Add 2D Graphics library #39
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| instance : Inhabited Picture where | ||
| default := .blank | ||
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| instance : Append Picture where |
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@paulcadman Picture is probably also a Monoid
Given how Image is described by Conal in
Denotational Design: From Meanings To Programs • Conal Elliott • YOW! 2015
https://www.youtube.com/watch?v=rlyqoYoUumc
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@awalterschulze you're right, but I couldn't find a separate Monoid class in Lean4 prelude.
The Append class is equivalent to Haskell Semigroup. And Inhabited + Append is equivalent to Haskell Monoid.
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And thanks for the YouTube link - I had forgotten that Image was the example in Conal's talk. Perhaps we should use his encoding instead.
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Ah ok, I didn't know Lean was missing a Monoid class, TIL about Append + Inhabited = Monoid. I think this clears some things up about Inhabited for me, hmmm :O
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I'll have to rewatch the Conal talk again to remember anything tangible besides the monoid part. The rest was more a way a thinking about code, which has been really useful.
We don't have to fully go down this path though. I think what you have setup is already really cool.
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I think he did something else where he didn't evaluate the transformations until he new the size of the picture he needed to draw, so that way he never loses any picture quality from scaling up and down
The goal of this PR is to provide a 2D Graphics library layer on top of raylib's API that's more uniform with respect to coordinates in a window and provides scaling and translation transformations on rectangles and circles and aggregations thereof.
The coordinate system for objects in the 2D Graphics library has its origin in the centre of the window instead of the top-left of the screen. And the y-axis values increase with increasing height.
See the Window and Orbital demos for examples of usage.
This PR also adds the
cfoldandcollectECS system functions that can be used to fold over / collect matching components respectively. Thecollectfunction is used in the Orbital demo.