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
|
use crate::params::{
FONT_SIZE_SCALE_REFERENCE, TextAlign, TextBackground, TextDecoration, TextLayoutParams,
};
pub const TEXT_DECORATION_THICKNESS_RATIO: f64 = 0.07;
pub const STRIKETHROUGH_VERTICAL_RATIO: f64 = 0.35;
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct ResolvedTextLayout {
pub scaled_font_size: f64,
pub letter_spacing: f64,
pub line_height_px: f64,
pub font_size_ratio: f64,
pub text_align: TextAlign,
pub text_decoration: TextDecoration,
}
pub fn resolve_text_layout(text: &TextLayoutParams, canvas_height: f64) -> ResolvedTextLayout {
let scaled_font_size = text.font_size * (canvas_height / FONT_SIZE_SCALE_REFERENCE);
ResolvedTextLayout {
scaled_font_size,
letter_spacing: text.letter_spacing,
line_height_px: scaled_font_size * text.line_height,
font_size_ratio: text.font_size / 15.0,
text_align: text.text_align,
text_decoration: text.text_decoration,
}
}
#[derive(Clone, Copy, Debug, Default, PartialEq)]
pub struct LineMetrics {
pub width: f64,
pub ascent: f64,
pub descent: f64,
}
#[derive(Clone, Copy, Debug, Default, PartialEq)]
pub struct TextBlockMeasurement {
pub visual_center_offset: f64,
pub height: f64,
pub max_width: f64,
}
pub fn measure_text_block(
line_metrics: &[LineMetrics],
line_height_px: f64,
) -> TextBlockMeasurement {
let max_width = line_metrics
.iter()
.fold(0.0_f64, |max, metrics| max.max(metrics.width));
let line_count = line_metrics.len() as f64;
TextBlockMeasurement {
visual_center_offset: ((line_count - 1.0) * line_height_px) / 2.0,
height: line_count * line_height_px,
max_width,
}
}
#[derive(Clone, Copy, Debug, Default, PartialEq)]
pub struct Rect {
pub left: f64,
pub top: f64,
pub width: f64,
pub height: f64,
}
impl Rect {
pub fn right(self) -> f64 {
self.left + self.width
}
pub fn bottom(self) -> f64 {
self.top + self.height
}
}
pub fn align_offset(text_align: TextAlign, line_width: f64) -> f64 {
match text_align {
TextAlign::Left => 0.0,
TextAlign::Center => -line_width / 2.0,
TextAlign::Right => -line_width,
}
}
pub fn text_rect(text_align: TextAlign, block: &TextBlockMeasurement) -> Rect {
Rect {
left: align_offset(text_align, block.max_width),
top: -block.height / 2.0,
width: block.max_width,
height: block.height,
}
}
fn background_visible(background: &TextBackground) -> bool {
background.enabled && !background.color.is_empty() && background.color != "transparent"
}
pub fn text_background_rect(
text_align: TextAlign,
block: &TextBlockMeasurement,
background: &TextBackground,
font_size_ratio: f64,
) -> Option<Rect> {
if !background_visible(background) {
return None;
}
let rect = text_rect(text_align, block);
let padding_x = background.padding_x * font_size_ratio;
let padding_y = background.padding_y * font_size_ratio;
Some(Rect {
left: rect.left - padding_x + background.offset_x,
top: rect.top - padding_y + background.offset_y,
width: rect.width + padding_x * 2.0,
height: rect.height + padding_y * 2.0,
})
}
pub fn text_visual_rect(
text_align: TextAlign,
block: &TextBlockMeasurement,
background: &TextBackground,
font_size_ratio: f64,
) -> Rect {
let rect = text_rect(text_align, block);
let Some(background_rect) = text_background_rect(text_align, block, background, font_size_ratio)
else {
return rect;
};
let left = rect.left.min(background_rect.left);
let top = rect.top.min(background_rect.top);
Rect {
left,
top,
width: rect.right().max(background_rect.right()) - left,
height: rect.bottom().max(background_rect.bottom()) - top,
}
}
pub fn decoration_rect(
text_decoration: TextDecoration,
text_align: TextAlign,
line_width: f64,
line_y: f64,
ascent: f64,
descent: f64,
scaled_font_size: f64,
) -> Option<Rect> {
if text_decoration == TextDecoration::None {
return None;
}
let thickness = (scaled_font_size * TEXT_DECORATION_THICKNESS_RATIO).max(1.0);
let top = match text_decoration {
TextDecoration::Underline => line_y + descent + thickness,
TextDecoration::LineThrough => line_y - (ascent - descent) * STRIKETHROUGH_VERTICAL_RATIO,
TextDecoration::None => unreachable!(),
};
Some(Rect {
left: align_offset(text_align, line_width),
top,
width: line_width,
height: thickness,
})
}
|
