Re: Slow application startup when using a theme

[Richard Frith-Macdonald]

On 10 Jan 2012, at 09:12, Fred Kiefer wrote:

> On 10.01.2012 09:14, Richard Frith-Macdonald wrote:
>> 
>> On 10 Jan 2012, at 04:54, Eric Wasylishen wrote:
>> 
>>> I didn't like the current approach either…  I just committed a
>>> rewrite of how theme images are handled which gets rid of theme
>>> proxies entirely, and eliminates the code in -[GSTheme activate]
>>> and -[GSTheme deactivate] which were setting/restoring images.
>>> 
>>> Now, when a name is set on an NSImage instance, it also subscribes
>>> to the theme change notification. When an NSImage receives this
>>> notification, it does the name-to-path lookup again that +[NSImage
>>> imageNamed:] did, and reloads itself (discarding all reps) if the
>>> path has changed.
>>> 
>>> It's a fairly major change but I tested Gorm, GSTest, SimpleAgenda,
>>> and tried switching between the GNUstep default theme, Neos, and
>>> Etoile's Nesedah theme while the apps were running, and all images
>>> seemed to update properly.
>> 
>> The proxy approach was done so that cached references to images and
>> copies of images would change when the theme changes, and we wouldn't
>> need to go through the codebase changing all applications to either
>> refrain from caching/copying named images, or be theme aware and
>> refresh cached images when a theme changes.
>> 
>> Unless you've done something I missed, this rewrite will have broken
>> theming for any code which caches images rather than fetching them by
>> name each time it needs to draw ... but this may not be an issue any
>> more (we may have rewritten all such code to be theme aware by now)
>> in the GUI, and being realistic, there are probably few enough gui
>> apps that copy system images in existence, that we can ignore them.
>> But ... it would make sense to go through the GUI  code and look for
>> any remaining cases where the change will have broken things (or just
>> wait for bug reports I suppose).
> 
> Richard, you may be missing the whole point of Eric's change. When you made 
> that proxy image change and I started criticising it we both didn't see the 
> obvious, that Eric easily spotted: NSImage itself is already a proxy!
> His change now reuses the same NSImage object when the theme changes, but 
> stores the new NSImageReps in it. There still may be some minor flaws in the 
> code, but the basic concept sounds valid for me. The only thing about it that 
> I cannot stand is that I did not see it myself :-)

Yes ... I missed the fact that this change effectively makes an image into a 
proxy by having it completely reinitialise itself.  That certainly copes with 
all those cases where people have retained instances of the system image.  It's 
great.