Hi Semyon, Thanks for your help. I did some debugging from that
perspective and could find the problem and the solution. Here is the
new webrev, please review it:
http://cr.openjdk.java.net/~sveerabhadra/8195738/webrev.01/
The problem was that in the case of SCROLLBARS_NEVER, scroll bar info
was set using setScrollInfo() with SIF_RANGE with ranges being (0, 0).
This forced the windows to pick a default value and hence reset it to
that value every time. Now the logic is modified in a very similar
fashion as the other scroll bar display modes but without displaying
it using the new win api ShowScrollBar(). The scroll bar info is
supplied with a proper range per the corresponding base component but
without the scroll bar pane size(as we don’t display it). This should
suffice a good range for the scroll bars to operate and correct itself
if there is any out of range value is supplied.
Thanks and regards,
Shashi
*From:*Semyon Sadetsky
*Sent:* Tuesday, February 27, 2018 1:22 AM
*To:* shashidhara veerabhadraiah
<shashidhara.veerabhadra...@oracle.com>
*Cc:* awt-dev@openjdk.java.net
*Subject:* Re: <AWT Dev> [11] JDK-8195738: scroll poistion in
ScrollPane is reset after calling validate()
The bug was failed against Windows platform. So, I'd try to find the
root cause why when the scroll is notified with the scrolled component
size the scroll position is set to the wrong value.
--Semyon
On 02/26/2018 09:51 AM, shashidhara veerabhadraiah wrote:
I think I agree Semyon. Thanks for your detailed explanation.
So how do we approach on this? I see a different behaviour on other
platforms. Shouldn’t we have a common behaviour across platforms? I
agree with your analysis and hence should we change the behaviour on
other platforms so that all of them will have the same behaviour?
Thanks and regards,
Shashi
On 26-Feb-2018, at 10:17 PM, Semyon Sadetsky
<semyon.sadet...@oracle.com <mailto:semyon.sadet...@oracle.com>>
wrote:
On 02/24/2018 05:27 AM, Shashidhara Veerabhadraiah wrote:
Hi Semyon, Thanks for your review and these questions help
us to reach the right requirements.
Without this change, there is different behavior on windows
compared to Mac/Linux platforms. Hence this change is
required to make the behavior same across the platforms.
Since the scroll pane control is not displayed for the
SCROLLBARS_NEVER case and if not in the setScrollPosition()
then how can the user can move to a different position?
Since we used to update/recalculate the scroll pane geometry
caused changes to move to a different position other than
the setScrollPosition()!! This causes SCROLLBARS_NEVER mode
as unusable as the user is unable to control the scrolling
movement because neither he can set one setScrollPosition()
nor the control is displayed to explicitly set the movement.
Hope this answers your question.
You need to think once again about two facts I brought in my
previous message.
1. User still may scroll using mouse wheel even when scrollbars
are not visible.
2. Visibility of scrollbars doesn't affect the requirement to
notify the scroll about the scrolled component size changes. If
the scrolled component was 500x500 in size and its position in
the 200x200 viewport was (300,300) after the size of the
component is changed to 300x300 it may not be shown at the same
position because the previously visible component area doesn't
exist anymore and the scroll should be moved to (100,100). This
should work in the same way regardless the selected scrlollbar
visibility policy.
--Semyon
Thanks and regards,
Shashi
*From:*Semyon Sadetsky
*Sent:*Saturday, February 24, 2018 2:12 AM
*To:*Shashidhara
Veerabhadraiah<shashidhara.veerabhadra...@oracle.com>
<mailto:shashidhara.veerabhadra...@oracle.com>;awt-dev@openjdk.java.net
<mailto:awt-dev@openjdk.java.net>
*Subject:*Re: <AWT Dev> [11] JDK-8195738: scroll poistion in
ScrollPane is reset after calling validate()
On 2/23/18 10:57 AM, Shashidhara Veerabhadraiah wrote:
Hi Semyon, Whenever the container is resized we used to
update the scroll pane sizes/geometry regardless of the
scroll bar display policies. This resizing make sense
for the non SCROLLBARS_NEVER cases as the scroll pane is
displayed or needed an update. This additional update
posed issues for the SCROLLBARS_NEVER case where we are
not supposed to display the scroll pane per the java
doc, then why update?
Scroll pane geometry gets updated in 2 ways, one thro’
setScrollPosition() and childResized(). So I derived the
conclusion based on the javadoc information that since
we don’t display the scroll pane there is no need to
update the scroll pane geometry based on the
childResized() as it was altering the position already
set by the setScrollPosition(). This behavior is same as
the other non SCROLLBARS_NEVER mode and setting the
scroll bar display to SCROLLBARS_NEVER didn’t made any
difference.
The only difference of SCROLLBARS_NEVER from others I got
from javadoc is that the scroll bar controls are hidden. So
the scrolling itself happens in the same way as in the case
of visible scroll bars but it can be only controlled by
mouse wheel or programmatically. In my understanding this
means that the notification about the scrolled component
size changes should happen in the same way as for all other
cases. I see no reason for the differentiation that your fix
introduces. What will happen if to remove this notification
for visible scroll bars modes?
--Semyon
Thanks and regards,
Shashi
*From:*Semyon Sadetsky
*Sent:*Friday, February 23, 2018 10:17 PM
*To:*Shashidhara
Veerabhadraiah<shashidhara.veerabhadra...@oracle.com>
<mailto:shashidhara.veerabhadra...@oracle.com>;awt-dev@openjdk.java.net
<mailto:awt-dev@openjdk.java.net>
*Subject:*Re: <AWT Dev> [11] JDK-8195738: scroll
poistion in ScrollPane is reset after calling
validate()
On 2/22/18 8:23 PM, Shashidhara Veerabhadraiah wrote:
Hi Semyon, Thanks for your review comments.
Here are those different scroll bar pane modes and
their description:
*Modifier and Type*
*Field*
*Description*
|static int|
*SCROLLBARS_ALWAYS
<https://docs.oracle.com/javase/9/docs/api/java/awt/ScrollPane.html#SC
ROLLBARS_ALWAYS>*
Specifies that horizontal/vertical scrollbars should
always be shown regardless of the respective sizes
of the scrollpane and child.
|static int|
*SCROLLBARS_AS_NEEDED
<https://docs.oracle.com/javase/9/docs/api/java/awt/ScrollPane.html#SC
ROLLBARS_AS_NEEDED>*
Specifies that horizontal/vertical scrollbar should
be shown only when the size of the child exceeds the
size of the scrollpane in the horizontal/vertical
dimension.
|static int|
*SCROLLBARS_NEVER
<https://docs.oracle.com/javase/9/docs/api/java/awt/ScrollPane.html#SC
ROLLBARS_NEVER>*
Specifies that horizontal/vertical scrollbars should
never be shown regardless of the respective sizes of
the scrollpane and child.
This javadoc, you've copy-pasted here, doesn't explain
why in your fix the notification about changed child
size is disabled for SCROLLBARS_NEVER case.
Thanks and regards,
Shashi
*From:*Semyon Sadetsky
*Sent:*Thursday, February 22, 2018 11:58 PM
*To:*Shashidhara
Veerabhadraiah<shashidhara.veerabhadra...@oracle.com>
<mailto:shashidhara.veerabhadra...@oracle.com>;awt-dev@openjdk.java.net
<mailto:awt-dev@openjdk.java.net>
*Subject:*Re: <AWT Dev> [11] JDK-8195738: scroll
poistion in ScrollPane is reset after calling
validate()
Hi Shashi,
Can you clarify what is the principal difference
between SCROLLBARS_NEVER and other scroll policies
that requires to avoid updating the scroll geometry
according to the inner component size?
--Semyon
On 02/19/2018 11:08 PM, Shashidhara Veerabhadraiah
wrote:
Hi All, Please review a code fix for the below bug.
Bug:https://bugs.openjdk.java.net/browse/JDK-8195738
Webrev:http://cr.openjdk.java.net/~sveerabhadra/8195738/webrev.00/
<http://cr.openjdk.java.net/%7Esveerabhadra/8195738/webrev.00/>
Problematic platform: Windows only.
Summary: This bug occurs only on windows
platform and whereas the behavior is different
on Mac/Linux platforms. Now after this fix there
is common behavior across the platforms.
The main problem was with resetting the state of
the scroll bars even though the scroll bar panes
are spawned with SCROLLBARS_NEVER as the scroll
bar display policy. This resetting should not
occur as the scroll bar display policy makes
the
scroll bar panes invisible. Hence except the
setScrollPosition() calls, we don’t need to
resize/update the scroll bars state upon calling
the scroll bars validation if SCROLLBARS_NEVER
policy is used as the scroll bars are not displayed.
Thanks and regards,
Shashi
