Can this code look cleaner in C#?

Question

I have a C programming background and I am used to doing ugly things.

Is there a more elegant/readable way to do this scaling operation in C#:

ImageProcessing.Resize(original, 80, (int)((float)original.Height * (80f / original.Width)));

Where "original" is the .Net Image class and Image.Width and Image.Height are thus integers.

These questions are better asked over at http://codereview.stackexchange.com/ — Ron Beyer, Apr 30 '15 at 01:00
@RonBeyer One-liners are typically quite poor fits for [codereview.se]. — nhgrif, Apr 30 '15 at 01:01
In either case, here's what you ask yourself, 1) Does it work? 2) Can my coworker read it and understand it? 3) Could it be refactored easily? I'm guessing #3 is yes, by breaking out the variables individually, the compiler will optimize it away anyway so don't be afraid to use more code to make things cleaner, especially with simple calculations like this. — Ron Beyer, Apr 30 '15 at 01:03

Timothy Shields · Accepted Answer · 2015-04-30T01:14:43.240

3

Regular division followed by the floor operation (cast to int) is equivalent to integer division. Multiplication and division are left-associative. Therefore you can use this much shorter code:

ImageProcessing.Resize(original, 80, 80 * original.Height / original.Width);

To convince you, suppose Width and Height are 300 and 200, respectively. Then your code will do this:

(int)(200f * (80f / 300f)) = (int)(200f * 0.2666...) = (int)(53.3333...) = 53

And my code will do this (where / denotes integer division):

80 * 200 / 300 = 16000 / 300 = 53

edited Apr 30 '15 at 01:14

answered Apr 30 '15 at 01:07

Timothy Shields

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Integer division in C# returns an int. For the scaling code to work, you need to do float division. http://stackoverflow.com/questions/10851273/why-integer-division-in-c-sharp-returns-an-integer-but-not-a-float – John Shedletsky Apr 30 '15 at 01:10
Maybe I should have added that original is of type Image and thus .Width and .Height are ints. – John Shedletsky Apr 30 '15 at 01:11
@JohnShedletsky Take a closer look at what I proposed and try it out. The multiplication happens before the division, so the scaling will in fact work fine. – Timothy Shields Apr 30 '15 at 01:11
Oh I see. I can never remember the association direction or operator precedence rules. – John Shedletsky Apr 30 '15 at 01:13
Yours is better in a tight loop as well. Probably way faster (10x?) to avoid the floating point math and the typecast. – John Shedletsky Apr 30 '15 at 01:24

score 0 · Answer 2 · answered Apr 30 '15 at 01:22

If you want to change code (which looks ok): Since "w/h" is aspect ratio separately computing it may produce more self-documenting code:

var aspectRatio = original.Width / (float)original.Height;
int newWidth = 80;
ImageProcessing.Resize(original, newWidth, (int)(newWidth / aspectRatio));

Can this code look cleaner in C#?

2 Answers2