[compiz] switcher patch do disable window list

[David Reveman]

On Sat, 2006-11-11 at 23:49 +0100, Bellegarde Cedric wrote:
> Here is a switcher patch to disable window list:
> 
> It's very useful if you set opacity to 0. Then, window just bring to front one 
> by one while switching. It's much more usable, i think, that small miniatures 
> in a list where you don't see anything.
> 
> While making this patch, a question come into my head, nobody know on 
> compiz.biz and some people are as curious as me.
> 
> Two code example:
> 
> /**********/
>  case SWITCH_SCREEN_OPTION_MIPMAP: 
>  case SWITCH_SCREEN_OPTION_ICON: 
>  case SWITCH_SCREEN_OPTION_MINIMIZED: 
>          if (compSetBoolOption (o, value)) 
>              return TRUE; 
>          break; 
> /**********/
> 
> 
> /**********/
> case SWITCH_SCREEN_OPTION_BRINGTOFRONT: 
>          if (compSetBoolOption (o, value)) 
>          { 
>              ss->bringToFront = o->value.b; 
>              return TRUE; 
>          } 
> /**********/
> 
> At first look, i tell me: "How plugin know that MINIMIZED option had change if 
> we do nothing more than returning TRUE. After looking the code, i saw this:
> 
> ss->opt[SWITCH_SCREEN_OPTION_MINIMIZED].value.b
> 
> So my question is:
> When do i have to directly read CompOption?
> When do i have to add a member to my plugin struct and update it in 
> pluginSetScreenOption() ?

Well, ss->opt[SWITCH_SCREEN_OPTION_MINIMIZED].value.b is the real
storage for the option value. There's usually no reason to keep a copy
of it in another variable, it's just a waste of memory. In some cases a
different value needs to be computed from the actual option value and it
then makes sense to do this when the option is changed. In some cases, I
probably make a copy of option values to clean up the code but that's
just me being lazy and not recommend. It's much better to put a
temporary variable on the stack to clean up code than putting a variable
in the heap allocated screen and display structures.

So I much prefer your first code example.

I should probably fix my code so this is consistent.

-David