How to get the aspect ratio of an image?

Yes, this is correct – though it unnecessarily uses two divisions instead of one division and a multiplication, adjusted height = <user-chosen width> * original height / original width.

The corresponding formula for the adjusted width is adjusted width = <user-chosen height> * original width / original height, or if you want to do it your way, adjusted width = <user-chosen height> * aspect ratio, with aspect ratio calculated as before.

Yes. You said you want the aspect ratio of the adjusted image to be the same as the aspect ratio of the original equation, so you want

$\frac{\text{adjusted width}}{\text{adjusted height}} = \frac{\text{original width}}{\text{original height}}$

Multiplying both sides of the equation by the adjusted height, you get

$\text{adjusted width} = \frac{\text{original width}}{\text{original height}} \cdot \text{adjusted height}$

Then, dividing both sides of the equation by $\frac{\text{original width}}{\text{original height}}$, you get

$\text{adjusted width } / \frac{\text{original width}}{\text{original height}} = \text{adjusted height},$

which is the formula you suggested!

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So, how do you get the adjusted width when the user adjusts the height field? The answer is hidden in the reasoning above! Can you find it?

Yes, this is the formula: Aspect Ratio = Width / Height for example:

• Width = 300

  - Height = 150

• Aspect Ratio = 2/1 (or 2:1)

if we want to calculate new object size, you need to have a new object dimension like height, or width to calculate remaining one preserving aspect ratio. let's say we have:

• New Height = 300

  - Aspect Ratio = 2/1

• New Width = ? Knowing that, or fractions should look like that: 300 / New Width = 2 / 1 => New Width = 150 Or you can calculate your new measurements using this online aspect ratio calculator that do the job for you and can calculate: aspect ratio, number of pixels (if is image) and new dimensions for objects or images keeping its aspect ratio.