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: Thu, 19 Dec 2019 16:09:02 +0200
>>
>> OK, I'll try to get the sysdiagnose from my users before submitting. I must
>> say I'm really skeptic regarding the relation with my use of CG. It is not
>> that CG is not used by CT and everything else is also using CG.
>
> CG may not be the issue… and I cannot offer a better suggestion, but when I
> rule out a possibility without proof, it usually turns out that I over look
> the solution to the problem. Good luck!
You're right, and I wasn't ruling it out. I actually sent my user a special
build with an defaults option to turn off page drawing (so the page views are
not doing any drawing CG or otherwise), the issue persists.
I also tried to see this issue while doing remote access using anyDesk, for
some reason, the issue never showed up, when I disconnected, it showed up again.
Eyal
> Sandor
>
>> The way it looks it seems very much related to the scrolling mechanism, the
>> pre-rendered portion is not rendered but for some reason the scrolling
>> mechanism thinks that it is. I really don't see how a core-graphic issue,
>> and certainly not a misuse on my part could cause a view to be partially
>> rendered.
>> BTW, do you think this type of issue is appropriate for a DTS incident?
>>
>>> Here’s the developer release notes for Catalina:
>>> https://developer.apple.com/documentation/macos_release_notes/macos_catalina_10_15_release_notes
>>
>> Thanks. I saw that but I recall that in the past you used to have app-kit
>> specific release notes which were usually more detailed.
>>
>>> As an aside, it would be helpful to know why you chose CG for text
>>> rendering. CT has gotten better with RTL and bidi text, but if you saw
>>> particular issues there, reports about those can help everyone.
>>
>> When I started developing this app (2002), there was no choice other then CG
>> since core text didn't exist and the other technologies didn't support
>> Hebrew and RTL well, if at all. So I wrote my own text engine and this was
>> very good for me commercially as my app was the the first and only
>> word-processor to support Hebrew (and later Arabic) properly on Max OS X. I
>> had a similar experience with OpenType which was not initially supported and
>> that also gave me an edge. As time passed Apple did improve the RTL support
>> and was offering more APIs so theoretically I could have rewritten my code
>> to use the new APIs but in reality I actually did the opposite and relied
>> less on Apple's APIs (for example, parsing 'cmap' tables) because there were
>> always bugs and even regressions which could render my app unusable upon an
>> OS upgrade. Beyond the bugs, I think my RTL is better, or at least as far as
>> I'm concerned as a native Hebrew speaker and having such low-level control
>> over something that is core to my app is essential IMO.
>>
>> Eyal Redler
>> ------------------------------------------------------------------------------------------------
>> "If Uri Geller bends spoons with divine powers, then he's doing it the hard
>> way."
>> --James Randi
>> www.eyalredler.com
>>
>>
>>
>>
>>
>>
>>> Gary L. Wade
>>> http://www.garywade.com/
>>>
>>>>> On Dec 17, 2019, at 2:12 AM, Redler Eyal <email@hidden> wrote:
>>>>
>>>> I am drawing using core graphics. I tried turning copiesOnScroll and this
>>>> didn't seem to help.
>>>>
>>>> I'll gladly write a feedback report but I'm not able to reproduce this so
>>>> I can't give an xcode project that will reproduce this... Isn't that a
>>>> requirement?
>>>>
>>>> BTW, perhaps you know: Are there no release notes for app kit with
>>>> Catalina? All I can find are very general notes without mention of any
>>>> specific API. I could not find, for example, any mention of the
>>>> deprecation of copiesOnScroll and what it means (is is not always on,
>>>> always off etc)
>>>>
>>>> Thanks,
>>>>
>>>> Eyal
>>>>
>>>>> On 16 Dec 2019, at 16:07, Gary L. Wade <email@hidden>
>>>>> wrote:
>>>>>
>>>>> If you’re not involving a higher level class like NSTextView or a medium
>>>>> level one like CoreText, it sounds like you might be going all the way
>>>>> down to CoreGraphics? If so, you might find your disparity between your
>>>>> system and your users in things like retina choice for a particular
>>>>> display and changes with respect to layers, especially things like the
>>>>> copiesOnScroll. If these don’t lead you to a solution where you say, “Oh,
>>>>> I really should’ve done this rather than that,” (20/20 hindsight) then
>>>>> write up a feedback report and add its URL here.
>>>>> --
>>>>> Gary L. Wade
>>>>> http://www.garywade.com/
>>>>>
>>>>>> On Dec 16, 2019, at 1:03 AM, Redler Eyal via Cocoa-dev
>>>>>> <email@hidden> wrote:
>>>>>>
>>>>>> Thanks!
>>>>>> I don't use CoreText or NSTextView. I pretty much ruled out RTL vs LTR
>>>>>> issues since this is showing up in documents containing either and both.
>>>>>> I'm also unable to imagine how some text drawing code could produce such
>>>>>> artifacts as splitting a subview in the middle.
>>>>>> (http://eyalredler.com/stuff/catalina_glitch.png)
>>>>>>
>>>>>> Eyal
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>> On 14 Dec 2019, at 21:20, Gary L. Wade <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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