QGIS Print Layout ID

Question

I want to add layout number to each layout in the print composer. I've cant find a variable with that information in it that I can access from the expression builder.

Generally our projects are built with many single page layouts. They need a unique ID per project, but this ID can overlap with other projects. So I figured we could automate away the task of making sure each layout has a separate ID number printed on it, only I can't figure a way to get at the data within the expression builder.

Does anyone have an idea on a way to get a unique ID onto each print layout? (would prefer an incriminating one like 0,1,2,3,4)

Answer 1

you can make your own expression for that with the function editor:

and then use the new expression in the layout:

with the following code:

from qgis.core import *
from qgis.gui import *

@qgsfunction(args='auto', group='Custom')
def layoutid(layoutname, feature, parent):
    """
    Returns a unique layout id.
    <h2>Example usage:</h2>
    <ul>
      <li>layoutid(@layout_name)
    </ul>    
    """
    manager = QgsProject.instance().layoutManager()
    layoutlist = manager.layouts()
    id = 1
    for layout in layoutlist:
        if layout.name()==layoutname:
            break
        id +=1
    return id