Ruler Custom View

Question

I created a ruler that looks like a typical ruler in school. What i want to know is, what kind of formula is this "int size = (i%2.5==0) ? 2000 : 13;". I have successfully solved in creating this view but i don't really know how this formula works. Can anyone explain?

public class ColorRulerView extends View {
    Paint paint = new Paint();
    static final private float pxinch = 500 / 67.f * 25.4f / 16;
    float width, height;

    public ColorRulerView(Context context, AttributeSet foo) {
        super(context, foo);
        setBackgroundColor(Color.TRANSPARENT);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(0);
        paint.setAntiAlias(false);
        paint.setColor(Color.WHITE);
    }

    public void onSizeChanged(int w, int h, int oldW, int oldH) {
        width = w;
        height = h;
    }

    public void onDraw(Canvas c) {
        for (int i = 0; ; ++i) {
            float x = i * pxinch;
            if (x > 5000) {
                break;
            }
            int size = (i%2.5==0) ? 2000 : 13;
            c.drawLine(x, 2, x, size, paint);
        }
        super.onDraw(c);
    }
  }

Answer 1

The statement

int size = (i%2.5==0) ? 2000 : 13 

is a ternary operation.

lets break this down:

(i % 2.5) : this will produce the reminder when the value of i is divided by 2.5. So, if

i = 3, 3 % 2.5 = 0.5

i = 4, 4 % 2.5 = 1.5

assume i = 3, the result is 0.5 which is not equal to 0. So, size will be 13.

whenever the condition (i % 2.5 == 0) is true, size is assigned a value 2000 else, it is assign 13.

value that can make this condition true are 5, 10, 15 etc.