feat: impl Widget for &BarChart (#897)

BarChart had some internal mutations that needed to be removed to
implement the Widget trait for &BarChart to bring it in line with the
other widgets.

src/widgets/barchart.rs

@@ -313,7 +313,7 @@ struct LabelInfo {
     height: u16,
 }
 
-impl<'a> BarChart<'a> {
+impl BarChart<'_> {
     /// Returns the visible bars length in ticks. A cell contains 8 ticks.
     /// `available_space` used to calculate how many bars can fit in the space
     /// `bar_max_length` is the maximal length a bar can take.
@@ -392,7 +392,7 @@ impl<'a> BarChart<'a> {
         }
     }
 
-    fn render_horizontal(self, buf: &mut Buffer, area: Rect) {
+    fn render_horizontal(&self, buf: &mut Buffer, area: Rect) {
         // get the longest label
         let label_size = self
             .data
@@ -417,10 +417,8 @@ impl<'a> BarChart<'a> {
 
         // print all visible bars, label and values
         let mut bar_y = bars_area.top();
-        for (ticks_vec, mut group) in group_ticks.into_iter().zip(self.data) {
-            let bars = std::mem::take(&mut group.bars);
-
-            for (ticks, bar) in ticks_vec.into_iter().zip(bars) {
+        for (ticks_vec, group) in group_ticks.into_iter().zip(self.data.iter()) {
+            for (ticks, bar) in ticks_vec.into_iter().zip(group.bars.iter()) {
                 let bar_length = (ticks / 8) as u16;
                 let bar_style = self.bar_style.patch(bar.style);
 
@@ -473,7 +471,7 @@ impl<'a> BarChart<'a> {
         }
     }
 
-    fn render_vertical(self, buf: &mut Buffer, area: Rect) {
+    fn render_vertical(&self, buf: &mut Buffer, area: Rect) {
         let label_info = self.label_info(area.height - 1);
 
         let bars_area = Rect {
@@ -535,7 +533,7 @@ impl<'a> BarChart<'a> {
     }
 
     fn render_labels_and_values(
-        self,
+        &self,
         area: Rect,
         buf: &mut Buffer,
         label_info: LabelInfo,
@@ -544,12 +542,10 @@ impl<'a> BarChart<'a> {
         // print labels and values in one go
         let mut bar_x = area.left();
         let bar_y = area.bottom() - label_info.height - 1;
-        for (mut group, ticks_vec) in self.data.into_iter().zip(group_ticks) {
+        for (group, ticks_vec) in self.data.iter().zip(group_ticks) {
             if group.bars.is_empty() {
                 continue;
             }
-            let bars = std::mem::take(&mut group.bars);
-
             // print group labels under the bars or the previous labels
             if label_info.group_label_visible {
                 let label_max_width =
@@ -564,7 +560,7 @@ impl<'a> BarChart<'a> {
             }
 
             // print the bar values and numbers
-            for (mut bar, ticks) in bars.into_iter().zip(ticks_vec) {
+            for (bar, ticks) in group.bars.iter().zip(ticks_vec) {
                 if label_info.bar_label_visible {
                     bar.render_label(buf, self.bar_width, bar_x, bar_y + 1, self.label_style);
                 }
@@ -579,6 +575,12 @@ impl<'a> BarChart<'a> {
 }
 
 impl Widget for BarChart<'_> {
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        (&self).render(area, buf);
+    }
+}
+
+impl Widget for &BarChart<'_> {
     fn render(self, area: Rect, buf: &mut Buffer) {
         buf.set_style(area, self.style);
 

src/widgets/barchart/bar.rs

@@ -147,7 +147,7 @@ impl<'a> Bar<'a> {
     }
 
     pub(super) fn render_value(
-        self,
+        &self,
         buf: &mut Buffer,
         max_width: u16,
         x: u16,
@@ -156,12 +156,8 @@ impl<'a> Bar<'a> {
         ticks: u64,
     ) {
         if self.value != 0 {
-            let value_label = if let Some(text) = self.text_value {
-                text
-            } else {
-                self.value.to_string()
-            };
-
+            let value = self.value.to_string();
+            let value_label = self.text_value.as_ref().unwrap_or(&value);
             let width = value_label.width() as u16;
             const TICKS_PER_LINE: u64 = 8;
             // if we have enough space or the ticks are greater equal than 1 cell (8)
@@ -178,25 +174,29 @@ impl<'a> Bar<'a> {
     }
 
     pub(super) fn render_label(
-        &mut self,
+        &self,
         buf: &mut Buffer,
         max_width: u16,
         x: u16,
         y: u16,
         default_label_style: Style,
     ) {
-        if let Some(label) = &mut self.label {
-            // patch label styles
-            for span in &mut label.spans {
-                span.style = default_label_style.patch(span.style);
-            }
-
-            buf.set_line(
-                x + (max_width.saturating_sub(label.width() as u16) >> 1),
-                y,
-                label,
-                max_width,
-            );
+        // center the label. Necessary to do it this way as we don't want to set the style
+        // of the whole area, just the label area
+        let width = self
+            .label
+            .as_ref()
+            .map_or(0, Line::width)
+            .min(max_width as usize) as u16;
+        let area = Rect {
+            x: x + (max_width.saturating_sub(width)) / 2,
+            y,
+            width,
+            height: 1,
+        };
+        buf.set_style(area, default_label_style);
+        if let Some(label) = &self.label {
+            label.render(area, buf);
         }
     }
 }

src/widgets/barchart/bar_group.rs

@@ -40,20 +40,26 @@ impl<'a> BarGroup<'a> {
         self.bars.iter().max_by_key(|v| v.value).map(|v| v.value)
     }
 
-    pub(super) fn render_label(self, buf: &mut Buffer, area: Rect, default_label_style: Style) {
-        if let Some(mut label) = self.label {
-            // patch label styles
-            for span in &mut label.spans {
-                span.style = default_label_style.patch(span.style);
-            }
-
-            let x_offset = match label.alignment {
-                Some(Alignment::Center) => area.width.saturating_sub(label.width() as u16) >> 1,
-                Some(Alignment::Right) => area.width.saturating_sub(label.width() as u16),
-                _ => 0,
+    pub(super) fn render_label(&self, buf: &mut Buffer, area: Rect, default_label_style: Style) {
+        if let Some(label) = &self.label {
+            // align the label. Necessary to do it this way as we don't want to set the style
+            // of the whole area, just the label area
+            let width = label.width() as u16;
+            let area = match label.alignment {
+                Some(Alignment::Center) => Rect {
+                    x: area.x + (area.width.saturating_sub(width)) / 2,
+                    width,
+                    ..area
+                },
+                Some(Alignment::Right) => Rect {
+                    x: area.x + area.width.saturating_sub(width),
+                    width,
+                    ..area
+                },
+                _ => Rect { width, ..area },
             };
-
-            buf.set_line(area.x + x_offset, area.y, &label, area.width);
+            buf.set_style(area, default_label_style);
+            label.render(area, buf);
         }
     }
 }