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>; 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#SCROLLBARS_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#SCROLLBARS_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#SCROLLBARS_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
