Just include it in your project, and you can overlay a debug grid with the g Key.

Protips:

• press Shift - g to toggle between 6 and 12 columns.
• press l to display lines as well
• press Shift - l to toggle the visibility of columns only

Add this to your pubspec.yaml:

dependencies:
  debug_grid: any

In your html, just include the grid like this:

<link rel="import" href="packages/debug_grid/debug_grid.html">

and put this at the end of your body tag:

<debug-grid></debug-grid>

That's it, you're good to go!

I'm assuming you have already a project setup with polymer! If not, please refer to the polymer dart documentation on how to do that, because this grid will not work otherwise.

Here is a fully configured debug grid:

<debug-grid totalWidth="1128"
            gutterWidth="24"
            lineHeight="24"
            columns="3"
            showColumns="false"
            showLines="true"
            visible="true"
            toggleKey="83"
            linesToggleKey="86"></debug-grid>

This would display a 1128px wide grid with 24px wide gutters, 24px line height and 3 columns. By default it is visible and would not show columns, but only lines (which can be toggled with the appropriate keys).

The visibility toggle key has been remapped to 83 (s) and the lines toggle key has been remapped to 86 (v).

MIT License