Is possible to write a script that can AUTO CROP image to best fit aspect ratio ?

[Calvin21914323wi10]

I have images that with differnt dimentions, mix with protrait and lanscape, is there any script can detect the image size then auto crop to best fit aspect raio : 1:1, 2:3, 3:4, 4:5, 5:7, 2:1, 3:1 / 3:2, 4:3, 5:4, 7:5, 1:2, 1:)

I tried ask chatGPT to help (LOL), it gave me some messy and cofused code.

Then I did a lot searches, no resources can provide some hints to start to code it.

Any ideas ? Thanks

[c.pfaffenbichler]

I don’t think I fully understand the process. 

Could you post screenshots for an example (what do you start with, what is the intended final result, …)? 

[Calvin21914323wi10]

Thank you, I uploaded 4 files (mixed with protrait and lanscape)

File 1 : 2374*1795, best fit with 4:3 aspect ratio crop

File 2 : 5768*4620, best fit with 5:4 aspect ratio crop

File 3 : 1290*1722, best fit with 3:4 aspect ratio crop

File 4 : 1001*1928, best fit with 1:2 aspect ratio crop

I have over 50 such files with different dimensions in a single folder; I want a script that can auto-detect their sizes and determine to crop them with varying best-fit ratios of aspect, then save them to different folders named 43, 54, 34, 12 and so on........

The images could be in 1:1, 2:3, 3:4, 4:5, 5:7, 2:1, 3:1, 3:2, 4:3, 5:4, 7:5 ratios. Even if I manually crop them, I still need to find out the best-fit aspect ratio many times, so I want automatic this to work.

This script is beyond my ability; any ideas to make it?

[c.pfaffenbichler]

Why do you list 2:3 and 3:2 and 4:5 and 5:4 etc. separately? 

Does this mean that 2:1 and 3:1 are only applicable to landscape and MUST NOT be applied to portrait? 

[Calvin21914323wi10]

Yes, strictly follow the original art image.

[Bojan Živković]

Once upon a time I was creating program in Python to do similar thing, to determine best available solution. I do not know how to using Javascript. Maybe you can find something already writen in JavaScript for similar purpose and to use it for manual work, at least. 

[r-bin]

File 1 : 2374*1795, best fit with 4:3 aspect ratio crop

File 2 : 5768*4620, best fit with 5:4 aspect ratio crop

File 3 : 1290*1722, best fit with 3:4 aspect ratio crop

File 4 : 1001*1928, best fit with 1:2 aspect ratio crop

By @Calvin21914323wi10

Didn't check everything, but it works on your data.

alert("2374*1795 " + get_optimal_crop(2374, 1795));
alert("5768*4620 " + get_optimal_crop(5768, 4620));
alert("1290*1722 " + get_optimal_crop(1290, 1722));
alert("1001*1928 " + get_optimal_crop(1001, 1928));

function get_optimal_crop(w,h)
    {
    try {
        var crops = [[1,1], [1,2], [1,3], [2,3], [3,4], [4,5], [5,7]];

        var a0 = 0;
        var i0 = 0;

        for (var i = 0;  i < crops.length; i++)
            {
            var a = get_area();
        
            if (a0 < a) { a0 = a; i0 = i; }

            function get_area()
                {
                try {
                    var w1, h1;
    
                    if (w > h && crops[i][0] < crops[i][1])
                        {
                        var tmp = crops[i][0];
                        crops[i][0] = crops[i][1];
                        crops[i][1] = tmp;
                        }
    
                    var w0 = crops[i][0];                    
                    var h0 = crops[i][1];                    
            
                    if (w/h < w0/h0)
                        {
                        w1 = w;
                        h1 = Math.round(w*h0/w0);
                        }
                    else
                        {            
                        h1 = h;
                        w1 = Math.round(h*w0/h0);
                        }    
    
                    return w1*h1;
                    } 
                catch(e) { throw(e); }
                }
            }

        return crops[i0];
        }
    catch(e) { throw(e); }
    }

[Calvin21914323wi10]

Tested, I don't know why just no respose at all

[c.pfaffenbichler]

Tested, I don't know why just no respose at all

By @Calvin21914323wi10

Wikipedia states 

»Repose is a word meaning "rest" or "calmness".«

so there might be a typo. 

[Calvin21914323wi10]

Response, I mean. I ran it but nothing happened at all

[Signfeld]

Have you studied, understood, and tried the File > Automate > Fit Image... script and is it not what you want...?

If it only works for some photos, you could indeed write a script that uses a different Fit Image... depending on sizes or ratios the script detects — or just do them in separate batches.

PS: Fit Image will use the Image Interpolation set in Preferences.

[Signfeld]

BTW, you can also use Conditional steps, so you don't necessarily need your own script.

 

[Stephen_A_Marsh]

There are different algorithms to determine aspect ratios, the following code uses 3 different ones:

/*
Photoshop Document Dimensions - MP Value - Aspect Ratio.jsx
v1.0, Stephen Marsh 13th February 2022
*/

#target photoshop

var savedRuler = app.preferences.rulerUnits;
app.preferences.rulerUnits = Units.PIXELS;

var w = app.activeDocument.width.value;
var h = app.activeDocument.height.value;
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.value;
var h = doc.height.value;

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)'
);

app.preferences.rulerUnits = savedRuler;


function gcd(a, b) {
    /* https://stackoverflow.com/questions/1186414/whats-the-algorithm-to-calculate-aspect-ratio-i-need-an-output-like-43-169 */
    return (b == 0) ? a : gcd(b, a % b);
}

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;
        }
    }
}

Adobe Bridge has a filter for aspect ratio, which you can use to open all files in a folder with the same ratio... But you would have to determine the threshold and fuzziness as to what matches what.

[Calvin21914323wi10]

Thank you very much, will test in my images.

[Stephen_A_Marsh]

For your "1_43.jpg" sample, Bridge lists the aspect ratio as 3:4, however you would class this as 4:3 as it is landscape.

My script reports the following for the same image:

Aspect Ratio:

1.32:1 / 2.64:2 / 5.28:4 (Basic)

2374:1795 (GCD)

41:31 (Farey)

So the Farey formula is closest to Bridge in this case with rounding, but the GCD formula is better from memory in other cases.

I don't know if there is a single "best" formula. Math isn't my strong point, I had to adapt various JS codes for Photoshop.

[Calvin21914323wi10]

Tested, it can detect and show information but not crop the image

[c.pfaffenbichler]

Tested, it can detect and show information but not crop the image

By @Calvin21914323wi10

One can crop both via DOM- and AM-code so what is giving you problems? 

[Calvin21914323wi10]

Yes, I tried run in action, no crop, then I added my own crop function, still not work, maybe I am too stupid to code

[Stephen_A_Marsh]

Tested, it can detect and show information but not crop the image

By @Calvin21914323wi10

That is correct, the solution isn't handed to you on a silver platter!

Before one can even think about cropping, a suitable aspect ratio detection method has to be found, and then you have to determine some sort of pass/fail threshold tolerance etc.

[Calvin21914323wi10]

Thank you, but even the best one - Farey, still not give out a exact ratio e.g.File 4 - best fit is 1:2, but it gave 13:25 very accurate but not a POPULAR RATIO (SELLERABLE PRINT SIZE RATIO), I hope you understand what I want to say.

Now I am trying use excel find my algorithm, but found many weird ratio in my collection, scratching my head and try to do more market research

[Stephen_A_Marsh]

Indeed, these are the challenges.

Have you looked at the Adobe Bridge aspect ratio filter?

[c.pfaffenbichler]

Does this provide meaningful results? 

// determine closest ratio from a limited set;
// 2023, use at your own risk;
if (app.documents.length > 0) {
    app.togglePalettes();
    var originalRulerUnits = app.preferences.rulerUnits;
    app.preferences.rulerUnits = Units.PIXELS;
    var myDocument = activeDocument;
    var theW = myDocument.width;
    var theH = myDocument.height;
    var theProportion = theW/theH;
    var theProportions = [[2,3], [5,7], [3,4], [4,5], [1,1], [5,4], [4,3], [7,5], [3,2], [2,1], [3,1]];
    var theResult = theProportions.sort(sortArrayByDifference)[0];
    var thisProp = theResult[0]/theResult[1];
    if (theProportion < thisProp) {
        var targetW = theW;
        var targetH = theW*theResult[1]/theResult[0];
    }
    else {
        var targetW = theH*theResult[0]/theResult[1];
        var targetH = theH;
    };
    alert ("at the aspect ratio "+theResult.join("/")+" the image would be\n"+targetW+" x "+targetH);
    app.preferences.rulerUnits = originalRulerUnits;
    app.togglePalettes();
};
////// sort by difference to a number //////
function sortArrayByDifference(a,b) {
    if (Math.abs((a[0]/a[1])-theProportion)<Math.abs((b[0]/b[1])-theProportion)) return -1;
    if (Math.abs((a[0]/a[1])-theProportion)>Math.abs((b[0]/b[1])-theProportion)) return 1;
    return 0;
    };

[Calvin21914323wi10]

Thank you very much, it works

I added

app.activeDocument.crop.........

and it works, thanks again

[Stephen_A_Marsh]

Thank you very much, it works

I added

app.activeDocument.crop.........

and it works, thanks again

By @Calvin21914323wi10

Please share the final code, I for one would be interested.

EDIT:

https://theiviaxx.github.io/photoshop-docs/Photoshop/Document/crop.html

[Calvin21914323wi10]

Thanks to @c.pfaffenbichler , I added 2 lines only

if (app.documents.length > 0) {
    app.togglePalettes();
    var originalRulerUnits = app.preferences.rulerUnits;
    app.preferences.rulerUnits = Units.PIXELS;
    var myDocument = activeDocument;
    var theW = myDocument.width;
    var theH = myDocument.height;
    var theProportion = theW/theH;
    var theProportions = [[1,3],[1,2],[2,3], [5,7], [3,4], [4,5], [1,1], [5,4], [4,3], [7,5], [3,2], [2,1], [3,1]];
    var theResult = theProportions.sort(sortArrayByDifference)[0];
    var thisProp = theResult[0]/theResult[1];
	
    if (theProportion < thisProp) {
        var targetW = theW;
        var targetH = theW*theResult[1]/theResult[0];
    }
    else {
        var targetW = theH*theResult[0]/theResult[1];
        var targetH = theH;
    };
	var bounds = [0,0,targetW, targetH]
    alert ("at the aspect ratio "+theResult.join("/")+" the image would be\n"+targetW+" x "+targetH);
	app.activeDocument.crop(bounds);
    app.preferences.rulerUnits = originalRulerUnits;
    app.togglePalettes();
	
    
};
////// sort by difference to a number //////
function sortArrayByDifference(a,b) {
    if (Math.abs((a[0]/a[1])-theProportion)<Math.abs((b[0]/b[1])-theProportion)) return -1;
    if (Math.abs((a[0]/a[1])-theProportion)>Math.abs((b[0]/b[1])-theProportion)) return 1;
    return 0;
    };