Re: Catalina scroll view issues
Re: Catalina scroll view issues
- Subject: Re: Catalina scroll view issues
- From: Redler Eyal via Cocoa-dev <email@hidden>
- Date: Mon, 16 Dec 2019 11:09:03 +0200
Thanks Rob, Makes sense although the issue is not consistent on Catalina (I
think this is something only a minority of my app users on Catalina are
experiencing - and I wasn't able to reproduce it). I saw this deprecation but
could not be sure if it means that it is always on or always off. I guess
always on makes more sense. I tried turning copiesOnScroll to on and sent a
build to my users so we'll see if it is related - I really dislike solving
issues I cannot confirm fixed myself.
Eyal
> On 14 Dec 2019, at 22:08, Rob Petrovec <email@hidden> wrote:
>
> From
> https://developer.apple.com/documentation/appkit/nsclipview/1532142-copiesonscroll?language=objc
> copiesOnScroll
> A Boolean value that indicates if the clip view copies rendered images while
> scrolling.
> Discussion
> When the value of this property is YES, the clip view copies its existing
> rendered image while scrolling (only drawing exposed portions of its document
> view); when it is NO, the view forces its contents to be redrawn each time.
>
> From NSClipView.h:
> @property BOOL copiesOnScroll API_DEPRECATED("NSClipView will always
> minimize the area of the document view that is invalidated. To force
> invalidation of the document view, use -[NSView setNeedsDisplayInRect:].",
> macos(10.0, API_TO_BE_DEPRECATED));
>
> The way I read that is that the clip view now always behaves as if
> copyOnScroll is YES. So even though you have it set to NO, the scroll/clip
> view will behave as if it was true. That may be your problem here and
> explain the difference in behavior for you between Mojave and Cataline. Good
> luck.
>
> —Rob
>
>
>
>> On Dec 14, 2019, at 12:20 PM, Gary L. Wade via Cocoa-dev
>> <email@hidden> wrote:
>>
>> I see from your personal web site you know Hebrew. Is it possible the
>> affected/non-drawing pages contain some RTL text while those that don’t only
>> contain LTR? I have seen some bugs with RTL text within NSTextView where the
>> text was/wasn’t drawing in a similar manner. Do you operate at a CoreText
>> level?
>> --
>> Gary L. Wade
>> http://www.garywade.com/
>>
>>> On Dec 14, 2019, at 6:17 AM, Redler Eyal via Cocoa-dev
>>> <email@hidden> wrote:
>>>
>>> Hi All,
>>>
>>> I'm getting reports from users complaining about a strange display issue on
>>> Catalina with my app.
>>> My app is a word-processor (not based on the cocoa text system) whose main
>>> display shows the pages of the document. Every page is a separate view and
>>> all the pages are subviews of one big view which resides inside a scroll
>>> view.
>>>
>>> The problem is that when with some documents, sometimes, when the user
>>> scrolls down the document, some pages are not drawn or even partially
>>> drawn. When the user clicks the place where the page is supposed to appear,
>>> it shows up.
>>> Another interesting bit is seems that while the scroll view background is
>>> drawn, the document views (the view containing the page views) drawRect is
>>> not called or at least not taking effect, I can tell because the pages on
>>> this view cast a shadow which is drawn by drawing blank squares on the
>>> document view with a transparency layer.
>>> Last bit of info, copiesOnScroll set to NO for this view and I see that
>>> this property is deprecated on Catalina.
>>>
>>> So far I'm struggling with this for a couple of weeks, I wasn't able to
>>> reproduce this at all on my machine.
>>> I'm really desperate for an answer and while I'm not expecting anyone here
>>> to provide me with one (wouldn't object, of course :-)) I would love if
>>> people reading this might try to speculate to the causes of this or perhaps
>>> if you have any direction as to what to test on my users machines in order
>>> to be able to reproduce this.
>>>
>>> Thanks
>>>
>>> Eyal Redler
>>> ------------------------------------------------------------------------------------------------
>>> "If Uri Geller bends spoons with divine powers, then he's doing it the hard
>>> way."
>>> --James Randi
>>> www.eyalredler.com
>>
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