ui: Use parsed markdown contents to determine sizing.

helix-term/src/ui/markdown.rs

@@ -21,10 +21,7 @@ impl Markdown {
         Self { contents }
     }
 }
-impl Component for Markdown {
-    fn render(&self, area: Rect, surface: &mut Surface, cx: &mut Context) {
-        use tui::widgets::{Paragraph, Widget, Wrap};
-
+fn parse(contents: &str) -> tui::text::Text {
     use pulldown_cmark::{CodeBlockKind, CowStr, Event, Options, Parser, Tag};
     use tui::text::{Span, Spans, Text};
 
@@ -33,7 +30,7 @@ impl Component for Markdown {
 
     let mut options = Options::empty();
     options.insert(Options::ENABLE_STRIKETHROUGH);
-        let parser = Parser::new_ext(&self.contents, options);
+    let parser = Parser::new_ext(contents, options);
 
     // TODO: if possible, render links as terminal hyperlinks: https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda
     let mut tags = Vec::new();
@@ -43,7 +40,7 @@ impl Component for Markdown {
     fn to_span(text: pulldown_cmark::CowStr) -> Span {
         use std::ops::Deref;
         Span::raw::<std::borrow::Cow<_>>(match text {
-                CowStr::Borrowed(s) => s.into(),
+            CowStr::Borrowed(s) => s.to_string().into(), // could retain borrow
             CowStr::Boxed(s) => s.to_string().into(),
             CowStr::Inlined(s) => s.deref().to_owned().into(),
         })
@@ -59,12 +56,12 @@ impl Component for Markdown {
             Event::End(tag) => {
                 tags.pop();
                 match tag {
-                        Tag::Heading(_)
-                        | Tag::Paragraph
-                        | Tag::CodeBlock(CodeBlockKind::Fenced(_)) => {
+                    Tag::Heading(_) | Tag::Paragraph | Tag::CodeBlock(CodeBlockKind::Fenced(_)) => {
                         // whenever code block or paragraph closes, new line
                         let spans = std::mem::replace(&mut spans, Vec::new());
+                        if !spans.is_empty() {
                             lines.push(Spans::from(spans));
+                        }
                         lines.push(Spans::default());
                     }
                     _ => (),
@@ -110,9 +107,15 @@ impl Component for Markdown {
         lines.push(Spans::from(spans));
     }
 
-        let contents = Text::from(lines);
+    Text::from(lines)
+}
+impl Component for Markdown {
+    fn render(&self, area: Rect, surface: &mut Surface, cx: &mut Context) {
+        use tui::widgets::{Paragraph, Widget, Wrap};
+
+        let text = parse(&self.contents);
 
-        let par = Paragraph::new(contents)
+        let par = Paragraph::new(text)
             .wrap(Wrap { trim: false })
             .scroll((cx.scroll.unwrap_or_default() as u16, 0));
 
@@ -121,7 +124,7 @@ impl Component for Markdown {
     }
 
     fn required_size(&mut self, viewport: (u16, u16)) -> Option<(u16, u16)> {
-        let contents = tui::text::Text::from(self.contents.clone());
+        let contents = parse(&self.contents);
         let padding = 2;
         let width = std::cmp::min(contents.width() as u16 + padding, viewport.0);
         let height = std::cmp::min(contents.height() as u16 + padding, viewport.1);