Feature: Expand all towns in the scenario editor

[perezdidac]

Motivation / Problem

• As a user, I want to make all towns grow in the scenario editor in case I want to play a game with towns and cities that have more population.
• I asked around on Discord and people seemed excited about adding this functionality.

Description

This code change adds a button in the town window in the scenario editor that will expand all towns on the map.

Limitations

This code change does not add a button to decrease the population of all downs.

Checklist for review

N/A

[LC-Zorg]

It's funny, but not so long ago, that's exactly what I missed. :) I was working on a scenario where many cities were very small, literally 2-4 buildings, which often made it difficult for them to start growing at all. So I think this could be a useful feature. :)

If I had to make a comment, it would be that small cities grow too much, and big ones too little, often hardly at all. In the case of the expansion function that is in the city window, each press will enlarge the city by about 20%. Is it possible (easy to do) to make the multi-city extension work similarly?

I also think it might be worth adding a confirmation request for at least "Many random towns" - this feature is beside and accidentally pressing it when expanding towns can cause unpleasant results.

[2TallTyler]

If you can get these changes done promptly, this would be good to have in OpenTTD 13 (Release Candidate build and feature-freeze coming soon ™️). 😃

[perezdidac]

It's funny, but not so long ago, that's exactly what I missed. :) I was working on a scenario where many cities were very small, literally 2-4 buildings, which often made it difficult for them to start growing at all. So I think this could be a useful feature. :)

If I had to make a comment, it would be that small cities grow too much, and big ones too little, often hardly at all. In the case of the expansion function that is in the city window, each press will enlarge the city by about 20%. Is it possible (easy to do) to make the multi-city extension work similarly?

I also think it might be worth adding a confirmation request for at least "Many random towns" - this feature is beside and accidentally pressing it when expanding towns can cause unpleasant results.

I made the changes that @2TallTyler suggested and now it effectively does what you suggest :D

[perezdidac]

Thank you guys!