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I have a 27" iMac running Snow Leopard. In a wide range of applications I often need to use a straight edge to compare different values on charts, even sometimes charts generated by different applications. To do this I have made do with clumsy solutions like creating a floating and transparent Sticky or using Shift + Command + 4. I've also tried a small app called Crosshairs.

None of these things do what I really want. Ideally, I'd like a full screen crosshair centered on the cursor. Another way to think about this, it would give me a full height vertical and full width horizontal line that would show up over (on top of) any and all applications, just as a cursor does. Nice to haves it would give the coordinates of the display and have toolbar or right click access to turn it on or off.

Any suggestions?

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SnagIt for Mac does exactly this: a full screen crosshair with pixel coordinates, when you take a screen shot. But it's only designed for screen shots. – user9290 Apr 13 '12 at 14:57
up vote 4 down vote accepted

While it has many more features than this, something like xScope sounds great for this.

Some main features:

  • mirroring
  • getting on screen dimensions
  • rulers
  • guides
  • frames
  • crosshair
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Great little app. WAy more than I need for what I do need of it works like a charm. Thanks. – Jagra Apr 13 '12 at 22:01

Free solution: Mouse Locator

You can make whatever custom cursors you want.

Hotkeys can turn it on/off, and if you want coordinates, you could launch Pixie (or another app) and keep it in the corner.

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For a different approach, you can try Free Ruler for Mac OS X. This free application displays a horizontal and a vertical ruler, both of which you can extend. It supports different scales (cm, mm, pixels, inches, etc - it's using the screen DPI to display distance measurements correctly).

I use it quite often when I need pixel-perfect measurements of GUI elements, or other stuff and the application I work with doesn't give me what I need in terms of the measurements.

Please note, I'm NOT affiliated with the developer in any way, just a happy user for the occasional time that an application like this serves my needs.

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Thanks for the recommendation. xScope still does everything I need it to do. – Jagra Nov 12 '14 at 21:04

There's a new app on the App Store called Euclid that claims to do what you're asking. I have not personally tried it but it looks nice enough!

edit: I went ahead and bought Euclid to try it out. Nice little app and the crosshairs do work well. My only gripe at this point is that I wanted to take screenshots with it and as of now it doesn't do that nor does it work with the built in Cmd-Shift-4 tool. I've emailed the developer and am hoping he responds with an update.

update1: The Euclid dev has responded to me stating that he's working on imrpovements. Hopefully these will be forthcoming!

update2: I found another possible solution, there's a free app called Monosnap that displays full-screen crosshairs when capturing an area. You can trigger it via a hotkey and then hit ESC to cancel without actually taking a screenshot if all you want to do is use the crosshairs for alignment.

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