This is awesome! Such a wonderfully simple idea, and pretty nice execution to boot. I normally rely heavily on Cmd-Shift-4 on OS X for measuring stuff on screen (click, drag, then Esc to cancel before actually taking a screenshot), but I have a feeling this extension will be a pretty significant improvement over my approach. Great work!
For those that don't see a use case: Chrome's dev tools work well for measuring things within the context of the box model, but so much of what I measure on a regular basis isn't captured there. The best example I can think of is measurements relative to some text's baseline—the distance between the bottom baseline of some text and the border of its parent container, including adjustments for line height, padding, and related margins, for instance. This extension would also work for things that aren't even represented in the box model, like the distance between two shapes in a <canvas> element.
One feature suggestion: it'd be great to be able to click or use another keyboard shortcut to set arbitrary anchor points on the page. That way, I could measure the distance between elements that aren't necessarily on the same vertical or horizontal axis. That's one thing that OS X's screenshot utility is great for (though perhaps unintentionally).
For everyone who uses Cmd-Shift-4, try Cmd-Cntrl-Shift-4 to accomplish the same thing without risking a 31px by 2px file cluttering your desktop when you don't click Esc on time.
Very true and I can't imagine using any device without a multi-clipboard manager. I'm pretty surprised Windows, OS X, Android, iOS, etc. don't already have them built-in by now or at least optional within the system preferences somewhere.
For those that don't see a use case: Chrome's dev tools work well for measuring things within the context of the box model, but so much of what I measure on a regular basis isn't captured there. The best example I can think of is measurements relative to some text's baseline—the distance between the bottom baseline of some text and the border of its parent container, including adjustments for line height, padding, and related margins, for instance. This extension would also work for things that aren't even represented in the box model, like the distance between two shapes in a <canvas> element.
One feature suggestion: it'd be great to be able to click or use another keyboard shortcut to set arbitrary anchor points on the page. That way, I could measure the distance between elements that aren't necessarily on the same vertical or horizontal axis. That's one thing that OS X's screenshot utility is great for (though perhaps unintentionally).