Web developers and designers are often plagued with measuring elements either on web pages or their desktops. It isn’t the most fun part of the job, but is often necessary to get the dimensions and balance of things just right. Sometimes, you need to know how much space you have left, or if you can fit another element in the what little room you have. Advanced graphic design apps support rulers and grids that let you do all this easily, but when you want to measure an object outside your favorite app, you have no easy way of doing it. PixelWindow is a free Mac app that gives you an onscreen box for measuring dimensions in pixels. You can set the box to any measurement and move it over different elements to see the difference, or you can fit it over an element to find its width and height.
The app’s interface is a simple box that you can stretch to any length or height by dragging out the corners. The box has a pixel scale drawn along the top and left side, which displays the width and height of the box in the center.
The app can be placed on top of any window, has three preset dimension that you can select, and also support fullscreen mode. To switch the app to fullsceen mode, right-click its interface and select Full Screen On. To change the app to a preset measurement, select Presets and chose either the 800×600, 1024×768 or 1280×800 dimension. To copy the height or width of the box, use the Copy option in the context menu. Double click the app to exit it. PixelWindow can run several instances at once, which means you can have more than one box opened at once to measure several objects.
As far as simple measuring tools go, this one is fairly feature rich and is free. While designers and developers may consider buying better professional and more feature rich apps, this one might still be a good contender.