iOS get physical screen size programmatically?

Question

Is this possible? I want the number of inches, not the number of pixels. I know it is approximately 160 ppi. But not exactly.

Answer 1

Here's a short method that estimates the device screen size. It's updated as to the latest devices, but may fail on future ones (as all methods of guessing might). It will also get confused if the device is being mirrored (returns the device's screen size, not the mirrored screen size)

#define SCREEN_SIZE_IPHONE_CLASSIC 3.5
#define SCREEN_SIZE_IPHONE_TALL 4.0
#define SCREEN_SIZE_IPAD_CLASSIC 9.7

+ (CGFloat)screenPhysicalSize
{
    if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)
    {
        CGSize result = [[UIScreen mainScreen] bounds].size;
        if (result.height < 500)
            return SCREEN_SIZE_IPHONE_CLASSIC;  // iPhone 4S / 4th Gen iPod Touch or earlier
        else
            return SCREEN_SIZE_IPHONE_TALL;  // iPhone 5
    }
    else
    {
        return SCREEN_SIZE_IPAD_CLASSIC; // iPad
    }
} 

Answer 2

The "formula" I use is

#define IS_iPhone5 ( fabs( (double)[ [ UIScreen mainScreen ] bounds ].size.height - (double)568 ) < DBL_EPSILON )

Answer 3

If it were available it would be in UIScreen or UIDevice but it is not there.

You can infer it from info in Erica's UIDevice-extension and the specs for each device listed here on Wikipedia.

Answer 4

CGFloat scale = [UIScreen mainScreen].scale; CGRect screenRect = [[UIScreen mainScreen] bounds]; CGFloat screenWidth = screenRect.size.width * (scale/100.0f); CGFloat screenHeight = screenRect.size.height * (scale/100.0f);

• scale is persent!

Answer 5

Maybe Jeff Hay's code can be adapted to include iPad Mini. The trick is to get the device's model identifier. The most recent non-retina iPad is "iPad2,4" and the first iPad mini is "iPad2,5". Now all you need to check is if the screen scaling is 1.0 (non-retina)

Although this code is not future-proof, you can always add more rules for model identifiers.

#import <sys/utsname.h>

#define SCREEN_SIZE_IPAD_MINI 7.9

    struct utsname systemInfo;
    uname(&systemInfo);
    if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad && strcasecmp(systemInfo.machine, "iPad2,5") >= 0 [[UIScreen mainScreen] scale] == 1.0)
        return SCREEN_SIZE_IPAD_MINI