiumWebBrowser class.

Anyone who has a few moments please test CefSharp.Wpf.Experimental.ChromiumWebBrowserWithTouchSupport and report back if you experience any problems.

[Clemani]

Sorry amaitland - installing x86 version of Visual C++ runtime helped - i deleted the issue.
I changed namespace from CefSharp.Wpf.Experimental to CefSharp.Wpf in ChromiumWebBrowserWithTouchSupport.cs
Then i replaced ChromiumWebBrowser by ChromiumWebBrowserWithTouchSupport where i thought it makes sense (in XAML and on new statements) in CefSharp.Wpf.Example project.
On my Tablet i cannot scroll or zoom with my fingers. I think in my previous test i did the same and it worked. How can i make it working?

[amaitland]

can you kindly explain us how to enable ChromiumWebBrowserWithTouchSupport ?

@cristiancarli Use ChromiumWebBrowserWithTouchSupport instead of ChromiumWebBrowser in your Xaml or .Net code.

On my Tablet i cannot scroll or zoom with my fingers. I think in my previous test i did the same and it worked. How can i make it working?

@Clemani If you are using a build of master (which I don't recommend for testing, use https://github.com/cefsharp/CefSharp.MinimalExample instead) then you will need to comment out

System.AppContext.SetSwitch("Switch.System.Windows.Input.Stylus.DisableStylusAndTouchSupport", true);

At line https://github.com/cefsharp/CefSharp/blob/master/CefSharp.Wpf.Example/App.xaml.cs#L16

There's a bug in WPF (dotnet/wpf#1323) that I've temp disabled DisableStylusAndTouchSupport to allow for testing of another feature/improvement.

[Clemani]

Thanks amaitland.
I tested today with master branch and CefSharp.Wpf.Example.
Touch scroll and zoom seems to work fine.
But with ChromiumWebBrowserWithTouchSupport selecting text with pen does not work anymore, and there is an issue with keyboard input. Please see my comment from May 28 which fully applies also to current master branch.
Not an issue, but i miss the "afterburner" effect when i scroll by finger. In the WinForms version when i move the finger and lift it off while i am moving the browser continues to scroll for a while - this does not happen in ChromiumWebBrowserWithTouchSupport.

[DelTaGC]

@amaitland Hi, will the multitouch feature of CefSharp.Wpf.Experimental.ChromiumWebBrowserWithTouchSupport also be available in 77 for CefSharp.OffScreen.ChromiumWebBrowser? For example by injecting fingers events like currently existing SendMouseClickEvent() and SendMouseWheelEvent()...

[amaitland]

But with ChromiumWebBrowserWithTouchSupport selecting text with pen does not work anymore

@Clemani Thanks for the feedback, based on this I'll leave out the Pen/Stylus methods. I don't have a Pen/Stylus so I cannot test this currently so I was wondering if it might be best left as part of the Experimental implementation. Will merge basic touch support into ChromiumWebBrowser

there is an issue with keyboard input.

Can you please clarify which keyboard issue

Not an issue, but i miss the "afterburner" effect when i scroll by finger. In the WinForms version when i move the finger and lift it off while i am moving the browser continues to scroll for a while - this does not happen in ChromiumWebBrowserWithTouchSupport.

How does the CEF Sample application behave? You can download from http://opensource.spotify.com/cefbuilds/cef_binary_77.1.6%2Bga0ea7e6%2Bchromium-77.0.3865.90_windows32_client.tar.bz2

Please test with the following

cefclient --multi-threaded-message-loop --off-screen-rendering-enabled --enable-gpu

For example by injecting fingers events like currently existing SendMouseClickEvent() and SendMouseWheelEvent()...

@DelTaGC The SendTouchEvent method was added in version 73. Look at the ChromiumWebBrowserWithTouchSupport source if you need an example.

[amaitland]

Touch support has been moved from ChromiumWebBrowserWithTouchSupport to ChromiumWebBrowser in commit b31a365

Stylus/Pen support is still in ChromiumWebBrowserWithTouchSupport. I'll likely close this issue and create a new one to track adding Stylus/Pen support.

[Clemani]

Can you please clarify which keyboard issue

o For ex. enter www.google.com into the address box and press enter.
o Try to select a text on the web page with with pen and right click button
o Click into the address box with pen
o Then a click with pen into the search box on the web page has no effect, the input focus remains in the address box.
I cannot reproduce this reliable, sometimes the issue happens and sometimes not. When you have no pen then i think you cannot reproduce this issue.

Off-topic: The WinForms keyboard issue on touch devices is described here: https://bitbucket.org/chromiumembedded/cef/issues/1797/windows-touch-does-not-return-focus-to-the

How does the CEF Sample application behave? ...

How can i inject finger events ? Changing and compiling CEF is out of my scope.

[amaitland]

How can i inject finger events ? Changing and compiling CEF is out of my scope.

@Clemani Just download an run cefclient from the link provided with the command line args referenced. If the fling behaviour works there then we can look at implementing it, if not then it's unlikely something CEF supports.

[Clemani]

With this commandline args i cannot do anything in cefclient on a web page, finger and pen does not work at all.

[amaitland]

It appears that Fling scrolling is currently broken in CEF. Relevant issue is https://bitbucket.org/chromiumembedded/cef/issues/2745/osr-fling-scrolling-doesnt-work-in-without

[amaitland]

It appears that Fling scrolling is currently broken in CEF. Relevant issue is https://bitbucket.org/chromiumembedded/cef/issues/2745/osr-fling-scrolling-doesnt-work-in-without

Fling Scrolling should now be resolved upstream

[amaitland]

Touch Support will be part of version 79, Stylus support is still only in the CefSharp.Wpf.Experimental.ChromiumWebBrowserWithTouchSupport class, I've created
#3028 to track progress of resolving the final issues, if you experience problems with Stylus please comment on #3028 instead of here.

Anyone experiencing problems with Touch Support in version 79 or above please open a new issue using the Bug Report Template, please make sure to include a detailed list of steps to reproduce the problem you are seeing.

[amaitland]

There is no default virtual keyboard implementation as WPF doesn't provide an out of the box solution that works on all supported operating systems. If you require a virtual keyboard when using your touch screen please read OnScreen Virtual Keyboard. There's some additional information in #1736