<AWT Dev> [11] JDK-8195738: scroll poistion in ScrollPane is reset after calling validate()
semyon.sadetsky at oracle.com
semyon.sadetsky at oracle.com
Thu Mar 1 17:46:38 UTC 2018
On 3/1/18 9:37 AM, semyon.sadetsky at oracle.com wrote:
> On 2/28/18 8:09 PM, Shashidhara Veerabhadraiah wrote:
>
>> Hi Semyon, It is not getting decreased for the case of
>> SCROLLBARS_NEVER. The Boolean flags “needsHorz” and “needsVert” are
>> false for the never case and true for the other cases. We decrease by
>> the size of the scroll bars only for the true cases, so in the false
>> case we will use the entire width and height(SM_CXEDGE and SM_CYEDGE).
>>
> Can you clarify this a bit more? I see the next lines executed without
> any conditions
>
> 215 parentWidth -= (horzBorder * 2);
> 216 parentHeight -= (vertBorder * 2);
I was not right this is just borders.
Looks good to me.
--Semyon
>
> --Semyon
>>
>> Thanks and regards,
>> Shashi
>>
>> *From:*Semyon Sadetsky
>> *Sent:* Thursday, March 1, 2018 12:39 AM
>> *To:* Shashidhara Veerabhadraiah <shashidhara.veerabhadraiah at oracle.com>
>> *Cc:* awt-dev at openjdk.java.net
>> *Subject:* Re: <AWT Dev> [11] JDK-8195738: scroll poistion in
>> ScrollPane is reset after calling validate()
>>
>> Hi Sashi,
>>
>> The parent with and height shouldn't be decreased by the size of the
>> scrollbars in case of SCROLLBARS_NEVER.
>>
>> --Semyon
>>
>> On 2/27/2018 12:45 AM, Shashidhara Veerabhadraiah wrote:
>>
>> 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/
>> <http://cr.openjdk.java.net/%7Esveerabhadra/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.veerabhadraiah at oracle.com>
>> <mailto:shashidhara.veerabhadraiah at oracle.com>
>> *Cc:* awt-dev at openjdk.java.net <mailto:awt-dev at 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.sadetsky at oracle.com
>> <mailto:semyon.sadetsky at 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.veerabhadraiah at oracle.com>
>> <mailto:shashidhara.veerabhadraiah at oracle.com>;awt-dev at openjdk.java.net
>> <mailto:awt-dev at 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.veerabhadraiah at oracle.com>
>> <mailto:shashidhara.veerabhadraiah at oracle.com>;awt-dev at openjdk.java.net
>> <mailto:awt-dev at 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.veerabhadraiah at oracle.com>
>> <mailto:shashidhara.veerabhadraiah at oracle.com>;awt-dev at openjdk.java.net
>> <mailto:awt-dev at 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
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/awt-dev/attachments/20180301/23be770d/attachment-0001.html>
More information about the awt-dev
mailing list