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

use super::ChartContext;
use crate::coord::CoordTranslate;
use crate::drawing::backend::{BackendCoord, DrawingErrorKind};
use crate::drawing::{DrawingAreaErrorKind, DrawingBackend};
use crate::element::{EmptyElement, IntoDynElement, MultiLineText, Rectangle};
use crate::style::{IntoFont, ShapeStyle, TextStyle, Transparent};

pub enum SeriesLabelPosition {
    UpperRight,
    MiddleRight,
    LowerRight,
    Coordinate(i32, i32),
}

impl SeriesLabelPosition {
    fn layout_label_area(&self, label_dim: (i32, i32), area_dim: (u32, u32)) -> (i32, i32) {
        match self {
            SeriesLabelPosition::UpperRight => (area_dim.0 as i32 - label_dim.0 as i32, 0),
            SeriesLabelPosition::MiddleRight => (
                area_dim.0 as i32 - label_dim.0 as i32,
                (area_dim.1 as i32 - label_dim.1 as i32) / 2,
            ),
            SeriesLabelPosition::LowerRight => (
                area_dim.0 as i32 - label_dim.0 as i32,
                area_dim.1 as i32 - label_dim.1 as i32,
            ),
            SeriesLabelPosition::Coordinate(x, y) => (*x, *y),
        }
    }
}

/// The struct to sepcify the series label of a target chart context
pub struct SeriesLabelStyle<'a, 'b, DB: DrawingBackend, CT: CoordTranslate> {
    target: &'b mut ChartContext<'a, DB, CT>,
    position: SeriesLabelPosition,
    legend_area_size: u32,
    border_style: ShapeStyle,
    background: ShapeStyle,
    label_font: Option<TextStyle<'b>>,
    margin: u32,
}

impl<'a, 'b, DB: DrawingBackend + 'a, CT: CoordTranslate> SeriesLabelStyle<'a, 'b, DB, CT> {
    pub(super) fn new(target: &'b mut ChartContext<'a, DB, CT>) -> Self {
        Self {
            target,
            position: SeriesLabelPosition::MiddleRight,
            legend_area_size: 30,
            border_style: (&Transparent).into(),
            background: (&Transparent).into(),
            label_font: None,
            margin: 10,
        }
    }

    /// Set the series label positioning style
    /// `pos` - The positioning style
    pub fn position(&mut self, pos: SeriesLabelPosition) -> &mut Self {
        self.position = pos;
        self
    }

    pub fn margin(&mut self, value: u32) -> &mut Self {
        self.margin = value;
        self
    }

    /// Set the size of legend area
    /// `size` - The size of legend area in pixel
    pub fn legend_area_size(&mut self, size: u32) -> &mut Self {
        self.legend_area_size = size;
        self
    }

    /// Set the style of the label series area
    /// `style` - The style of the border
    pub fn border_style<S: Into<ShapeStyle>>(&mut self, style: S) -> &mut Self {
        self.border_style = style.into();
        self
    }

    /// Set the background style
    /// `style` - The style of the border
    pub fn background_style<S: Into<ShapeStyle>>(&mut self, style: S) -> &mut Self {
        self.background = style.into();
        self
    }

    /// Set the series label font
    /// `font` - The font
    pub fn label_font<F: Into<TextStyle<'b>>>(&mut self, font: F) -> &mut Self {
        self.label_font = Some(font.into());
        self
    }

    /// Draw the series label area
    pub fn draw(&mut self) -> Result<(), DrawingAreaErrorKind<DB::ErrorType>> {
        let drawing_area = self.target.plotting_area().strip_coord_spec();
        let default_font = ("Arial", 12).into_font();
        let default_style: TextStyle = default_font.into();

        let font = {
            let mut temp = None;
            std::mem::swap(&mut self.label_font, &mut temp);
            temp.unwrap_or(default_style)
        };

        let mut label_element = MultiLineText::<_, &str>::new((0, 0), &font);
        let mut funcs = vec![];

        for anno in self.target.series_anno.iter() {
            let label_text = anno.get_label();
            let draw_func = anno.get_draw_func();

            if label_text == "" && draw_func.is_none() {
                continue;
            }

            funcs.push(
                draw_func.unwrap_or_else(|| &|p: BackendCoord| EmptyElement::at(p).into_dyn()),
            );
            label_element.push_line(label_text);
        }

        let (mut w, mut h) = label_element
            .estimate_dimension()
            .map_err(|e| DrawingAreaErrorKind::BackendError(DrawingErrorKind::FontError(e)))?;

        let margin = self.margin as i32;

        w += self.legend_area_size as i32 + margin * 2;
        h += margin * 2;

        let (area_w, area_h) = drawing_area.dim_in_pixel();

        let (label_x, label_y) = self.position.layout_label_area((w, h), (area_w, area_h));

        label_element.relocate((
            label_x + self.legend_area_size as i32 + margin,
            label_y + margin,
        ));

        drawing_area.draw(&Rectangle::new(
            [(label_x, label_y), (label_x + w, label_y + h)],
            self.background.filled(),
        ))?;
        drawing_area.draw(&Rectangle::new(
            [(label_x, label_y), (label_x + w, label_y + h)],
            self.border_style.clone(),
        ))?;
        drawing_area.draw(&label_element)?;

        for (((_, y0), (_, y1)), make_elem) in label_element
            .compute_line_layout()
            .map_err(|e| DrawingAreaErrorKind::BackendError(DrawingErrorKind::FontError(e)))?
            .into_iter()
            .zip(funcs.into_iter())
        {
            let legend_element = make_elem((label_x + margin, (y0 + y1) / 2));
            drawing_area.draw(&legend_element)?;
        }

        Ok(())
    }
}