Toggle view of grid-lines and add-guidelines for Bootstrap 3 pages. Open any page with Bootstrap 3 included and click Photon Redlines to show the grid and add guidelines. + To add guidelines, click and drag horizontally or vertically and you will see the guideline appearing. Release drag to place them comfortable. + To calculate distance values between two guidelines, place the first guideline and drag the second in the same direction. + Once you place the second guideline, its distance (horizontally or vertically, in pixels) will be added. + Double click to clear all guidelines and distance values. + Click Photon Redlines again to hide the grid-lines and guide-lines.