papergrid/estimation/
width.rs

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
//! The module contains a [`WidthEstimator`] for [`Grid`] width estimation.
//!
//! [`Grid`]: crate::Grid

use std::cmp::Ordering;

use crate::{records::Records, GridConfig, Position};

use super::Estimate;

pub use super::width_func::{CfgWidthFunction, WidthFunc};

/// A [`Estimate`]or of a width for a [`Grid`].
///
/// [`Grid`]: crate::Grid
#[derive(Debug, Default, Clone, PartialEq, Eq)]
pub struct WidthEstimator {
    widths: Vec<usize>,
}

impl<R> Estimate<R> for WidthEstimator
where
    R: Records,
{
    fn estimate(&mut self, records: R, cfg: &GridConfig) {
        let width_ctrl = CfgWidthFunction::from_cfg(cfg);
        self.widths = build_widths(&records, cfg, &width_ctrl);
    }

    fn get(&self, column: usize) -> Option<usize> {
        self.widths.get(column).copied()
    }

    fn total(&self) -> usize {
        self.widths.iter().sum()
    }
}

impl From<Vec<usize>> for WidthEstimator {
    fn from(widths: Vec<usize>) -> Self {
        Self { widths }
    }
}

impl From<WidthEstimator> for Vec<usize> {
    fn from(val: WidthEstimator) -> Self {
        val.widths
    }
}

fn build_widths<R>(records: &R, cfg: &GridConfig, width_ctrl: &CfgWidthFunction) -> Vec<usize>
where
    R: Records,
{
    let shape = (records.count_rows(), records.count_columns());
    let mut widths = vec![0; records.count_columns()];
    for (col, column) in widths.iter_mut().enumerate() {
        let max = (0..records.count_rows())
            .filter(|&row| is_simple_cell(cfg, (row, col), shape))
            .map(|row| get_cell_width(cfg, records, (row, col), width_ctrl))
            .max()
            .unwrap_or(0);

        *column = max;
    }

    adjust_spans(cfg, width_ctrl, records, &mut widths);

    widths
}

fn adjust_spans<R>(
    cfg: &GridConfig,
    width_ctrl: &CfgWidthFunction,
    records: &R,
    widths: &mut [usize],
) where
    R: Records,
{
    if !cfg.has_column_spans() {
        return;
    }

    // The overall width disctribution will be different depend on the order.
    //
    // We sort spans in order to prioritize the smaller spans first.
    let mut spans = cfg
        .iter_column_spans((records.count_rows(), records.count_columns()))
        .collect::<Vec<_>>();
    spans.sort_unstable_by(|a, b| match a.1.cmp(&b.1) {
        Ordering::Equal => a.0.cmp(&b.0),
        o => o,
    });

    // todo: the order is matter here; we need to figure out what is correct.
    for ((row, col), span) in spans {
        adjust_range(cfg, width_ctrl, records, row, col, col + span, widths);
    }
}

fn adjust_range<R>(
    cfg: &GridConfig,
    width_ctrl: &CfgWidthFunction,
    records: &R,
    row: usize,
    start: usize,
    end: usize,
    widths: &mut [usize],
) where
    R: Records,
{
    let max_span_width = get_cell_width(cfg, records, (row, start), width_ctrl);
    let range_width = range_width(cfg, start, end, widths);

    if range_width >= max_span_width {
        return;
    }

    inc_range_width(widths, max_span_width - range_width, start, end);
}

fn inc_range_width(widths: &mut [usize], size: usize, start: usize, end: usize) {
    if widths.is_empty() {
        return;
    }

    let span = end - start;
    let one = size / span;
    let rest = size - span * one;

    let mut i = start;
    while i < end {
        if i == start {
            widths[i] += one + rest;
        } else {
            widths[i] += one;
        }

        i += 1;
    }
}

fn is_simple_cell(cfg: &GridConfig, pos: Position, shape: (usize, usize)) -> bool {
    cfg.is_cell_visible(pos, shape) && matches!(cfg.get_column_span(pos, shape), None | Some(1))
}

fn get_cell_width<R>(
    cfg: &GridConfig,
    records: &R,
    pos: Position,
    width_ctrl: &CfgWidthFunction,
) -> usize
where
    R: Records,
{
    let width = records.get_width(pos, width_ctrl);
    let padding = get_cell_padding(cfg, pos);
    width + padding
}

fn get_cell_padding(cfg: &GridConfig, pos: Position) -> usize {
    let padding = cfg.get_padding(pos.into());
    padding.left.size + padding.right.size
}

fn range_width(grid: &GridConfig, start: usize, end: usize, widths: &[usize]) -> usize {
    let count_borders = count_borders_in_range(grid, start, end, widths.len());
    let range_width = widths[start..end].iter().sum::<usize>();
    count_borders + range_width
}

fn count_borders_in_range(
    cfg: &GridConfig,
    start: usize,
    end: usize,
    count_columns: usize,
) -> usize {
    (start..end)
        .skip(1)
        .filter(|&i| cfg.has_vertical(i, count_columns))
        .count()
}