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 > > > ---------------------------------------------------------------------- > > > For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
