takumi 1.7.0

Render UI component trees to images.
Documentation 
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

use std::{borrow::Cow, collections::HashMap};

use cssparser::{Parser, ParserInput, Token};

use super::DeferredDeclaration;
use crate::layout::style::{ComputedStyle, CssInput};

pub(super) fn resolve_var_function(
  input: &mut Parser<'_, '_>,
  custom_properties: &HashMap<String, String>,
  stack: &mut Vec<String>,
) -> Option<String> {
  let property_name = input.expect_ident_cloned().ok()?;
  if !property_name.starts_with("--") {
    return None;
  }

  let fallback = if input.try_parse(Parser::expect_comma).is_ok() {
    let mut output = String::new();
    resolve_var_tokens_into(input, custom_properties, stack, &mut output)?;
    Some(output)
  } else {
    None
  };

  if input.next_including_whitespace_and_comments().is_ok() {
    return None;
  }

  if stack.iter().any(|entry| entry == property_name.as_ref()) {
    return fallback;
  }

  let resolved = if let Some(specified_value) = custom_properties.get(property_name.as_ref()) {
    stack.push(property_name.to_string());
    let resolved = resolve_var_references(specified_value, custom_properties, stack);
    stack.pop();
    resolved
  } else {
    None
  };

  resolved.or(fallback)
}

fn resolve_var_tokens_into(
  input: &mut Parser<'_, '_>,
  custom_properties: &HashMap<String, String>,
  stack: &mut Vec<String>,
  output: &mut String,
) -> Option<()> {
  while !input.is_exhausted() {
    let start = input.position();
    let token = input.next_including_whitespace_and_comments().ok()?;

    match token {
      Token::Function(name) if name.eq_ignore_ascii_case("var") => {
        output.push_str(
          &input
            .parse_nested_block(|input| {
              resolve_var_function(input, custom_properties, stack)
                .ok_or_else(|| input.new_error_for_next_token::<()>())
            })
            .ok()?,
        );
      }
      Token::Function(name) => {
        output.push_str(name);
        output.push('(');
        input
          .parse_nested_block(|input| {
            resolve_var_tokens_into(input, custom_properties, stack, output)
              .ok_or_else(|| input.new_error_for_next_token::<()>())
          })
          .ok()?;
        output.push(')');
      }
      Token::ParenthesisBlock => {
        output.push('(');
        input
          .parse_nested_block(|input| {
            resolve_var_tokens_into(input, custom_properties, stack, output)
              .ok_or_else(|| input.new_error_for_next_token::<()>())
          })
          .ok()?;
        output.push(')');
      }
      Token::SquareBracketBlock => {
        output.push('[');
        input
          .parse_nested_block(|input| {
            resolve_var_tokens_into(input, custom_properties, stack, output)
              .ok_or_else(|| input.new_error_for_next_token::<()>())
          })
          .ok()?;
        output.push(']');
      }
      Token::CurlyBracketBlock => {
        output.push('{');
        input
          .parse_nested_block(|input| {
            resolve_var_tokens_into(input, custom_properties, stack, output)
              .ok_or_else(|| input.new_error_for_next_token::<()>())
          })
          .ok()?;
        output.push('}');
      }
      _ => output.push_str(input.slice_from(start)),
    }
  }

  Some(())
}

pub(crate) fn resolve_var_references(
  specified_value: &str,
  custom_properties: &HashMap<String, String>,
  stack: &mut Vec<String>,
) -> Option<String> {
  let mut parser_input = ParserInput::new(specified_value);
  let mut parser = Parser::new(&mut parser_input);
  let mut output = String::with_capacity(specified_value.len());
  resolve_var_tokens_into(&mut parser, custom_properties, stack, &mut output)?;
  Some(output)
}

pub(super) fn apply_deferred_declaration(
  style: &mut ComputedStyle,
  parent: Option<&ComputedStyle>,
  deferred: &DeferredDeclaration,
) {
  let Some(resolved_value) = resolve_var_references(
    &deferred.specified_value,
    &style.custom_properties,
    &mut Vec::new(),
  ) else {
    return;
  };

  let declarations = deferred
    .property
    .parse_css_input_declarations(CssInput::Str(Cow::Owned(resolved_value)))
    .ok();

  let Some(declarations) = declarations else {
    return;
  };

  for declaration in declarations {
    match parent {
      Some(parent) => declaration.apply_with_parent(style, parent),
      None => declaration.apply_to_computed(style),
    }
  }
}