RE: Gray background behind app windows?

Begin forwarded message:

> From: Christiaan Hofman <[email protected]>
> Date: September 19, 2009 3:57:42 PM EDT
> To: Duncan Champney <[email protected]>
> Cc: [email protected]
> Subject: Re: Gray background behind app windows?
>
>
> On Sep 19, 2009, at 21:12, Duncan Champney wrote:
>
>>
>> On Sep 18, 2009, at 3:00 PM, [email protected] wrote:
>>
>>> From: Duncan Champney <[email protected]>
>>> Date: September 18, 2009 2:18:39 PM EDT
>>> To: [email protected]
>>> Cc: Steve Sheets <[email protected]>
>>> Subject: Gray background behind app windows?
>>>
>>>
>>> Folks,
>>>
>>> Apps like Photoshop (PS) used to have an option to blank out the  
>>> desktop behind their windows to a flat gray. That reduced visual  
>>> clutter so artists could focus on the app's windows.
>>>
>>> I have Photoshop CS3, not CS4 (I tend to update every other time  
>>> to try to save a little money) so I don't know how it works in  
>>> CS4, but in CS3 under Leopard, it looks like PS turns the document  
>>> window into a "super window" that fills the whole screen and has  
>>> gray borders all the way around.
>>>
>>> Our company is working on rewriting a legacy OS 7/8/9/ app for OS  
>>> X (>= 10.5), and the legacy app has the option to blank out  
>>> everything behind the app's windows to dull gray.
>>>
>>> Does anybody know a way to do this in OS X without either going to  
>>> full-screen mode (and losing Cocoa's support for document windows,  
>>> tool palettes, etc.) or turning the front  document into a monster  
>>> that takes up the whole screen, with the content placed in a  
>>> resizeable view in the middle? That's doable, but less elegant  
>>> than the gray background old OS 9 apps used to use, and doesn't  
>>> allow the user to see more than one document window at a time.
>>>
>>>
>>>
>>> Thanks in advance,
>>>
>>> Duncan C
>>> WareTo LLC
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> From: Kyle Sluder <[email protected]>
>>> Date: September 18, 2009 2:56:29 PM EDT
>>> To: Duncan Champney <[email protected]>
>>> Cc: [email protected], Steve Sheets <[email protected]>
>>> Subject: Re: Gray background behind app windows?
>>>
>>>
>>> On Fri, Sep 18, 2009 at 11:18 AM, Duncan Champney  
>>> <[email protected]> wrote:
>>>> Does anybody know a way to do this in OS X without either going to
>>>> full-screen mode (and losing Cocoa's support for document  
>>>> windows, tool
>>>> palettes, etc.) or turning the front  document into a monster  
>>>> that takes up
>>>> the whole screen, with the content placed in a resizeable view in  
>>>> the
>>>> middle? That's doable, but less elegant than the gray background  
>>>> old OS 9
>>>> apps used to use, and doesn't allow the user to see more than one  
>>>> document
>>>> window at a time.
>>>
>>> Create a screen-sized NSWindow and set its level using -[NSWindow  
>>> setLevel:].
>>>
>>> --Kyle Sluder
>>>
>>>
>>
>>
>> Kyle,
>>
>> What level should I use? I would want the gray window to be behind  
>> all of my app's other windows, but in front of other apps and in  
>> front of the desktop. I could not find a level value for setLevel  
>> that would do what I needed. I tried most of the different  
>> available level settings, but no luck.
>
> First of all: just think. Most windows are at NSNormalWindowLevel,  
> and utility windows etc are at NSFloatingWindowLevel. So it should  
> be obvious that you can't just get what you want by simply setting  
> the window level of the gray background window. You should move both  
> this window and all your apps window to a higher level, at least  
> higher than NSFloatingWindowLevel.
>
> But you have to be careful about that. Certainly it's a bad idea to  
> move anything higher than the Force Quit window (which IIRC is  
> usually placed at NScreensaverWindowLevel, though this is buggy on  
> 10.5.x).
>
> There is no clear cut answer, it really depends on how important it  
> is which other windows should be covered. It is not necessarily true  
> that it MUST cover all other app's windows. Remember, you're not a  
> screen dictator, users may find it very rude when you completely  
> prevent other apps from becoming visible. In most situation in fact  
> the best is to simply use NSNormalWindowLevel, but then you probably  
> want to make sure all your apps windows are moved to the front when  
> your app becomes active.
>
>>
>> Right now I am working on creating a screen-sized window with  
>> styleMask: NSBorderlessWindowMask, at the default level for my app,  
>> then using -orderBack to put it behind my other app windows.
>>
>> The problem with that is that if I click on the gray window, the  
>> system brings it in front of my other app windows. I tried  
>> overriding NSWindow's -mouseDown method and having that method do  
>> nothing, but the system still brings the gray window to the front.
>>
>> How would I get the system to ignore mousedowns in the window so it  
>> does not get moved to the front?
>>
>>
>> Duncan
>
> You probably want to override canBecomeKeyWindow and  
> canBecomeMainWindow to return NO, and you may also want to use  
> setIgnoresMouseEvents:.
>
> Christiaan
>

Christiaan,

Thanks for your suggestions.

I didn't know much about window levels until somebody else suggested  
using that approach. After reading about setLevel and experimenting  
with it, I concluded that it wasn't going to do what I needed without  
doing something like you suggested, raising the level of all my app's  
windows. That seems like it is too likely to cause unwanted side- 
effects.

I really want my gray window to be at the normal window level, but  
always be the LAST window at that level. If I could place it using  
orderLast, then get it to swallow mouse events, I should get exactly  
the effect I am after.

I am creating the window as styleMask: NSBorderlessWindowMask, which  
causes the window to not have a title bar. According to the  
documentation on canBecomeKeyWindow and canBecomeMainWindow, the  
default version of those methods returns false for windows that don't  
have a title bar.

I just tried using setIgnoresMouseEvents: TRUE. It keeps the window  
from responding to mouse events, but it causes it to become  
transparent to mouse events. If I click on the gray area, the mouse  
click passes through my app and brings up whatever other app is hidden  
behind my gray window.

I would have thought that implementing a do-nothing mouseDown method  
for my custom window sub-class would do the trick. It looks like the  
system is handling the click first, doing window ordering, and THEN  
passing the event to my window.

I need some way to tell the system not to bring my window to the front  
when the user clicks on it.


Regards,

Duncan
WareTo