UPDATE

Viewmat is still working fine on my iPhone]. It was working on my iPad till 
last week. Just noticed that my iPad got auto-updated to iPadOS 15.7 recently 
but my iPhone is still on iOS 15.6.1.

It is highly like that the 15.7 update has somehow screwed with Viewmat???

I will stick with 15.6.1 on the iPhone for the time being so if required I can 
assist in debugging / comparison.


________________________________
From: Programming <programming-boun...@forums.jsoftware.com> on behalf of Ian 
Clark <earthspo...@gmail.com>
Sent: Tuesday, September 20, 2022 4:49 am
To: programm...@jsoftware.com <programm...@jsoftware.com>
Subject: Re: [Jprogramming] Viewmatnot functioning in IOS J

> Since 2014, viewmat generated png format file instead of bmp.

Yes that's true of the JAL addon. But both j701 / j901 for iOS have their
own versions of viewmat, which work in the way I describe.

On Tue, 20 Sept 2022 at 04:40, bill lam <bbill....@gmail.com> wrote:

> Since 2014, viewmat generated png format file instead of bmp.
>
> On Tue, Sep 20, 2022 at 11:34 AM Ian Clark <earthspo...@gmail.com> wrote:
>
> > I confess I'm slightly baffled by Richard's post. AFAIK the value
> returned
> > by the verb: viewmat is undefined, and no meaning can be attached to it.
> > Viewmat works in different ways on different platforms, but when I trace
> > the code of verb: viewmat as defined in line 361 of
> > ~addons/graphics/viewmat/viewmat.ijs it typically returns some variant of
> > empty, EMPTY or i.0 0.
> >
> >
> > So, taking Richard's sample sentences and replacing the argument with y,
> > it's no surprise that:
> >
> >
> >    viewmat y
> >
> > NB. no output
> >
> >
> >    $viewmat y
> >
> > 0 0
> >
> >
> > However while checking this out I've stumbled on the tip of an iceberg.
> > Thank you Richard for alerting me to the fact.
> >
> >
> > The code of Viewmat is involved. It looks as if it's been patched and
> > patched over the years. But whatever the platform, it basically works by
> > generating a bitmap (BMP) file (i.e. having the extension .bmp) and then
> > picking one of a bunch of ways to display it.
> >
> >
> > Both j701 and j901 apps for iOS generate a BMP file. j701 wraps the file
> > path in html code which it then displays using UIKit's (deprecated)
> browser
> > object UIWebView. j901 uses neither UIWebView nor the replacement
> WkWebView
> > to display the BMP file, but instead calls UIKit's image display object
> > UIImageView, which can handle BMP. Or it did once.
> >
> >
> > Apple had recently released updates to several of its systems fixing
> major
> > security exposures. Since then Viewmat *in both j701 and j901* has
> broken.
> > (It was working in both apps in July of this year.)
> >
> >
> > JQt is unaffected. Viewmat still works on a Mac running the latest
> version
> > of Monterey. I'm guessing this is because JQt does not use Apple system
> > code to display the generated BMP. Instead it converts the BMP file
> > contents into an RGB array (a J noun of integer type) and then uses gl2
> > (glpixels) to display it on a Qt-managed canvas.
> >
> >
> > When I copy the BMP file generated by j901 onto a Mac MBA which is still
> > running Big Sur, I can readily display it using Preview – and the icon
> > itself shows a thumbnail of the file contents. But I cannot get a newer
> Mac
> > running Monterey to display the very same BMP. Yet Monterey was able to
> do
> > so back in July, before the recent Apple fixes. It's the same story with
> > iOS. On both platforms Preview now tells me that my BMP file is either
> > corrupt or an unsupported file format.
> >
> >
> > This cannot be a coincidence. It looks as if Apple has simply decided to
> > cancel BMP on the latest versions of Monterey and iOS. But I find it hard
> > to believe. Maybe it's just a bug introduced by Apple in its haste to
> shore
> > up its systems. Or maybe the BMP spec is being more closely adhered-to
> than
> > hitherto.
> >
> >
> > I propose to take the matter up with Apple. J needs BMP, even if Apple
> > doesn't.
> >
> > On Mon, 19 Sept 2022 at 18:24, 'Mike Day' via Programming <
> > programm...@jsoftware.com> wrote:
> >
> > > Confirming Raul’s observations on this iPad running J701 under iOS
> 12.5.5
> > > .
> > > viewmat shows the circle, square and intermediate shape without
> problem,
> > > presumably as required, after copying from the email and pasting into
> the
> > > terminal screen,  so Raul probably typed correctly.  Also, same result
> > > using either @ or @: as he found.  And image is ok running with the
> > > one-liner pasted into the J701 E screen, ie the script-edit page.
> > >
> > > Cheers,
> > >
> > > Mike
> > >
> > > Sent from my iPad
> > >
> > > > On 19 Sep 2022, at 16:52, Raul Miller <rauldmil...@gmail.com> wrote:
> > > >
> > > >> On Mon, Sep 19, 2022 at 11:15 AM Richard Donovan <
> > rsdono...@hotmail.com>
> > > wrote:
> > > >> viewmat((1>+/~@:(4^~(%~i:)))*.1<+/~@:(2^~(%~i:)))666
> > > >> NB. no output
> > > >>
> > > >>   $viewmat((1>+/~@:(4^~(%~i:)))*.1<+/~@:(2^~(%~i:)))666
> > > >> 0 0
> > > >
> > > > This is probably more a topic for the general forum than the
> > > > programming forum, but viewmat also produces a shape 0 0 result in
> > > > jqt. (In jplayground, it produces a shape 1 result which is a single
> > > > space..)
> > > >
> > > > In the jqt viewmat, it pops up a new window with the image. In the
> > > > jplayground viewmat, it produces an inline image (JHS viewmat would
> be
> > > > similar to jplayground's viewmat). On my iphone, running j701, the
> > > > above expression presented the viewmat image at the top of the phone
> > > > (or an expression close to the above -- I hand entered the line, and
> > > > used @ instead of @: which should produce an equivalent result here,
> > > > but the point is that I may have inadvertently changed something
> > > > else...).
> > > >
> > > > To be sure that a viewmat image consistently appears, I copied the
> > > > line into the edit window and ran it from there -- when I did so, the
> > > > edit window was hidden (icon at bottom of region changed from E to J)
> > > > and the session window and the image window appeared.
> > > >
> > > > So... whatever the problem is, it might depend on the version of J
> you
> > > > are running and/or the version of ios that you are running?
> > > >
> > > > I hope this helps,
> > > >
> > > > --
> > > > Raul
> > > >
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