Hello Shashi, Alexey and Sergey,

Shashi, I know that "WM_GESTURE" is mutually exclusive with "WM_TOUCH" which is used by my fix for JDK-8166772, according to the next quotation from the MSDN page (https://msdn.microsoft.com/en-us/library/windows/desktop/dd371581(v=vs.85).aspx). "Note By default, you receive WM_GESTURE messages instead of WM_TOUCH messages. If you call RegisterTouchWindow, you will stop receiving WM_GESTURE messages."

Sergey, Alexey and Shashi,

I debugged this issue (JDK-8178361), identified the root cause of this bug and created my own 2 line length alternative version of the fix for this bug. This bug is a bug in JDK and is not caused by lack of support of the touch input by JDK on Windows OS. My fix does not involve any touch input API. Please review my fix and find the explanation of the root cause of the bug.

Webrev: http://cr.openjdk.java.net/~alitvinov/8178361/jdk10/webrev.00

THE ROOT CAUSE OF THE BUG:
The event "java.awt.event.MouseEvent.MOUSE_CLICKED" is not sent from the native method "AwtComponent::WmMouseUp" to the event queue for "WM_LBUTTONUP" message related to the second touch (tap) of the double touch user action. Tracing shows that in reality:

1. During a double click and a double touch "AwtComponent" window always receives 2 pairs of "WM_LBUTTONDOWN/WM_LBUTTONUP" messages, thus JDK already has support of the double touch action via "WM_LBUTTONDOWN/WM_LBUTTONUP" messages. 2.1. For each "WM_LBUTTONDOWN" in "AwtComponent::WmMouseDown" JDK sends 1 "java.awt.event.MouseEvent" (MOUSE_PRESSED). 2.2. For each "WM_LBUTTONUP" in "AwtComponent::WmMouseUp" JDK sends 2 "java.awt.event.MouseEvent" (MOUSE_RELEASED, MOUSE_CLICKED).

However, when the double touch is done "MOUSE_CLICKED" event is not sent for "WM_LBUTTONUP" from the 2nd pair of "WM_LBUTTONDOWN/WM_LBUTTONUP" messages, because "m_mouseButtonClickAllowed" equals "0" and the next condition in "AwtComponent::WmMouseUp" is not satisfied:

if ((m_mouseButtonClickAllowed & GetButtonMK(button)) != 0) { //CLICK allowed
        SendMouseEvent(java_awt_event_MouseEvent_MOUSE_CLICKED,
::JVM_CurrentTimeMillis(NULL, 0), x, y, GetJavaModifiers(),
                       clickCount, JNI_FALSE, GetButton(button));
    }

It occurs, because between the 2nd pair of the messages "WM_LBUTTONDOWN/WM_LBUTTONUP" the messages "WM_MOUSEMOVE" arrive, so "x", "y" coordinates of "WM_LBUTTONDOWN", "WM_LBUTTONUP" are different. JDK handles "WM_MOUSEMOVE", and in "AwtComponent::WmMouseMove" this event is treated as "dragging" and the next expression is executed.

    "m_mouseButtonClickAllowed = 0;"

Therefore in "AwtComponent::WmMouseUp" it is decided not to send "java.awt.event.MouseEvent.MOUSE_CLICKED" for the end of dragging.

THE FIX:
The fix allows to send "java.awt.event.MouseEvent.MOUSE_CLICKED" event from "AwtComponent::WmMouseUp" for the case, when "clickCount" exceeds "1". If JDK already associates 2 "WM_LBUTTONDOWN" messages in "AwtComponent::WmMouseDown" as a double or triple click, then it is possible to consider that no dragging happened between these messages.

Thank you,
Anton

On 28/09/2017 03:11, Shashidhara Veerabhadraiah wrote:

Hi Anton, Thank you for your review comments. Please see below for my replies.

Thanks and regards,

Shashi

*From:*Anton Litvinov
*Sent:* Tuesday, September 26, 2017 6:55 AM
*To:* Shashidhara Veerabhadraiah <shashidhara.veerabhadra...@oracle.com>; Alexey Ivanov <alexey.iva...@oracle.com>; Sergey Bylokhov <sergey.bylok...@oracle.com>
*Cc:* awt-dev@openjdk.java.net
*Subject:* Re: <AWT Dev> [10] JDK-8178361: JFileChooser does not allow to open folders with a double tap when using the touch screen interface

Hi Shashi,

I am also reviewing your fix since last week. I built "jdk10/client" with your fix and was able to see, how the 1st and the 2nd versions of your fix work. I have the following remarks and questions to you:

1. The fix causes a rather significant regression, which is a loss of the drag functionality using the touch screen. To reproduce it you can use "SwingSet2" demo application, where try to move any of the internal frames on the first tab of the demo application using the touch screen. Also you can try to select text in JTextField in that demo application using the touch screen. I think that this regression is serious and should be addressed in this fix.

*/[Shashi] I found the problem that was causing this issue. It is to do with the drag capture/release implemented in the WmMouseDown() and WmMouseUp() functions. This does not handles the touch drag as such and we need to implement a new touch gesture to enable the same functionality./*

2. Why is it necessary for your fix to handle "WM_POINTERENTER", "WM_POINTERLEAVE" messages?

*/[Shashi] Currently we are mapping the touch input to mouse input and the mouse input follows a protocol of sending a mouse enter to and exit from a window event before processing further events. This same is implemented thro’ Pointer enter and pointer leave messages./*

3. According to MSDN the used by you Win32 API function "GetPointerInfo" and "WM_POINTER*" messages are available on Windows 8 or later OS versions, what means that they are not available on older OS versions, for example on Windows 7, and what means that your fix will not resolve the bug for Windows 7.

Windows 7 is supported by JDK 9 (http://www.oracle.com/technetwork/java/javase/jdk9certconfig-3761018.html), and obviously JDK 10 also supports Windows 7, therefore the bug should be fixed also for Windows 7, if it is reproducible on that OS.

*/[Shashi] Thanks for pointing this out. Windows 7 offers a different touch input method via the WM_GESTURE and here is the link for it: https://msdn.microsoft.com/en-us/library/windows/desktop/dd940543(v=vs.85).aspx <https://msdn.microsoft.com/en-us/library/windows/desktop/dd940543%28v=vs.85%29.aspx>. I am exploring a way to implement the same in the coming update./*

*/As one can see, there are a lot of major updates that needs to be done for this feature to be complete. It will take some more days to do this, hence please wait for some time till I produce a new update./*

Thank you,
Anton

On 25/09/2017 07:29, Shashidhara Veerabhadraiah wrote:

    Hi Alexey, Thank you for pointing that out. I misread the info
    that EnableMouseInPointer() is a must call and would enable the
    WM_POINTER messages being sent to the component. But actually it
    is not required to be enabled and as you rightly pointed out that
    it would convert the WM_MOUSE to the WM_POINTER messages.

    Below is the Webrev that does this change. Now since mouse in
    pointer is disabled, the mouse behavior should /_not_/ have any
    effect at all by this software updates.

    Webrev:
    http://cr.openjdk.java.net/~sveerabhadra/8178361/webrev.01/
    <http://cr.openjdk.java.net/%7Esveerabhadra/8178361/webrev.01/>

    For additional replies, please see below.

    Thanks and regards,

    Shashi

    *From:*Alexey Ivanov
    *Sent:* Friday, September 22, 2017 5:19 PM
    *To:* Shashidhara Veerabhadraiah
    <shashidhara.veerabhadra...@oracle.com>
    <mailto:shashidhara.veerabhadra...@oracle.com>; Sergey Bylokhov
    <sergey.bylok...@oracle.com> <mailto:sergey.bylok...@oracle.com>
    *Cc:* awt-dev@openjdk.java.net <mailto:awt-dev@openjdk.java.net>
    *Subject:* Re: <AWT Dev> [10] JDK-8178361: JFileChooser does not
    allow to open folders with a double tap when using the touch
    screen interface

    Hi Shashi,

    You use EnableMouseInPointer which converts classical WM_MOUSE
    events to WM_POINTER events. This could have substantial effect on
    AWT components behaviour. I am worried about High DPI support,
    drag-and-drop functionality etc.

    */[Shashi] This is not required and hence removed./*

    Is there a simpler way to handle double-tap?
    Windows converts taps to clicks, i.e. the app receives
    WM_LBUTTONDOWN and WM_LBUTTONUP.
    Have you tried to find out why double-tap is not converted to
    double-click?

    */[Shashi] Since the mouse in pointer is disabled and a windows
    icon behavior is different from a windows button behavior(Because
    the a touch on the icon does not translate to a left button down
    event whereas it does for a windows button(file name!!)), it is
    required to bring in the WM_POINTER message type into the
    component message handling routine./*

    Do right and middle mouse buttons continue to work as expected?
    Mouse wheel? Any additional mouse buttons?

    */[Shashi] It should not have any effect after mouse in pointer is
    disabled./*

    The documentation for EnableMouseInPointer [1] says: “This
    function can be called only once in the context of a process
    lifetime.” You call it for every component created. It would have
    been enough to call it once during Toolkit initialization.


    Regards,
    Alexey

    [1]
    
https://msdn.microsoft.com/en-us/library/windows/desktop/hh447467(v=vs.85).aspx
    
<https://msdn.microsoft.com/en-us/library/windows/desktop/hh447467%28v=vs.85%29.aspx>

    On 19/09/2017 04:35, Shashidhara Veerabhadraiah wrote:

        Hi Sergey, When I checked it was not working on the Java applications. 
None of the controls could take touch click events but it used to highlight 
because when we touch on the touch screen interface the system moves the cursor 
over to the touch point thereby enabling mouse focus events being sent.

        Thanks and regards,

        Shashi

        -----Original Message-----

        From: Sergey Bylokhov

        Sent: Tuesday, September 19, 2017 3:39 AM

        To:shashidhara.veerabhadra...@oracle.com
        <mailto:shashidhara.veerabhadra...@oracle.com>  >> Shashidhara 
Veerabhadraiah<shashidhara.veerabhadra...@oracle.com>
        <mailto:shashidhara.veerabhadra...@oracle.com>

        Cc:awt-dev@openjdk.java.net <mailto:awt-dev@openjdk.java.net>

        Subject: Re: <AWT Dev> [10] JDK-8178361: JFileChooser does not allow to 
open folders with a double tap when using the touch screen interface

        Hi, Shashi.

        Why the bug is JFileChooser specific?

        Does it means that it works for other elements(buttons/lists/menu/etc)?

        On 9/18/17 08:58, Shashidhara Veerabhadraiah wrote:

            Hi All, Please review this software changes for the /_enhancement_/

            JDK-8178361.

            Issue: Request was filed to enable the touch event processing for 
Java

            client applications.

            Fix: Windows platform offers 'pointer' implementation thro' which 
one

            can tap for the touch inputs as well. A typical 'pointer' function 
may

            contain touch, pen, touch pad or mouse inputs. This allows for a

            uniform input processing though the event source may defer. This fix

            enables the 'touch' events(via TOUCH pointer) to be passed to the

            components using the other type of pointer 'mouse'. Essentially 
there

            is a conversion put in place to convert a touch event input into a

            left click mouse event. I think this is the right thing to do

            considering desktop scenarios to which the typical Java applications

            that gets exposed to. This is also the same behavior on my touch

            enabled windows 10 laptop as well. Please let me know if a 
different behavior is expected. Below is the output:

            Now touch event works as a typical mouse left click as in general. 
But

            there is an issue because the icon size of the Java UI is typically

            small, touching that icon exactly is sometimes difficult. This is

            handled by an Windows application by having larger icon size or icon

            view as a standard. Hence I believe this is outside the scope this

            software update. Any changes to it would be done later as a new bug 
or

            an enhancement.

            Bug ID:https://bugs.openjdk.java.net/browse/JDK-8178361

            Webrev:http://cr.openjdk.java.net/~sveerabhadra/8178361/webrev.00/
            <http://cr.openjdk.java.net/%7Esveerabhadra/8178361/webrev.00/>

            Thanks and regards,

            Shashi

        --

        Best regards, Sergey.


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