Directly setting the crop size in pixels

[ShaunTheDuke]

I know that it is possible to set a specific pixel size and resolution when using the crop tool. The crop border will then be constrained to the aspect ratio of your chosen dimensions as you drag and move etc. Then when you commit the crop it will resize the image to the specific pixel dimensions you have given.

But, that is not what I want to do. Importantly, setting the dimensions does nothing to the crop border. If I have a 1000x1000 px image and specify a 100x100 px crop, the border remains at 1000x1000 px and I have to drag the handles to 100x100 px if I want to crop to a specific 100x100 px region. This is an absurd pain the backside when working with a trackpad, trying to hit the exact size takes way too long.

I want to be able to set a specific size in pixels and for the crop border to assume that size. Then I can drag the crop around and get those exact pixel dimensions from the region I want. 

I was a long time user of PaintShop Pro prior to Photoshop. In PSP you could just enter the pixel dimensions and the crop border snapped to that exact size.

Am I missing something simple here?

Thanks in advance.

[Mohammad.Harb]

If I understand your question, you can consider using 

image -> canvas size, 

[ShaunTheDuke]

Hi Mohammad,

Canvas size doesn't provide the necessary level of control.

Yes, you can of course set the specific pixel dimensions, but you cannot choose which portion of the image you want to retain, other than centre, top left etc anchoring.

Think of it like this. Let us say I have an array or grid of icons in a 1000x1000 pixel image each icon is 100x100 pixels so 10 rows of 10 icons.  Let us now imagine that I need to crop to just a single icon. Sure I can set the height and width of the crop but the border doesn't change and I have to spend valuable time fighting the trackpad or graphics tablet going backwards and forwards between 98x98 and 101x101 pixels before I get lucky and hit 100x100.

I hope it's obvious that getting close and resizing is not an option as I'll get the edge of the adjacent icon in my resized image. If I could just enter the dimensions and get the border to snap to that exact size it would be so much faster.

I know also, that in my example above, I could zoom in close on the icon in question and it would be an easy task to acomplish. But today I needed to take exactly 3000 specific pixels out of a 6000x4000 image. Yes, I could zoom but it's extra time on a workaround.

Cheers Shaun

[Stephen Marsh]

I think that you'll need to use the Rectangular Marquee Selection tool [m] and draw out your crop area, then use the Image > Crop command. I appreciate that part of the issue is easily drawing a crop or marquee to the desired pixel sizes when using a trackpad.

[ShaunTheDuke]

Hi Stephen,

Thanks and yes it is all about that issue of getting the exact size. It is possible with zooming in to increase the precision with which you can drag out a crop or selection but it is a faffy workaround.

I was hoping for a simple, yeah just hold shift or whatever when you enter the crop dimmensions.

Cheers, Shaun

[Stephen Marsh · Accepted solution]

The following script will create a rectangular selection at the width and height entered into the prompts. By default, it is drawn at the upper left (0x 0y).

You can then position the marquee where you wish to crop, then use Image > Crop.

At least you will get your desired size, I hope that this helps!

// Create Rectangular Selection from Prompts.jsx

#target photoshop

    (function () {

        /* Width Input */
        // Loop the input prompt until a number is entered
        var origWidth;
        while (isNaN(origWidth = prompt("Selection width in pixels:", "100")));
        // Test if cancel returns null, then terminate the script
        if (origWidth === null) {
            alert('Script cancelled!');
            return
        }
        // Test if an empty string is returned, then terminate the script 
        if (origWidth === "") {
            alert('A value was not entered, script cancelled!');
            return
        }
        // Convert decimal input to integer
        var widthToInteger = parseInt(origWidth);

        /* Height Input */
        // Loop the input prompt until a number is entered
        var origHeight;
        while (isNaN(origHeight = prompt("Selection height in pixels:", "100")));
        // Test if cancel returns null, then terminate the script
        if (origHeight === null) {
            alert('Script cancelled!');
            return
        }
        // Test if an empty string is returned, then terminate the script 
        if (origHeight === "") {
            alert('A value was not entered, script cancelled!');
            return
        }
        // Convert decimal input to integer
        var heightToInteger = parseInt(origHeight);

        /* Call the Rectangular Selection Function */
        setRectSel(0, 0, heightToInteger, widthToInteger);

        /* Set Rectangular Selection Function */
        function setRectSel(top, left, bottom, right) {
            var c2t = function (s) {
                return app.charIDToTypeID(s);
            };
            var s2t = function (s) {
                return app.stringIDToTypeID(s);
            };
            var descriptor = new ActionDescriptor();
            var descriptor2 = new ActionDescriptor();
            var reference = new ActionReference();
            reference.putProperty(s2t("channel"), s2t("selection"));
            descriptor.putReference(c2t("null"), reference);
            descriptor2.putUnitDouble(s2t("top"), s2t("pixelsUnit"), top);
            descriptor2.putUnitDouble(s2t("left"), s2t("pixelsUnit"), left);
            descriptor2.putUnitDouble(s2t("bottom"), s2t("pixelsUnit"), bottom);
            descriptor2.putUnitDouble(s2t("right"), s2t("pixelsUnit"), right);
            descriptor.putObject(s2t("to"), s2t("rectangle"), descriptor2);
            executeAction(s2t("set"), descriptor, DialogModes.NO);
        }

        /* Select the Rectangular Marquee Selection tool */
        (r = new ActionReference()).putClass(stringIDToTypeID('marqueeRectTool'));
        (d = new ActionDescriptor()).putReference(stringIDToTypeID('target'), r);
        executeAction(stringIDToTypeID('select'), d, DialogModes.NO)

    })
    ();

https://prepression.blogspot.com/2017/11/downloading-and-installing-adobe-scripts.html

[ShaunTheDuke]

That is neat, I like, thank you. 

As you will see I'm rather new here. I want to give you credit, but I'm not sure whether to mark as the correct answer. It is a workable solution, just not what I'd expected. What do you think ?

Cheers, Shaun

[Stephen Marsh]

There can be multiple correct answers, so if a better one comes along you can mark that as correct as well.

[davescm]

An alternative way

1. Drag out a rectangle with the rectangular marquee tool (size doesn't matter)

2. Select > Transform Selection and type in the size you want in the options bar e.g 100 x 100 px into W and H

3. Drag the rectangle to where you want it

4. Image > Crop

Dave

[Stephen Marsh]

That works too Dave and was my first thought, however, when I recorded it into an action the resize is recorded in a % and not as a fixed px value.  The end result should be the same though.

EDIT: It is possible to create an action that does use an explicit pixel size...