Is it possible in QGIS print composer to include a numeric scale in an html box?

Question

For work I always have to create a table with my name, project name, date etc. into my map layouts. I also need to include the scale like "1:150000" in that table.

So far I am solving that by including an html table with the html box function of the print composer. Is there a way to automatically include the right scale? So far I only managed to automatically include the date by using a little javascript. Maybe something similar is also possible for the scale?

Answer 1

Tested with QGIS 3.6.1

As mentioned in the documentation, you can create a label and insert this code to get the current scale for the map with the item name Map 0:

map_get( item_variables('Map 0'), 'map_scale')

Answer 2

You can register expression function to get your map scale. For example:

from qgis.utils import iface 

@qgsfunction(args='auto', group='Custom')
def get_composer_map_scale(comp_window_title, feature, parent):
    composer_views = iface.activeComposers()
    my_composition = None
    for view in composer_views:
        if view.window().windowTitle() == comp_window_title:
            my_composition = view.composition()
            break
    if my_composition is not None:
        # adjust map id below if you have more maps in the composer
        comp_map = my_composition.getComposerMapById(0)
        scale = '{:.0f}'.format(round(comp_map.scale(), 0))
        return scale
    else:
        return 'Unknown'

And use it in your HTML box or label:

Scale 1:[%get_composer_map_scale( 'Composer 1' )%]

where 'Composer 1' is your composer title.