How to make canvas for retina on ios?

Question

Canvas

Mobile browsers double the size
. That is, if my Canvas is 100x100, then it will be displayed as 200x200 with interpolation?
How to make Canvas display pixel-for-pixel?
What did Vadim Makeev from Opera Software mean in the presentation "Clearly and sharply"??
in the second paragraph:
set the size twice?

Answer 1

https://www.google.ru/webhp?sourceid=chrome-instan...