1use std::borrow::Borrow;
2use std::i32;
3
4use super::{Drawable, PointCollection};
5use crate::style::{FontDesc, FontResult, LayoutBox, TextStyle};
6use plotters_backend::{BackendCoord, DrawingBackend, DrawingErrorKind};
7
8/// A single line text element. This can be owned or borrowed string, dependents on
9/// `String` or `str` moved into.
10pub struct Text<'a, Coord, T: Borrow<str>> {
11 text: T,
12 coord: Coord,
13 style: TextStyle<'a>,
14}
15
16impl<'a, Coord, T: Borrow<str>> Text<'a, Coord, T> {
17 /// Create a new text element
18 /// - `text`: The text for the element
19 /// - `points`: The upper left conner for the text element
20 /// - `style`: The text style
21 /// - Return the newly created text element
22 pub fn new<S: Into<TextStyle<'a>>>(text: T, points: Coord, style: S) -> Self {
23 Self {
24 text,
25 coord: points,
26 style: style.into(),
27 }
28 }
29}
30
31impl<'b, 'a, Coord: 'a, T: Borrow<str> + 'a> PointCollection<'a, Coord> for &'a Text<'b, Coord, T> {
32 type Point = &'a Coord;
33 type IntoIter = std::iter::Once<&'a Coord>;
34 fn point_iter(self) -> Self::IntoIter {
35 std::iter::once(&self.coord)
36 }
37}
38
39impl<'a, Coord: 'a, DB: DrawingBackend, T: Borrow<str>> Drawable<DB> for Text<'a, Coord, T> {
40 fn draw<I: Iterator<Item = BackendCoord>>(
41 &self,
42 mut points: I,
43 backend: &mut DB,
44 _: (u32, u32),
45 ) -> Result<(), DrawingErrorKind<DB::ErrorType>> {
46 if let Some(a) = points.next() {
47 return backend.draw_text(self.text.borrow(), &self.style, a);
48 }
49 Ok(())
50 }
51}
52
53/// An multi-line text element. The `Text` element allows only single line text
54/// and the `MultiLineText` supports drawing multiple lines
55pub struct MultiLineText<'a, Coord, T: Borrow<str>> {
56 lines: Vec<T>,
57 coord: Coord,
58 style: TextStyle<'a>,
59 line_height: f64,
60}
61
62impl<'a, Coord, T: Borrow<str>> MultiLineText<'a, Coord, T> {
63 /// Create an empty multi-line text element.
64 /// Lines can be append to the empty multi-line by calling `push_line` method
65 ///
66 /// `pos`: The upper left corner
67 /// `style`: The style of the text
68 pub fn new<S: Into<TextStyle<'a>>>(pos: Coord, style: S) -> Self {
69 MultiLineText {
70 lines: vec![],
71 coord: pos,
72 style: style.into(),
73 line_height: 1.25,
74 }
75 }
76
77 /// Set the line height of the multi-line text element
78 pub fn set_line_height(&mut self, value: f64) -> &mut Self {
79 self.line_height = value;
80 self
81 }
82
83 /// Push a new line into the given multi-line text
84 /// `line`: The line to be pushed
85 pub fn push_line<L: Into<T>>(&mut self, line: L) {
86 self.lines.push(line.into());
87 }
88
89 /// Estimate the multi-line text element's dimension
90 pub fn estimate_dimension(&self) -> FontResult<(i32, i32)> {
91 let (mut mx, mut my) = (0, 0);
92
93 for ((x, y), t) in self.layout_lines((0, 0)).zip(self.lines.iter()) {
94 let (dx, dy) = self.style.font.box_size(t.borrow())?;
95 mx = mx.max(x + dx as i32);
96 my = my.max(y + dy as i32);
97 }
98
99 Ok((mx, my))
100 }
101
102 /// Move the location to the specified location
103 pub fn relocate(&mut self, coord: Coord) {
104 self.coord = coord
105 }
106
107 fn layout_lines(&self, (x0, y0): BackendCoord) -> impl Iterator<Item = BackendCoord> {
108 let font_height = self.style.font.get_size();
109 let actual_line_height = font_height * self.line_height;
110 (0..self.lines.len() as u32).map(move |idx| {
111 let y = f64::from(y0) + f64::from(idx) * actual_line_height;
112 // TODO: Support text alignment as well, currently everything is left aligned
113 let x = f64::from(x0);
114 (x.round() as i32, y.round() as i32)
115 })
116 }
117}
118
119fn layout_multiline_text<'a, F: FnMut(&'a str)>(
120 text: &'a str,
121 max_width: u32,
122 font: FontDesc<'a>,
123 mut func: F,
124) {
125 for line in text.lines() {
126 if max_width == 0 || line.is_empty() {
127 func(line);
128 } else {
129 let mut remaining = &line[0..];
130
131 while !remaining.is_empty() {
132 let mut left = 0;
133 while left < remaining.len() {
134 let width = font.box_size(&remaining[0..=left]).unwrap_or((0, 0)).0 as i32;
135
136 if width > max_width as i32 {
137 break;
138 }
139 left += 1;
140 }
141
142 if left == 0 {
143 left += 1;
144 }
145
146 let cur_line = &remaining[..left];
147 remaining = &remaining[left..];
148
149 func(cur_line);
150 }
151 }
152 }
153}
154
155impl<'a, T: Borrow<str>> MultiLineText<'a, BackendCoord, T> {
156 /// Compute the line layout
157 pub fn compute_line_layout(&self) -> FontResult<Vec<LayoutBox>> {
158 let mut ret = vec![];
159 for ((x, y), t) in self.layout_lines(self.coord).zip(self.lines.iter()) {
160 let (dx, dy) = self.style.font.box_size(t.borrow())?;
161 ret.push(((x, y), (x + dx as i32, y + dy as i32)));
162 }
163 Ok(ret)
164 }
165}
166
167impl<'a, Coord> MultiLineText<'a, Coord, &'a str> {
168 /// Parse a multi-line text into an multi-line element.
169 ///
170 /// `text`: The text that is parsed
171 /// `pos`: The position of the text
172 /// `style`: The style for this text
173 /// `max_width`: The width of the multi-line text element, the line will break
174 /// into two lines if the line is wider than the max_width. If 0 is given, do not
175 /// do any line wrapping
176 pub fn from_str<ST: Into<&'a str>, S: Into<TextStyle<'a>>>(
177 text: ST,
178 pos: Coord,
179 style: S,
180 max_width: u32,
181 ) -> Self {
182 let text = text.into();
183 let mut ret = MultiLineText::new(pos, style);
184
185 layout_multiline_text(text, max_width, ret.style.font.clone(), |l| {
186 ret.push_line(l)
187 });
188 ret
189 }
190}
191
192impl<'a, Coord> MultiLineText<'a, Coord, String> {
193 /// Parse a multi-line text into an multi-line element.
194 ///
195 /// `text`: The text that is parsed
196 /// `pos`: The position of the text
197 /// `style`: The style for this text
198 /// `max_width`: The width of the multi-line text element, the line will break
199 /// into two lines if the line is wider than the max_width. If 0 is given, do not
200 /// do any line wrapping
201 pub fn from_string<S: Into<TextStyle<'a>>>(
202 text: String,
203 pos: Coord,
204 style: S,
205 max_width: u32,
206 ) -> Self {
207 let mut ret = MultiLineText::new(pos, style);
208
209 layout_multiline_text(text.as_str(), max_width, ret.style.font.clone(), |l| {
210 ret.push_line(l.to_string())
211 });
212 ret
213 }
214}
215
216impl<'b, 'a, Coord: 'a, T: Borrow<str> + 'a> PointCollection<'a, Coord>
217 for &'a MultiLineText<'b, Coord, T>
218{
219 type Point = &'a Coord;
220 type IntoIter = std::iter::Once<&'a Coord>;
221 fn point_iter(self) -> Self::IntoIter {
222 std::iter::once(&self.coord)
223 }
224}
225
226impl<'a, Coord: 'a, DB: DrawingBackend, T: Borrow<str>> Drawable<DB>
227 for MultiLineText<'a, Coord, T>
228{
229 fn draw<I: Iterator<Item = BackendCoord>>(
230 &self,
231 mut points: I,
232 backend: &mut DB,
233 _: (u32, u32),
234 ) -> Result<(), DrawingErrorKind<DB::ErrorType>> {
235 if let Some(a) = points.next() {
236 for (point, text) in self.layout_lines(a).zip(self.lines.iter()) {
237 backend.draw_text(text.borrow(), &self.style, point)?;
238 }
239 }
240 Ok(())
241 }
242}
243