adjusting screen brightness

[ecume]

I assume you need to jailbreak to get access to system controls like this, but I'll throw this out there in case someone has discovered a handy solution...

[lapse]

I believe the application 'Light' was removed from the store for messing with the screen brightness.

[SkylarEC]

Yes, Apple will reject your app if you mess with the brightness. Although, if you still want to do it, you'd get the current brightness like this:

-(void)getBacklightLevel;{
	NSNumber *bl = (NSNumber*) CFPreferencesCopyAppValue(CFSTR("SBBacklightLevel" ), CFSTR("com.apple.springboard"));
	 previousBacklightLevel = [bl floatValue]; //a variable to store the previous level so you can reset it.
	 [bl release];
}

And to set the backlight level, add this line

GSEventSetBacklightLevel(newLevel); //The new level: 0.0 - 1.0.

In order for this to work, you will need to include GraphicsServices.h. Depending on where you get your headers, you may need to add the GSEventSetBacklightLevel(float value); method to the headers, else the method won't quite work. [Some have reported kernel panics by not amending the header, but that has not been my experience]

[wuf810]

Originally Posted by SkylarEC

Yes, Apple will reject your app if you mess with the brightness. Although, if you still want to do it, you'd get the current brightness like this:

-(void)getBacklightLevel;{
	NSNumber *bl = (NSNumber*) CFPreferencesCopyAppValue(CFSTR("SBBacklightLevel" ), CFSTR("com.apple.springboard"));
	 previousBacklightLevel = [bl floatValue]; //a variable to store the previous level so you can reset it.
	 [bl release];
}

And to set the backlight level, add this line

GSEventSetBacklightLevel(newLevel); //The new level: 0.0 - 1.0.

In order for this to work, you will need to include GraphicsServices.h. Depending on where you get your headers, you may need to add the GSEventSetBacklightLevel(float value); method to the headers, else the method won't quite work. [Some have reported kernel panics by not amending the header, but that has not been my experience]

wow sorry to raise such as an old thread, but does anyone know if this still works. I can't seem to return the current backlight value anymore (I'm sure it worked once)....its for a private app BTW so no App store violations

TIA, Michael.

[lewis]

Originally Posted by lapse

I believe the application 'Light' was removed from the store for messing with the screen brightness.

I've seen two applications ("Astronomy Flashlight" and "Flashlight.") in the store that adjust the screen's brightness one way or another. They probably don't adjust the system brightness but they seem to have a way to "dim" the screen. Any ideas? It appears possible if (at least) two apps have made it into the store.

[arutad]

Sneaky..!

Originally Posted by SkylarEC

In order for this to work, you will need to include GraphicsServices.h. Depending on where you get your headers, you may need to add the GSEventSetBacklightLevel(float value); method to the headers, else the method won't quite work. [Some have reported kernel panics by not amending the header, but that has not been my experience]

[ftm]

I think Flashlight may just be using different color backgrounds... gray's appear dimmer than whites.

[lewis]

Originally Posted by ftm

I think Flashlight may just be using different color backgrounds... gray's appear dimmer than whites.

Perhaps, but that doesn't explain how "Astronomy Flashlight" works and even if "Flashlight." does just use grays, how does it fade from one color to the gray?

[wuf810]

Originally Posted by lewis

Perhaps, but that doesn't explain how "Astronomy Flashlight" works and even if "Flashlight." does just use grays, how does it fade from one color to the gray?

they don't adjust the backlight levels...all they are doing is adjusting the alpha level of the top (red) view.

[lewis]

Originally Posted by wuf810

they don't adjust the backlight levels...all they are doing is adjusting the alpha level of the top (red) view.

Oh, I see. Thanks.

So does anyone know how to find the GraphicsServices library? I know I won't be able to submit it to the App Store, but I can still use it personally, can't I? I located the GraphicsServices.framework (several, actually), but when I try and expand it there are no headers listed? Did Apple just remove access to this completely or is there something else that needs to be done? TIA.

[wuf810]

Originally Posted by lewis

Oh, I see. Thanks.

So does anyone know how to find the GraphicsServices library? I know I won't be able to submit it to the App Store, but I can still use it personally, can't I? I located the GraphicsServices.framework (several, actually), but when I try and expand it there are no headers listed? Did Apple just remove access to this completely or is there something else that needs to be done? TIA.

check out this link The iPhone SDK: APIs Apple Didn't Want You to Know About | O'Reilly Media

It has all the info you need but its quite complicated if you are new to this sort of stuff.

M.