examples/fidl/new/canvas/baseline/fidl/canvas.test.fidl

// Copyright 2022 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
library examples.canvas.baseline;

/// A point in 2D space.
type Point = struct {
    x int64;
    y int64;
};

/// A line in 2D space.
alias Line = array<Point, 2>;

/// A bounding box in 2D space. This is the result of "drawing" operations on our canvas, and what
/// the server reports back to the client. These bounds are sufficient to contain all of the
/// lines (inclusive) on a canvas at a given time.
type BoundingBox = struct {
    top_left Point;
    bottom_right Point;
};

/// Manages a single instance of a canvas. Each session of this protocol is responsible for a new
/// canvas.
@discoverable
open protocol Instance {
    /// Add a line to the canvas.
    flexible AddLine(struct {
        line Line;
    });

    /// Update the client with the latest drawing state. The server makes no guarantees about how
    /// often this event occurs - it could occur multiple times per board state, for example.
    flexible -> OnDrawn(BoundingBox);
};