Fix space handling for multiline 🔨

4 files changed, 76 insertions, 32 deletions

diff --git a/src/doc.rs b/src/doc.rs
index 3e060f6e..a3bdfeb6 100644
--- a/src/doc.rs
+++ b/src/doc.rs
@@ -15,10 +15,19 @@ pub struct Document {
 /// Default styles for a document.
 #[derive(Debug, Clone, PartialEq)]
 pub struct Style {
-    /// The width and height of the paper.
-    pub paper_size: [Size; 2],
-    /// The [left, top, right, bottom] margins of the paper.
-    pub margins: [Size; 4],
+    /// The width of the paper.
+    pub width: Size,
+    /// The height of the paper.
+    pub height: Size,
+
+    /// The left margin of the paper.
+    pub margin_left: Size,
+    /// The top margin of the paper.
+    pub margin_top: Size,
+    /// The right margin of the paper.
+    pub margin_right: Size,
+    /// The bottom margin of the paper.
+    pub margin_bottom: Size,
 
     /// A fallback list of font families to use.
     pub font_families: Vec<String>,
@@ -31,9 +40,15 @@ pub struct Style {
 impl Default for Style {
     fn default() -> Style {
         Style {
-            // A4 paper with 1.5 cm margins in all directions
-            paper_size: [Size::from_mm(210.0), Size::from_mm(297.0)],
-            margins: [Size::from_cm(2.5); 4],
+            // A4 paper
+            width: Size::from_mm(210.0),
+            height: Size::from_mm(297.0),
+
+            // A bit more on top and bottom
+            margin_left: Size::from_cm(2.5),
+            margin_top: Size::from_cm(3.0),
+            margin_right: Size::from_cm(2.5),
+            margin_bottom: Size::from_cm(3.0),
 
             // Default font family
             font_families: (&[
@@ -48,8 +63,10 @@ impl Default for Style {
 /// A page with text contents in a document.
 #[derive(Debug, Clone, PartialEq)]
 pub struct Page {
-    /// The width and height of the page.
-    pub size: [Size; 2],
+    /// The width of the page.
+    pub width: Size,
+    /// The height of the page.
+    pub height: Size,
     /// Text content on the page.
     pub text: Vec<Text>,
 }
diff --git a/src/engine.rs b/src/engine.rs
index ef50ecb4..2fbb830b 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -24,9 +24,9 @@ pub struct Engine<'s> {
 
 impl<'s> Engine<'s> {
     /// Create a new generator from a syntax tree.
-    pub fn new(tree: &'s SyntaxTree<'s>) -> Engine<'s> {
+    pub fn new(tree: &'s SyntaxTree<'s>, style: Style) -> Engine<'s> {
         Engine {
-            style: Style::default(),
+            style,
             tree,
             fonts: Vec::new(),
             active_font: 0,
@@ -48,9 +48,9 @@ impl<'s> Engine<'s> {
 
         // Move cursor to top-left position
         self.text_commands.push(TextCommand::Move(
-            self.style.margins[0],
-            self.style.paper_size[1] - self.style.margins[1])
-        );
+            self.style.margin_left,
+            self.style.height - self.style.margin_top
+        ));
 
         // Set the current font
         self.text_commands.push(TextCommand::SetFont(0, self.style.font_size));
@@ -70,7 +70,8 @@ impl<'s> Engine<'s> {
 
         // Create a page from the contents.
         let page = Page {
-            size: self.style.paper_size,
+            width: self.style.width,
+            height: self.style.height,
             text: vec![Text {
                 commands: self.text_commands,
             }],
@@ -83,15 +84,10 @@ impl<'s> Engine<'s> {
     }
 
     fn write_word(&mut self, word: &str) {
-        let max_width = self.style.paper_size[0] - 2 * self.style.margins[0];
-
         let font = &self.fonts[self.active_font];
-        let width = word.chars()
-            .map(|c| font.widths[font.map(c) as usize] * self.style.font_size)
-            .sum();
-
 
-        if self.current_width + width > max_width {
+        let width = self.width(word);
+        if self.would_overflow(width) {
             let vertical_move = - self.style.font_size
                 * self.style.line_spacing
                 * font.metrics.ascender;
@@ -107,10 +103,29 @@ impl<'s> Engine<'s> {
     }
 
     fn write_space(&mut self) {
-        if !self.current_line.is_empty() {
-            self.write_word(" ");
+        let space_width = self.width(" ");
+
+        if !self.would_overflow(space_width) && !self.current_line.is_empty() {
+            self.text_commands.push(TextCommand::Text(" ".to_owned()));
+            self.current_line.push_str(" ");
+            self.current_width += space_width;
         }
     }
+
+    fn width(&self, word: &str) -> Size {
+        let font = &self.fonts[self.active_font];
+        word.chars()
+            .map(|c| font.widths[font.map(c) as usize] * self.style.font_size)
+            .sum()
+    }
+
+    fn would_overflow(&self, width: Size) -> bool {
+        let max_width = self.style.width
+            - self.style.margin_left
+            - self.style.margin_right;
+
+        self.current_width + width > max_width
+    }
 }
 
 /// Result type used for parsing.
diff --git a/src/lib.rs b/src/lib.rs
index deb5b066..ae12bf8b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -37,20 +37,32 @@ use std::error;
 use std::fmt;
 use std::io::Write;
 use crate::syntax::SyntaxTree;
-use crate::doc::Document;
+use crate::doc::{Document, Style};
 
 
 /// Emits various compiled intermediates from source code.
 pub struct Compiler<'s> {
     /// The source code of the document.
     source: &'s str,
+    /// Style for typesetting.
+    style: Style,
 }
 
 impl<'s> Compiler<'s> {
     /// Create a new compiler from a document.
     #[inline]
     pub fn new(source: &'s str) -> Compiler<'s> {
-        Compiler { source }
+        Compiler {
+            source,
+            style: Style::default(),
+        }
+    }
+
+    /// Set the default style for typesetting.
+    #[inline]
+    pub fn style(&mut self, style: Style) -> &mut Self {
+        self.style = style;
+        self
     }
 
     /// Return an iterator over the tokens of the document.
@@ -69,7 +81,7 @@ impl<'s> Compiler<'s> {
     #[inline]
     pub fn typeset(&self) -> Result<Document, Error> {
         let tree = self.parse()?;
-        Engine::new(&tree).typeset().map_err(Into::into)
+        Engine::new(&tree, self.style.clone()).typeset().map_err(Into::into)
     }
 
     /// Write the document as a _PDF_, returning how many bytes were written.
@@ -159,7 +171,7 @@ mod test {
     }
 
     #[test]
-    fn long() {
+    fn long_styled() {
         test("wikipedia", r#"
             Typesetting is the composition of text by means of arranging physical types or the
             digital equivalents. Stored letters and other symbols (called sorts in mechanical
diff --git a/src/pdf.rs b/src/pdf.rs
index d5d3b081..e5a2cf6b 100644
--- a/src/pdf.rs
+++ b/src/pdf.rs
@@ -122,11 +122,11 @@ impl<'a, W: Write> PdfCreator<'a, W> {
         // The page objects
         let mut id = self.offsets.pages.0;
         for page in &self.doc.pages {
-            let width = page.size[0].to_points();
-            let height = page.size[1].to_points();
-
             self.writer.write_obj(id, Page::new(self.offsets.page_tree)
-                .media_box(Rect::new(0.0, 0.0, width, height))
+                .media_box(Rect::new(
+                    0.0, 0.0,
+                    page.width.to_points(), page.height.to_points())
+                )
                 .contents(self.offsets.contents.0 ..= self.offsets.contents.1)
             )?;