1use super::Element;
 2use crate::{
 3    json::{self, json},
 4    presenter::MeasurementContext,
 5    DebugContext, PaintContext,
 6};
 7use json::ToJson;
 8use pathfinder_geometry::{
 9    rect::RectF,
10    vector::{vec2f, Vector2F},
11};
12
13pub struct Canvas<F>(F);
14
15impl<F> Canvas<F>
16where
17    F: FnMut(RectF, RectF, &mut PaintContext),
18{
19    pub fn new(f: F) -> Self {
20        Self(f)
21    }
22}
23
24impl<F> Element for Canvas<F>
25where
26    F: FnMut(RectF, RectF, &mut PaintContext),
27{
28    type LayoutState = ();
29    type PaintState = ();
30
31    fn layout(
32        &mut self,
33        constraint: crate::SizeConstraint,
34        _: &mut crate::LayoutContext,
35    ) -> (Vector2F, Self::LayoutState) {
36        let x = if constraint.max.x().is_finite() {
37            constraint.max.x()
38        } else {
39            constraint.min.x()
40        };
41        let y = if constraint.max.y().is_finite() {
42            constraint.max.y()
43        } else {
44            constraint.min.y()
45        };
46        (vec2f(x, y), ())
47    }
48
49    fn paint(
50        &mut self,
51        bounds: RectF,
52        visible_bounds: RectF,
53        _: &mut Self::LayoutState,
54        cx: &mut PaintContext,
55    ) -> Self::PaintState {
56        self.0(bounds, visible_bounds, cx)
57    }
58
59    fn rect_for_text_range(
60        &self,
61        _: std::ops::Range<usize>,
62        _: RectF,
63        _: RectF,
64        _: &Self::LayoutState,
65        _: &Self::PaintState,
66        _: &MeasurementContext,
67    ) -> Option<RectF> {
68        None
69    }
70
71    fn debug(
72        &self,
73        bounds: RectF,
74        _: &Self::LayoutState,
75        _: &Self::PaintState,
76        _: &DebugContext,
77    ) -> json::Value {
78        json!({"type": "Canvas", "bounds": bounds.to_json()})
79    }
80}