Re: ScreenSaverView with multiple displays
Re: ScreenSaverView with multiple displays
- Subject: Re: ScreenSaverView with multiple displays
- From: "Douglas A. Welton" <email@hidden>
- Date: Thu, 27 Jan 2005 12:06:05 -0500
Patrick,
Are you comparing the NSRect passed to -initWithFrame: with your known list
of screen frames? I haven't tried this myself, but it would make sense that
the -initWithFrame: argument would match up.
Also, since all of the screen share the same Cartesian coordinates system,
would it not be correct to assume that if your drawing coordinates are not
found on the main screen (i.e., NSPointInRect() )that you must be drawing on
one of the secondary screens?
curiously,
douglas
on 1/26/05 11:46 PM, patrick at email@hidden wrote:
> To follow up on the problem of screen savers and multiple screens, I'm
> wondering if you or someone can help me wrap my head around something:
>
> My screen saver is written such that I maintain state information
> about where I am on the screen for the next iteration of
> animateOneFrame(). I currently am only drawing to the main screen
> (using the isMenuBarScreen() method you so kindly helped me with)
> because I haven't figured out a good way to reliably tell to which
> monitor I am drawing. Well, the current way with isMenuBarScreen works
> great for two monitors, but not three or more. While it probably is
> pretty uncommon for someone to have three or monitors, it bothers me
> that I can't solve this problem for n number of monitors.
>
> I would like to create a struct of some sort to store the state
> information for each screen to be put into an array, indexed one for
> each screen. While I can get an array of screens using [NSScreen
> screens], and I [think] I can get the NSScreen by doing [[self window]
> screen], should it work if I were to test for the current screen by
> doing:
>
> NSScreen *currentScreen = [[self window] screen];
> NSArray *screens = [NSScreen screens];
>
> int i;
> int size = [screens size];
> int currentScreenIndex = -1;
>
> for (i = 0; i < size; i++)
> {
> if ((NSWindow)[screens objectAtIndex:i] == currentScreen))
> {
> currentScreenIndex = i;
> }
> }
>
> // go on to get my state struct out of a array indexed one-for-one
> with the [NSScreen screens] array...
>
> Patrick
>
>
> On Wed, 29 Dec 2004 16:19:02 -0800, Steve Christensen <email@hidden> wrote:
>> How about something like this?
>>
>> 1. Add a BOOL _isMenuBarDisplay to your screensaver view class.
>>
>> 2. Override -initWithFrame: and -initWithFrame:isPreview:.
>> In each, call the super's method, then
>> if -isPreview, set _isMenuBarDisplay to true, else check if
>> frameRect has
>> the same bounds as the main screen and set _isMenuBarDisplay
>> accordingly.
>>
>> 3. Override -animateOneFrame (and -drawRect: ?), check
>> _isMenuBarDisplay and
>> do the appropriate thing.
>>
>> This assumes that the view bounds are in global coordinates and are
>> aligned with individual screens, but this is just a guess since I
>> haven't yet written a screensaver. :-) If it works, it should get you
>> away from messy issues like the order in which the views are
>> initialized.
>>
>> As for counting the number of screens, how about:
>>
>> unsigned int screenCount = [[NSScreen screens] count];
>>
>> And finding the menu bar screen:
>>
>> - (BOOL) isMenuBarScreen
>> {
>> NSArray* listOfScreens = [NSScreen screens];
>>
>> if ((listOfScreens != nil) && ([listOfScreens count] > 0))
>> return NSEqualRects([self frame], [listOfScreens
>> objectAtIndex:0]);
>>
>> return false;
>> }
>>
>> steve
>>
>>
>> On Dec 29, 2004, at 3:09 PM, patrick wrote:
>>
>>> I'm creating a screensaver, and I would like to be able to draw
>>> something different on displays other than the primary. Through trial
>>> and error, I've learned that initWithFrame() gets called for each
>>> display, although it doesn't seem like any useful information is
>>> passed into initWithFrame() or animateOneFrame() to help the developer
>>> know which display is being used.
>>>
>>> By using a counter in my ScreenSaverView and incrementing it each time
>>> initWithFrame() is called (where isPreview is false) I am able to
>>> count how many displays there are, and it seems like animateOneFrame()
>>> is called in order of display: animateOneFrame() for display 1,
>>> animateOneFrame() for display 2, and then back to 1 again, etc. So by
>>> using another counter, I can [sort of] keep track of to which display
>>> I'm drawing, though it doesn't seem like that great a way of doing
>>> this, nor does it seem that foolproof.
>>>
>>> Does anyone have any suggestions as to a better way of knowing a) how
>>> many displays there are to begin with, and b) a good way in
>>> animateOneFrame() to tell which display is being used?
>>>
>>> Many thanks,
>>>
>>> Patrick
>>
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