Need Help Measuring on-Screen Objects / Onde Ruler

Hi All - I’m a Forum noobie and this is my first post so please excuse any missteps.

I have recently switched from Windows to MacOS (Big Sur 11.6). For years I used Iconico Calipers in Windows to measure objects on the screen. Unfortunately, Calipers is not available for Mac.

I want to be able to measure the size/length of objects on the computer screen.

I have purchased Onde Rulers and am sure it will do what I need it to. But, I cannot figure out how to calibrate the ruler’s units. I need to set the ruler so that it, for example, knows that a 400 pixel long object on the screen is 8" long in the real world. Then when I move the ruler and measure an object half that size (200 px) the ruler will read 4".

When I try to calibrate units on the Onde Rulers I am not able to make a ratio between pixels and inches stick. If I input a number of pixels and then a number of inches, the number of pixels updates. If I try to do it the other way around, setting the inches first, that number changes when I enter a new pixels count.

I would love too hear from someone who is familiar with Onde Rulers and could explain the correct step-by-step order of calibrating units.

Failing that, anyone who uses screen measuring software that they love will PLEASE jump in an and make a recommendation.

Thank you!! Jim in Maine, USA

The only measurement tools I use are CADTools within Illustrator.

How are you using these screen calipers? Or for what purpose? As a stand alone app, or a plug-in within some other software?

Hi PrintDriver – I need a standalone app. As an example of my intended use: Say I am viewing a photo of an open refrigerator …maybe in PhotoShop or Affinity Designer or maybe even a web browser.

I open the ruler app and it automatically determines the active pixel/screen resilution so that when I position the ruler to measure the height of the refrigerator’s image it shows, for example, 620 pixels.

I then calibrate the ruler’s units; I know the fridge is 70" tall so I set 620 pixels as equalling 70 inches.

I am then able to move the ruler so it’s measuring the distance between two shelves inside the refrigerator …the ruler displays the distance as 10.25". I can turn the ruler to horizontal and measure the width of the fridge to be 36 inches.

If at any point I change the screen’s resolution, switch to a closeup image, etc. I will have to re-calibrate the ruler before making subsequent measurements.

I hope the above makes some sense. Thank you for your interest!!

My curiosity is piqued — what type of projects are you working on that require this? Also, I’d be leary of how accurate this type of thing is. With perspective issues and lens distortion, I wouldn’t count on this type of measurement for anything critical.

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Hi Steve:

Sorry this reply is delayed. I had attempted to reply to the email notice I had received from GDF, but that appears to not arrived her the way I’d anticipated.

I’m pretty much retired. I was trained as a photographer so even when I was most active I was a self-taught, amateur graphic designer. I manage a couple of small “non profit” websites so nothing is highly critical and I’m not working to satisfy a boss or critical client. :wink:

A lot of the measuring I do would be on the screen image of a photograph or illustration. My refrigerator example came from real life last week. My wifehood ordered a new fridge online. While waiting fior it to be delivered she was wondering about the shelf and drawer spacing. The only thing shown in the manual pdf page was a line drawn illustration. I knew the overall height and width. Yes, I could print the drawing, measure the image on paper and calculate a scale, e.g 1” on paper = 14.5 real world inches. But, much easier to slide an onscreen ruler around and grab “real time” measurements without use of a calculator.

I would sometimes use the calipers while working in programs like Affinity Photo or Publisher — very often I would mostly be interested in the relative sizes of objects in the layout. In those cases I could just use the raw measurements in pixels.