The short version: Datagrid.... GOOD! Bob S
> On Apr 2, 2017, at 23:58 , Mark Waddingham via use-livecode > <use-livecode@lists.runrev.com> wrote: > > On 2017-04-02 19:07, Richmond Mathewson via use-livecode wrote: >> The problem, such as it is, is that the Unicode specifications have >> 128 * 8703 slots for glyphs (= a big number my mind cannot cope with) >> and the display in my "CHAR REF" stack is set up to cope with 128 >> glyphs a go: hence 8703 buttons. >> Of course I could be racist and leave out the Chinese ideograph slots >> (= about 70%) . . . > > You'd probably be okay with 8703 buttons (were there not a co-ordinate > magnitude limit), but certainly not with 128*8703 buttons. > > To give some context... > > Each button takes up at least 128 bytes in memory, so: > > 8703 buttons is about 1.4Mb - which isn't too bad > > 8703*128 buttons would be about 150Mb - which is substantially more > > Admittedly, neither of these will 'break the bank' in terms of memory > availability, even on machines of a G3 Mac vintage, however just storing the > representation of such things in memory is not the only issue. The engine has > to do things like: > > - render all the controls on the card > > - perform hit testing when the user clicks or interacts with the card > > - search for controls when you reference them in script > > Rendering requires a linear back to front scan of each control, painting each > one which is within the visible rect of the window the card sits in. This > means that if you have 8703*128 buttons it will need to perform that many > steps to render. Additionally, whenever a small amount changes, it needs to > do this again - as any one control *could* have been moved or intersect with > the area which has changed (and thus require rendering). > > Hit testing is similar, although the process is from front to back, and stops > as soon as a control says it is the target of the mouse / user interaction > event. > > The third case, is the killer though. Looking up a control by name or by > later requires (on average) number of controls on card / 2 steps to perform. > If you use the (short) id, then there is a per-stack cache which makes the > lookup take 1 step if it has been looked up before but the normal number of > steps if it has not. > > In general, we'd never advise using so many controls on a single card - and a > data-oriented approach which is what others have suggested is generally the > best approach in this case. i.e. Update the content of a small set of buttons > as the user browses through the list. > >> I wonder if that limit is "cast in stone" or the Livecode people could >> expand it? > > Currently engine controls are limited to 16-bit quantities for co-ordinates - > which means a range of -32768 to 32768. The underlying rendering library we > use (libgraphics), however, uses floats (32-bit real numbers which given an > integer range up to around 2^24). So, updating the engine to use floats or > similar in its co-ordinates for controls is certainly possible, just not a > task we've undertaken yet. > > Warmest Regards, > > Mark. > > -- > Mark Waddingham ~ m...@livecode.com ~ http://www.livecode.com/ > LiveCode: Everyone can create apps _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
