Scale and Tiles Question

Hello. I have a few questions about the scale and tiles.
1.How can I get the current map scale?
2.The tiles on the canvas are stretched and have a size different from the original, so the image is fuzzy. How to make so that the tiles are not stretched?
3.How to scale the levels of tiles?

Can anybody help? Maybe some examples?

To get map scale get 2 rays, each on a different part of the screen. Determine the distance between the terrain points those rays intersect the terrain by using the method described here Now you know how screen distance corresponds to distance along the terrain (well the horizontal component anyways.)

However at high altitude in perspective mode a 2D scale kind of loses its meaning as the Earth curves away from you, it would only be reasonably accurate at lower altitudes. Also pitch would need to be at or near -90.