linebender/druid

Decouple piet and druid-shell

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#1924 opened on Aug 16, 2021

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 (8 comments) (1 reaction) (0 assignees)Rust (9,091 stars) (567 forks)batch import
architecturehelp wanted

Description

It is not currently possible to use druid-shell without using piet, and I think this is an unnecessary coupling, and it makes druid-shell strictly less useful.

I would like to move all of the piet-specific code from druid-shell into druid. In practice this means:

  • Any shared PietText objects should live somewhere in druid (unclear where, exactly, druid doesn't really have an application-global object? maybe the AppHandler?)
  • instead of passing a RenderContext to the paint method, druid-shell should pass a window handle
  • druid should construct the RenderContext itself, from the window handle

This does violate the principal that platform-specific code should generally be in druid-shell instead of druid. Is there a viable alternative? I'm not sure if there's a good one, although we could perhaps have a from_raw_handle(handle: &RawWindowHandle) -> RenderContext method in piet-common? I'm not sure if this really makes a ton of sense, but it's an option?

If someone is interested in taking this on, I am happy to answer questions.

Contributor guide

Tech stack
rust
Domain
desktop
Issue type
refactor
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Rustdruidpietplatform abstraction
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
Investigate where PietText objects are currently used in druid shell and how they are shared. Look into modifying the paint method to pass a window handle instead of a RenderContext, and then constructing the RenderContext in druid from that handle. Consider the alternative of adding a from raw handle method to piet common. Review issue comments for any additional design considerations.