1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
//! Direct2D rasteriser for [`crate::Scrollbar`].
//!
//! Painting is implemented in the shared
//! [`crate::primitives::scrollbar::native_surface_paint::paint`] — see that
//! function's documentation for implementation details.
//!
//! `super::multi_section_view`'s embedded scrollbar uses its own
//! CPU-premix convention — see that module's documentation.
//!
//! Only compiled on `target_os = "windows"` — see `super::mod`'s
//! `#[cfg(target_os = "windows")] mod scrollbar;` and `backend.rs`'s
//! module docs for why the rest of this repo's `--features win` compile
//! gate stays meaningful without a Windows host.
#[cfg(test)]
use crate::primitives::scrollbar::Scrollbar;
#[cfg(test)]
use crate::theme::Theme;
#[cfg(test)]
mod tests {
use super::*;
use crate::event::Rect;
use crate::types::{Color, WidgetId};
use crate::win::testing::HeadlessSurface;
const W: u32 = 80;
const H: u32 = 200;
/// Paint `scrollbar` via the shared
/// [`crate::primitives::scrollbar::native_surface_paint::paint`]
/// through a [`super::super::surface::D2dSurface`] over `surface`'s
/// headless target — the same adapter the now-removed
/// `draw_scrollbar` shim used, exercised here
/// directly.
fn paint(scrollbar: &Scrollbar) -> HeadlessSurface {
let surface = HeadlessSurface::new(W, H).expect("create surface");
// Fill with a known background so blended track/thumb colours
// are deterministic to probe.
surface
.fill_rect(
Rect::new(0.0, 0.0, W as f32, H as f32),
Theme::default().background,
)
.expect("fill bg");
surface
.paint(|target| {
let mut raw = super::super::surface::D2dSurface {
target,
dwrite: None,
};
crate::primitives::scrollbar::native_surface_paint::paint(
scrollbar,
&mut raw,
&Theme::default(),
);
})
.expect("paint scrollbar");
surface
}
fn vertical_bar(scroll: f32, total: f32, visible: f32) -> Scrollbar {
Scrollbar::vertical(
WidgetId::new("sb"),
Rect::new(0.0, 0.0, 8.0, H as f32),
scroll,
total,
visible,
20.0,
)
}
/// Reference alpha blend, independent of production code, for
/// computing the expected pixel colour in
/// [`track_blends_with_real_background_not_theme_background`].
fn expected_alpha_blend(base: Color, over: Color, alpha: f32) -> Color {
let mix =
|b: u8, o: u8| -> u8 { (b as f32 * (1.0 - alpha) + o as f32 * alpha).round() as u8 };
Color::rgb(
mix(base.r, over.r),
mix(base.g, over.g),
mix(base.b, over.b),
)
}
/// The scrollbar track blends correctly with the actual background
/// beneath it, not with the theme background. This ensures the track
/// color is alpha-blended with whatever content is actually underneath
/// (editor, terminal, panel header, etc.), not with a premixed theme
/// background color.
#[test]
fn track_blends_with_real_background_not_theme_background() {
let sb = vertical_bar(0.0, 200.0, 50.0);
let theme = Theme::default();
let real_bg = Color::rgb(200, 30, 30);
assert_ne!(
(real_bg.r, real_bg.g, real_bg.b),
(theme.background.r, theme.background.g, theme.background.b),
"test fixture must differ from theme.background to be a meaningful probe",
);
let surface = HeadlessSurface::new(W, H).expect("create surface");
surface
.fill_rect(Rect::new(0.0, 0.0, W as f32, H as f32), real_bg)
.expect("fill bg");
surface
.paint(|target| {
let mut raw = super::super::surface::D2dSurface {
target,
dwrite: None,
};
crate::primitives::scrollbar::native_surface_paint::paint(&sb, &mut raw, &theme);
})
.expect("paint scrollbar");
// Not hovered/dragging: track_alpha = 0.20 (see the shared `paint`).
let track_alpha = 0.20;
let expected = expected_alpha_blend(real_bg, theme.scrollbar_track, track_alpha);
let old_halo = expected_alpha_blend(theme.background, theme.scrollbar_track, track_alpha);
// Probe mid-track, below the thumb (thumb_len ≈ 50px at scroll=0).
let c = surface.pixel_at(4, 120);
assert_eq!(
(c.r, c.g, c.b),
(expected.r, expected.g, expected.b),
"track should alpha-blend with the real background beneath it",
);
assert_ne!(
(c.r, c.g, c.b),
(old_halo.r, old_halo.g, old_halo.b),
"track must not premix against theme.background regardless of what's painted underneath",
);
}
#[test]
fn track_paints_over_background() {
let sb = vertical_bar(0.0, 200.0, 50.0);
let surface = paint(&sb);
let theme = Theme::default();
// Probe mid-track at a y the thumb does NOT cover (thumb sits
// at the top with thumb_len ≈ 50px when scroll=0).
let c = surface.pixel_at(4, 120);
assert_ne!(
(c.r, c.g, c.b),
(theme.background.r, theme.background.g, theme.background.b),
"track should paint something other than plain background",
);
}
#[test]
fn thumb_paints_differently_than_track_only_zone() {
let sb = vertical_bar(0.0, 200.0, 50.0);
let surface = paint(&sb);
// Thumb at top: probe inside thumb_len.
let thumb_px = surface.pixel_at(4, 5);
// Track only: probe well below the thumb.
let track_px = surface.pixel_at(4, 150);
assert_ne!(
(thumb_px.r, thumb_px.g, thumb_px.b),
(track_px.r, track_px.g, track_px.b),
"thumb zone should differ from a track-only zone",
);
}
#[test]
fn dragging_makes_thumb_more_opaque() {
let mut sb = vertical_bar(0.0, 200.0, 50.0);
let normal = paint(&sb).pixel_at(4, 5);
sb.dragging = true;
let dragging = paint(&sb).pixel_at(4, 5);
assert_ne!(
(normal.r, normal.g, normal.b),
(dragging.r, dragging.g, dragging.b),
"dragging should change the thumb's blended colour",
);
}
#[test]
fn full_scroll_lands_thumb_at_track_bottom() {
// scroll = total - visible should align the thumb's bottom edge
// to the track end.
let sb = vertical_bar(150.0, 200.0, 50.0);
let surface = paint(&sb);
let bottom = surface.pixel_at(4, H - 4);
let mid = surface.pixel_at(4, 80);
assert_ne!(
(bottom.r, bottom.g, bottom.b),
(mid.r, mid.g, mid.b),
"full-scroll: the bottom probe (now inside the thumb) should differ from mid-track",
);
}
#[test]
fn horizontal_orientation_uses_width() {
let track = Rect::new(0.0, 50.0, W as f32, 8.0);
let sb = Scrollbar::horizontal(WidgetId::new("h"), track, 0.0, 200.0, 40.0, 10.0);
let surface = paint(&sb);
// Thumb at left: x ∈ [0, thumb_len) should show thumb;
// x past thumb should show track only.
let left = surface.pixel_at(2, 54);
let right = surface.pixel_at(W - 4, 54);
assert_ne!(
(left.r, left.g, left.b),
(right.r, right.g, right.b),
"horizontal: thumb zone (left) should differ from track-only zone (right)",
);
}
#[test]
fn zero_size_track_is_a_no_op() {
let sb = Scrollbar::vertical(
WidgetId::new("sb"),
Rect::new(0.0, 0.0, 0.0, 0.0),
0.0,
200.0,
50.0,
20.0,
);
// Must not panic (a zero-size fill_rect is a no-op D2D call), and
// must genuinely paint nothing: probe a few points across the
// surface and confirm they're all still the plain background
// `paint()` filled before invoking the scrollbar rasteriser.
let surface = paint(&sb);
let theme = Theme::default();
for (x, y) in [(4, 4), (4, H / 2), (4, H - 4)] {
let c = surface.pixel_at(x, y);
assert_eq!(
(c.r, c.g, c.b),
(theme.background.r, theme.background.g, theme.background.b),
"a zero-size track should paint nothing, leaving the background untouched at ({x}, {y})",
);
}
}
}