Java rounding the results of a division when it shouldn't be

Question

So I have some code for scaling graphics to the size of a users screen by dividing the size of an \'Ideal\' screen by the size of the users screen. Hers is a code snippet of wha

Answer 1

ui.getWidth and ui.getHeight() returns you int and when you are performing operation on int it returns you int again. So convert your int value to Double.

Double    scaleFactorWidth = new Double(2880) / new Double(ui.getWidth());
Double    scaleFactorHeight = new Double(1800) / new Double(ui.getHeight());

Check below sample,

public static void main(String[] args) {
            Double scaleFactorWidth =  new Double(2880) /  new Double(1024);
            Double scaleFactorHeight = new Double(1024) / new Double(600);


            System.out.println("Scale factors are: "
                    + Double.toString(scaleFactorWidth) + " "
                    + Double.toString(scaleFactorHeight));

            Double textScale = (scaleFactorWidth + scaleFactorHeight) / 2;

            System.out.println("Text scale is: " + Double.toString(textScale));
        }

output:

Scale factors are: 2.8125 1.7066666666666668
Text scale is: 2.2595833333333335

Answer 2

If you're talking about this GameContainer class, getWidth() and getHeight() return an int.

So you have to cast it as double

scaleFactorWidth = (double)2880 / ui.getWidth();
scaleFactorHeight = (double)1800 / ui.getHeight();

Answer 3

In these lines

scaleFactorWidth = 2880 / ui.getWidth();
scaleFactorHeight = 1800 / ui.getHeight();

The calculation itself is Integer-based (according to the later calls of Integer.toString()). Just the result is then casted to double.

Use this code instead, in order to have the actual computation use double values:

scaleFactorWidth = 2880.0 / ui.getWidth();
scaleFactorHeight = 1800.0 / ui.getHeight();

or

scaleFactorWidth = 2880.0 / (double)ui.getWidth();
scaleFactorHeight = 1800.0 / (double)ui.getHeight();

Answer 4

Cast it to Double.

   scaleFactorWidth = (Double)2880 / ui.getWidth();
    scaleFactorHeight = (Double)1800 / ui.getHeight();