Lewis <g.k...@gmail.com.dontsendmecopies> wrote:
> In message <
1l6xi48.ujui3eea63opN%dem...@actrix.gen.nz>
> David Empson <
dem...@actrix.gen.nz> wrote:
> >The effect is worst for non-retina models, because the graphical
> >objects for retina displays are four times larger than those for
> >non-retina displays (due to having four times as many pixels in the
> >same area).
>
> That would be true if graphics were stored as bmp files or something
> uncompressed. It is not at all true for the png or jpg files that are
> actually used. A graphic is not necessarily 4x larger in file size just
> because it is 4x larger in pixel count.
True, I was generalising for the worst case and should have said "up to
4x larger". There is still wasted duplication of graphical resources,
because there are both standard and 2x versions of most graphical
objects, only one of which gets used on a particular device. The 2x
graphics will almost always require more space than the 1x graphics,
therefore non-retina devices are worse off for wasted storage space than
retina devices.
> > If the app is written to run natively on the iPhone and iPad, the
> > wastage is even worse, because it may need to include four instances of
> > each graphical object: for non-retina iPhones, retina iPhones,
> > non-retina iPads and retina iPads. (Apps with separate versions for the
> > iPhone and iPad avoid this problem.)
>
> iOS 7 apps will be able to drop the non-retina iPhone and non-Retina iPad
> sizes.
>
> But then again, the retina iPhone and non-retina iPad are the same size,
> so no need for separate graphics.
On iOS 6 or earlier, a non-retina iPad running an iPhone-only app uses
non-retina iPhone graphics, even if the app contains retina graphics and
is operating in 2x mode. It is horribly pixelated in 2x mode.
Will that be changing in iOS 7? Apple hasn't mentioned anything that I
noticed, so if there is such a change I expect it is under NDA.
If it is the case that the iPad mini and iPad 2 will use retina graphics
for iPhone-only apps and always run the app in 2x mode, then iPhone-only
apps which require iOS 7 could drop all non-retina graphics objects.
> > In a few years
>
> months?
Years. iOS 7 supports the iPad 2 and iPad mini, which have a non-retina
display, therefore native iPad apps running on those devices which
require iOS 7 must still include non-retina graphics.
iOS 8 (late 2014) might still need to support at least the iPad mini,
depending on how long Apple keeps selling a non-retina model after iOS 7
is released. Therefore apps which require iOS 8 might still need to
include non-retina iPad graphics.
iOS 9 (late 2015) is very likely to only work on devices with retina
displays, therefore apps which require iOS 9 will almost certainly be
able to drop non-retina iPad graphics.
> > this should be less of a problem because a future iOS
> > version will drop support for all older models which don't have a retina
> > display, therefore apps which require that future iOS version will no
> > longer need to include non-retina graphics.
>
> > That can't happen as soon as iOS 7, because iOS 7 will support the iPad
> > 2 and iPad mini, which don't have a retina display.
>
> But have the same resolution as the iPhone 4 and 4S.
>
> > In theory, a universal (native on iPhone and iPad) app which required
> > iOS 7 could drop the iPhone non-retina graphics, because iOS 7 doesn't
> > run on any iPhone or iPod Touch models with a non-retina display, and
> > the app will never display those graphical objects when running on an
> > iPad. It would still need graphical objects for retina iPhone,
> > non-retina iPad and retina iPad.
>
> Nope, just retina iPhone and retina iPad.
And non-retina iPad. The native user interface of iPad apps running on
an iPad mini or iPad 2 under iOS 7 will not be able to use retina
graphics.
Universal apps running on an iPad do not use the iPhone user interface,
so any iPhone graphics (retina or non-retina) in the app are ignored on
the iPad.
--
David Empson
dem...@actrix.gen.nz