Re: Scaling icons

[Bill Haneman <bill haneman sun com>]

Hi Owen:

Thanks for replying to my rather ill-formed concern.

It sounds as though the new proposals are compatible with the
scaling/theming needs of accessibility, and the burden of scalability
lies with theme authors (i.e. they should provide scalable versions of
icons even if they wish to include fixed-size icons for cosmetic
reasons).

One scenario still is unclear to me; if a theme designer has included
both scalable and non-scalable icons, how can we facilitate both the
high-sharpness display that the theme designer presumably desired and
allow low-vision users to forcibly scale those icons in situations where
size is more important than sharpness?   It seems to me that fixed-size
icons inherently defeat accessibility since in order for them to have
meaning, there can't be equivalent scalable versions of the same icons
in the theme.

For instance, if I have a 24x24 icon that I don't want viewed in another
size, it seems that I can't include scalable versions at, say, 48x48 and
18x18 to cover the full range of sizes, because the scalable version(s)
would be then used for all sizes other than 24x24!  

If this is so - i.e. if fixed-size icons are desirable to theme authors,
and using them effectively requires that scalable equivalents are not
available, it seems to me that we have an accessibility problem unless
we provide an option to "force" scaling of icons that the theme has
suggested are "fixed size".  What am I missing here?

regards,

Bill

On Mon, 2003-05-19 at 18:07, Owen Taylor wrote:
> On Mon, 2003-05-19 at 12:50, Bill Haneman wrote:
> > Hi:
> > 
> > This icon scaling discussion is making me a little uneasy.  I admit I
> > haven't been able to follow every turn, but from what I have been able
> > to read carefully so far, I have some concerns regarding accessibility.
> > 
> > Accessibility is a critical customer of icon scaling algorithms, and
> > it's vital that whatever we do respects accessibility requirements. 
> > That means that icon scaling must be _reliable_ and possible regardless
> > of what resolutions icons are available in.  It's important for themes
> > that icons respect size settings, even if the results are "ugly". 
> > Proposing behavior that refuses to resize "scalable" icons seems likely
> > to break accessibility.
> > 
> > Likewise, it's much nicer to allow scaling of icons whether they are
> > "themed" or not; why should it matter whether an icon is "default" ?
> 
> I don't understand this comment; default icons are just part of the
> "hicolor" icon theme and are installed in such a way that they will
> be scaled.
> 
> The main proposals are that 
> 
>  A) If an icon theme author says "this icon should be used for sizes
>     between 18 and 22 pixels" we only scale it if the desired
>     sizes is less than 18 or greater than 22 pixels.
> 
>  B) If icon theme authors install an icon as "fixed size", we
>     honor that.
> 
> > I see potential for regression here.  Please help the accessibility team
> > by thinking through the accessibility use cases here, and recognising
> > that it's important that the gtk-icon-size setting be respected across
> > the board in GNOME applications.  Will the current proposals ensure that
> > this still works?
> 
> An icon theme author could intentionally defeat scaling if they
> wanted to.
> 
> Regards,
>                                                Owen
> 
>