78 lines
2.2 KiB
Python
78 lines
2.2 KiB
Python
import abc
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class DrawEngine(abc.ABC):
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"""
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This is an abstract class that defines the methods needed
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to have a drawing backend.
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This interface was *extracted* not designed.
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The first version of this library had a hard dependency on pygame
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for drawing. Each shape had an overriden draw method that called
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pygame functions directly.
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The refactor in https://github.com/jamesturk/doodles/pull/1
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pulled this out by searching the code for all pygame references
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and extracting them into their own class. `PygameDrawEngine`.
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These are the signatures of that classes methods, so that
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a new implementation (to draw in OpenGL, or the browser, or on PDFs)
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could provide the necessary implementations of these functions.
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Note that starting with these as embedded and then extracting them
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is a perfectly valid way to get here, you could also be diligent
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while writing in the first place, and ensure that code needing
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isolation (such as a library you want to avoid tight coupling to)
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only is added to a specific class or module.
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TODO: this got behind the current impl
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"""
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@abc.abstractmethod
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def init(self):
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"""
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Called once, provides a place for the backend to initialize
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itself as needed.
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"""
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@abc.abstractmethod
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def render(self, background_color: "Color", drawables: list["Doodle"]):
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"""
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Workhorse function, should set background and then draw all Doodles.
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Will be called once per frame.
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"""
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@abc.abstractmethod
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def circle_draw(self, circle: "Circle"):
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"""
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Method to draw a Circle obj.
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"""
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@abc.abstractmethod
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def rect_draw(self, rect: "Rect"):
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"""
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Method to draw a Rectangle obj.
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"""
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@abc.abstractmethod
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def line_draw(self, line: "Line"):
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"""
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Method to draw a Line obj.
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"""
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@abc.abstractmethod
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def text_render(self, text: "Text"):
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"""
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Method to pre-render a text object.
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"""
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@abc.abstractmethod
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def text_draw(self, text: "Text"):
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"""
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Method to draw a pre-rendered text object.
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"""
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# TODO: should make_font/get_font become part of the
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# reqwuired interface?
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