Question

This question is related to this other one.

In my program (which uses pygame to draw objects on the video) I have two representation of my world:

• A physical one that I use to make all the calculations involved in the simulation and in which objects are located on a 1000×1000 metres surface.
• A visual one which I use to draw on the screen, in which my objects are located in a window measuring 100×100 pixels.

What I want to achieve is to be able to pass to my pygame drawing functions (which normally accept inputs in pixels) my physical/real-word coordinates. In other words, I would like to be able to say:

Draw a 20m radius circle at coordinates (200m, 500m)

using the precise pygame syntax:

pygame.draw.circle(surface, (255,255,255), (200,500), 20)

and get my circle of 2px radius at centred on pixels (20,50).

Please note that this question is about a native pygame way to do this, not some sort of workaround to achieve that result (if you want to answer that, you should take a look to the question I already mentioned) instead.

Thanks in advance for your time and support.

Answer 1

Since it seems that PyGame developers do not hang around here too much, I brought the question to the Pygame mailing list where it originated a monster thread and the issue has been debated at large.

The summary would be:

• At present there is not such a feature.
• There is interest to implement it, or at least to try to implement it…
• …although is not a priority of the core devs in any way
• There is more than one way to skin a cat:
  • should be the scaling happen both ways (inputting coordinates and reading them)?
  • how to deal with lines that have no thickness but that should be visible?
  • how to deal with visibility of objects at the edge of the image? which of their points should be taken as reference to know if a pixel should be lit or not for them?
  • and more (see linked thread).