How do I MEASURE a height/width ratio?

[Alaniskindapissed]

So you know that dumb program for losers called GIMP that doesn't even cost a million dollars? Well, it DOES have this one little nifty wherein if I measure a rectangle, it actually AUTOMATICALLY, without the error-prone process of setting tiny four-figure numbers into an off-app calculator, MEAURES THE ASPECT RATIO!

Check it out:

That doesn't happen in PS. But what I'm wondering is if there is ANY way to simply draw OR EVEN select a rectangle for the purposes of measureing a ratio automatically in this way. That's, right I said MEAsURING. Not to crop an image or layer to a specific aspect ratio, not to draw a fill of a predetermined size, or warp an image to a certain dimension, not to rasturbate an object expansion, simply to make a rectangle and KNOW WHAT IT IS AUTOMATICALLY. This would be extremely useful for my purposes. 

Internet is coming up blank.   Any suggestions?

[Chuck Uebele · Accepted solution]

If you actually want to draw a shape to a know aspect ratio, then use the path options in the menu bar.

If you want to measure the aspect ratio, you can use this script that just reduces one of the ratio values to 1.

#target photoshop;
var doc = activeDocument;
var lBounds = doc.activeLayer.bounds
var hor = lBounds[2]-lBounds[0];
var vert = lBounds[3]-lBounds[1];
var max = Math.max(hor,vert)
var min = Math.min(hor,vert)

if(hor>vert){alert(max/min + ':' + min/min)}
else {alert(min/min +':' +max/min)};

[Alaniskindapissed]

I don’t want to draw a shape (as stated), and more importantly I DON’T know the aspect ratio. I mean, yeah, in one particular instance I can figure it out with a calculator, but the point of my post was to avoid that whole thing, as I am often going to have to calculate varying, odd ratios (1.34:1, 2.7:1, 1.91:1 for instance) for different projects and I’d rather not have to run equations on my own when the computer is can do it faster and more accurately.

[Alaniskindapissed]

Uhh no- actually. That script is perfect. Sorry! And thanks!

[jackdaw_1066]

This doesn't work for me. im using PS 2023

[Chuck Uebele]

Did you read the second part of my post where the script will measure for you and display the results, so that all you have to do is copy them?

[Stephen Marsh]

From my previous explorations of aspect ratio, there are at least three different ways to express the ratio. Take the following 1920x1080 canvas:

However, it is not always that easy, different input can create some "interesting" output:

Dimensions: 153 x 92 pixels

Aspect Ratio:

1.66:1 / 3.32:2 / 6.64:4 (Basic)

153:92 (GCD)

5:3 (Farey)

16:9 (Adobe Bridge)

[gener7]

I checked your blog, Stephen and I see you had to pull the code for your Document Info script. Can you post it here?

[Stephen Marsh]

Sure, I’ll update this placeholder:

#target photoshop
//stackoverflow.com/questions/1186414/whats-the-algorithm-to-calculate-aspect-ratio-i-need-an-output-like-43-169
var savedRuler = app.preferences.rulerUnits;        
app.preferences.rulerUnits = Units.PIXELS;
function gcd(a, b) {
    return (b == 0) ? a : gcd(b, a % b);
}
var w = app.activeDocument.width.toString().replace(' px', '');
var h = app.activeDocument.height.toString().replace(' px', '');
var r = gcd(w, h);
var mp = w * h / 1000000
var pix = w * h
var ppiRes = app.activeDocument.resolution;
var ppcmRes = ppiRes/2.54
var ratio = w / h
var docName = app.activeDocument.name;
var wMetric = w / 72 * 2.54
var hMetric = h / 72 * 2.54
var wInches = w / 72
var hInches = h / 72
/////////////////////////////////////////////////////////////////////
    var doc = app.activeDocument    
    var w = doc.width.toString().replace(' px', '');
    var h = doc.height.toString().replace(' px', ''); 
        
    function aspect_ratio(val, lim) {

    var lower = [0, 1];
    var upper = [1, 0];

    while (true) {
        var mediant = [lower[0] + upper[0], lower[1] + upper[1]];

        if (val * mediant[1] > mediant[0]) {
            if (lim < mediant[1]) {
                return upper;
            }
            lower = mediant;
        } else if (val * mediant[1] == mediant[0]) {
            if (lim >= mediant[1]) {
                return mediant;
            }
            if (lower[1] < upper[1]) {
                return lower;
            }
            return upper;
        } else {
            if (lim < mediant[1]) {
                return lower;
            }
            upper = mediant;
        }
    }
}
/////////////////////////////////////////////////////////////////////
app.preferences.rulerUnits = savedRuler;
alert('Document Info' + '\n' + 'Document Name: ' + docName + '\n' + 'Dimensions: ' + w + ' x ' + h + ' pixels' + '\n' + 'Dimensions: '  + Math.round(wMetric * 100) / 100 + ' x ' + Math.round(hMetric * 100) / 100 + ' cm / ' + Math.round(wInches * 1000) / 1000 + ' x ' + Math.round(hInches * 1000) / 1000 + ' inches' + '\n' + 'Resolution: ' + Math.round(ppiRes * 10) / 10 + ' ppi / ' + Math.round(ppcmRes * 1000) / 1000 + ' ppcm' + '\n' + 'Megapixel Value: ' + Math.round(mp * 10) / 10 + ' MP' + ' (' + pix + ' pixels)' + '\n' + 'Aspect Ratio:' + '\n' + ratio.toFixed(2) + ':1' + ' / ' + ratio.toFixed(2) * 2 + ':2 / ' + ratio.toFixed(2) * 4 + ':4' + ' (Basic)' + '\n' + w / r + ':' + h / r + ' (GCD)' + '\n' + aspect_ratio(w / h, 50).toString().replace(',', ':') + ' (Farey)');