How To Calculate Android Screen Aspect Ratio Mathematically

One of the device screen properties that Android lets an app query is it's aspect ratio. In the examples that I have seen this property seems to have only two values - long and not

Solution 1:

DisplayMetricsmetrics= context.getResources().getDisplayMetrics();
floatratio= ((float)metrics.heightPixels / (float)metrics.widthPixels);

Solution 2:

To find ration in (16:9) you need to find the GCD and then divide both numbers by that.

intgcd(int p, int q) {
    if (q == 0) return p;
    elsereturn gcd(q, p % q);
}

voidratio(int a, int b) {
   finalintgcd= gcd(a,b);
   if(a > b) {
       showAnswer(a/gcd, b/gcd);
   } else {
       showAnswer(b/gcd, a/gcd);
   }
}

voidshowAnswer(int a, int b) {
   System.out.println(a + " " + b);
}

After this just call ratio(1920,1080);

Solution 3:

I think i am very much late for this answer but still for the people who want to know, the answer is:

if(screen_width > screen_height) 
{
    aspectRatio = screen_width / screen_height;
} 
else 
{
    aspectRatio = screen_height / screen_width;
}

Solution 4:

This is an old question, but none of the proposed answers was getting me quite the right ratio. After trying this out, I was able to get the right aspect ratio (e.g., Pixel 3a is 18.5/9 = 2.0555):

Kotlin:

val aspectRatio = window.decorView.height.toFloat() / window.decorView.width.toFloat()

Java:

float aspectRatio = ((float) getWindow().getDecorView().getHeight()) / 
    ((float) getWindow().getDecorView().getWidth())

Solution 5:

...property seems to have only two values - long and notlong. I am trying to reverse engineer the logic being used by Android to classify a device as having one of the two aspect ratios.

For the record, there's no need to reverse engineer, just see https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/content/res/Configuration.java

// Is this a long screen?if (((longSizeDp*3)/5) >= (shortSizeDp-1)) {
            // Anything wider than WVGA (5:3) is considering to be long.
            screenLayoutLong = true;
        } else {
            screenLayoutLong = false;
        }

So basically Android takes screen sizes in DP and the result is:

• long - screen with aspect ratio > 1.667 (5:3) - i.e. > WVGA
• notlong - screen with aspect ratio <= 1.667 (5:3) - i.e. <= WVGA

---

Example - Nexus 4 - 384 x 640 dp (5:3): long edge in dp: 640 short edge in dp: 384

Maths: 640 * 3 / 5 = 384 384 >= (384 - 1) -> false -> notlong