Fix top-left text alignment 📐

8 files changed, 70 insertions, 55 deletions

diff --git a/src/doc.rs b/src/doc.rs
index f08332f6..0b4db73e 100644
--- a/src/doc.rs
+++ b/src/doc.rs
@@ -20,19 +20,17 @@ pub struct Page {
     pub width: Size,
     /// The height of the page.
     pub height: Size,
-    /// Text actions specifying how to draw text content on the page.
-    pub actions: Vec<TextAction>,
+    /// Layouting actions specifying how to draw content on the page.
+    pub actions: Vec<LayoutAction>,
 }
 
-/// A text layouting action.
+/// A layouting action.
 #[derive(Debug, Clone)]
-pub enum TextAction {
+pub enum LayoutAction {
     /// Move to an absolute position.
     MoveAbsolute(Size2D),
-    /// Move from the _start_ of the current line by an (x, y) offset.
-    MoveNewline(Size2D),
-    /// Write text starting at the current position.
-    WriteText(String),
     /// Set the font by index and font size.
     SetFont(usize, f32),
+    /// Write text starting at the current position.
+    WriteText(String),
 }
diff --git a/src/export/pdf.rs b/src/export/pdf.rs
index 1c0d52b0..a09f3b0c 100644
--- a/src/export/pdf.rs
+++ b/src/export/pdf.rs
@@ -8,9 +8,9 @@ use pdf::doc::{Catalog, PageTree, Page, Resource, Text};
 use pdf::font::{Type0Font, CIDFont, CIDFontType, CIDSystemInfo, FontDescriptor, FontFlags};
 use pdf::font::{GlyphUnit, CMap, CMapEncoding, WidthRecord, FontStream};
 
-use crate::doc::{Document, Page as DocPage, TextAction};
+use crate::doc::{Document, Page as DocPage, LayoutAction};
 use crate::font::{Font, FontError};
-use crate::size::Size;
+use crate::size::{Size, Size2D};
 
 
 /// Exports documents into _PDFs_.
@@ -72,8 +72,8 @@ impl<'d, W: Write> PdfEngine<'d, W> {
             for page in &doc.pages {
                 for action in &page.actions {
                     match action {
-                        TextAction::WriteText(string) => chars[font].extend(string.chars()),
-                        TextAction::SetFont(id, _) => font = *id,
+                        LayoutAction::WriteText(string) => chars[font].extend(string.chars()),
+                        LayoutAction::SetFont(id, _) => font = *id,
                         _ => {},
                     }
                 }
@@ -123,7 +123,7 @@ impl<'d, W: Write> PdfEngine<'d, W> {
         // The page objects
         for (id, page) in ids(self.offsets.pages).zip(&self.doc.pages) {
             self.writer.write_obj(id, Page::new(self.offsets.page_tree)
-                .media_box(Rect::new(0.0, 0.0, page.width.to_points(), page.height.to_points()))
+                .media_box(Rect::new(0.0, 0.0, page.width.to_pt(), page.height.to_pt()))
                 .contents(ids(self.offsets.contents))
             )?;
         }
@@ -141,23 +141,40 @@ impl<'d, W: Write> PdfEngine<'d, W> {
 
     /// Write the content of a page.
     fn write_page(&mut self, id: u32, page: &DocPage) -> PdfResult<()> {
-        let mut font = 0;
-        let mut text = Text::new();
+        // The currently used font.
+        let mut active_font = (std::usize::MAX, 0.0);
+
+        // The last set position and font, these get flushed when content is written.
+        let mut next_pos = Some(Size2D::zero());
+        let mut next_font = None;
 
-        text.tm(1.0, 0.0, 0.0, 1.0, 0.0, page.height.to_points());
+        // The output text.
+        let mut text = Text::new();
 
         for action in &page.actions {
             match action {
-                TextAction::MoveAbsolute(pos) => {
-                    let x = pos.x.to_points();
-                    let y = (page.height - pos.y).to_points();
-                    text.tm(1.0, 0.0, 0.0, 1.0, x, y);
-                },
-                TextAction::MoveNewline(pos) => { text.td(pos.x.to_points(), -pos.y.to_points()); },
-                TextAction::WriteText(string) => { text.tj(self.fonts[font].encode(&string)); },
-                TextAction::SetFont(id, size) => {
-                    font = *id;
-                    text.tf(*id as u32 + 1, *size);
+                LayoutAction::MoveAbsolute(pos) => next_pos = Some(*pos),
+                LayoutAction::SetFont(id, size) => next_font = Some((*id, *size)),
+                LayoutAction::WriteText(string) => {
+                    // Flush the font if it is different from the current.
+                    if let Some((id, size)) = next_font {
+                        if (id, size) != active_font {
+                            text.tf(id as u32 + 1, size);
+                            active_font = (id, size);
+                            next_font = None;
+                        }
+                    }
+
+                    // Flush the position.
+                    if let Some(pos) = next_pos {
+                        let x = pos.x.to_pt();
+                        let y = (page.height - pos.y - Size::pt(active_font.1)).to_pt();
+                        text.tm(1.0, 0.0, 0.0, 1.0, x, y);
+                        next_pos = None;
+                    }
+
+                    // Write the text.
+                    text.tj(self.fonts[active_font.0].encode(&string));
                 },
             }
         }
@@ -249,7 +266,7 @@ impl PdfFont {
     fn new(font: &Font, chars: &HashSet<char>) -> PdfResult<PdfFont> {
         /// Convert a size into a _PDF_ glyph unit.
         fn size_to_glyph_unit(size: Size) -> GlyphUnit {
-            (1000.0 * size.to_points()).round() as GlyphUnit
+            (1000.0 * size.to_pt()).round() as GlyphUnit
         }
 
         // Subset the font using the selected characters.
diff --git a/src/font.rs b/src/font.rs
index 9b13ed32..d11fe75c 100644
--- a/src/font.rs
+++ b/src/font.rs
@@ -60,7 +60,7 @@ impl Font {
 
         // Create a conversion function between font units and sizes.
         let font_unit_ratio = 1.0 / (head.units_per_em as f32);
-        let font_unit_to_size = |x| Size::points(font_unit_ratio * x as f32);
+        let font_unit_to_size = |x| Size::pt(font_unit_ratio * x as f32);
 
         // Find out the name of the font.
         let font_name = name.get_decoded(NameEntry::PostScriptName)
diff --git a/src/layout/boxed.rs b/src/layout/boxed.rs
index e712f650..15af278a 100644
--- a/src/layout/boxed.rs
+++ b/src/layout/boxed.rs
@@ -1,6 +1,6 @@
 //! Block-style layouting of boxes.
 
-use crate::doc::{Document, Page, TextAction};
+use crate::doc::{Document, Page, LayoutAction};
 use crate::font::Font;
 use crate::size::{Size, Size2D};
 use super::{ActionList, LayoutSpace, LayoutResult, LayoutError};
@@ -12,7 +12,7 @@ pub struct BoxLayout {
     /// The size of the box.
     pub dimensions: Size2D,
     /// The actions composing this layout.
-    pub actions: Vec<TextAction>,
+    pub actions: Vec<LayoutAction>,
 }
 
 impl BoxLayout {
@@ -90,7 +90,7 @@ impl BoxLayouter {
     pub fn add_box_absolute(&mut self, position: Size2D, layout: BoxLayout) {
         // Move all actions into this layout and translate absolute positions.
         self.actions.reset_origin();
-        self.actions.add(TextAction::MoveAbsolute(position));
+        self.actions.add(LayoutAction::MoveAbsolute(position));
         self.actions.set_origin(position);
         self.actions.extend(layout.actions);
     }
diff --git a/src/layout/flex.rs b/src/layout/flex.rs
index f966eae2..730b876e 100644
--- a/src/layout/flex.rs
+++ b/src/layout/flex.rs
@@ -1,6 +1,6 @@
 //! Flexible and lazy layouting of boxes.
 
-use crate::doc::TextAction;
+use crate::doc::LayoutAction;
 use crate::size::{Size, Size2D};
 use super::{BoxLayout, ActionList, LayoutSpace, LayoutResult, LayoutError};
 
@@ -157,7 +157,7 @@ impl FlexFinisher {
     fn append(&mut self, layout: BoxLayout) {
         // Move all actions into this layout and translate absolute positions.
         self.actions.reset_origin();
-        self.actions.add(TextAction::MoveAbsolute(self.cursor));
+        self.actions.add(LayoutAction::MoveAbsolute(self.cursor));
         self.actions.set_origin(self.cursor);
         self.actions.extend(layout.actions);
 
diff --git a/src/layout/mod.rs b/src/layout/mod.rs
index 40948a13..b678ab2b 100644
--- a/src/layout/mod.rs
+++ b/src/layout/mod.rs
@@ -1,6 +1,6 @@
 //! The layouting engine.
 
-use crate::doc::TextAction;
+use crate::doc::LayoutAction;
 use crate::font::{FontLoader, FontError};
 use crate::size::{Size, Size2D, SizeBox};
 use crate::syntax::{SyntaxTree, Node};
@@ -86,7 +86,7 @@ impl<'a, 'p> Layouter<'a, 'p> {
                 padding: SizeBox::zero(),
                 shrink_to_fit: true,
             },
-            flex_spacing: (ctx.style.line_spacing - 1.0) * Size::points(ctx.style.font_size),
+            flex_spacing: (ctx.style.line_spacing - 1.0) * Size::pt(ctx.style.font_size),
         };
 
         // The mutable context for layouting single pieces of text.
@@ -192,7 +192,7 @@ impl<'a, 'p> Layouter<'a, 'p> {
 
     /// Add the spacing between two paragraphs.
     fn add_paragraph_spacing(&mut self) -> LayoutResult<()> {
-        let size = Size::points(self.text_ctx.style.font_size)
+        let size = Size::pt(self.text_ctx.style.font_size)
             * (self.text_ctx.style.line_spacing * self.text_ctx.style.paragraph_spacing - 1.0);
         self.box_layouter.add_space(size)
     }
@@ -201,7 +201,7 @@ impl<'a, 'p> Layouter<'a, 'p> {
 /// Manipulates and optimizes a list of actions.
 #[derive(Debug, Clone)]
 pub struct ActionList {
-    actions: Vec<TextAction>,
+    actions: Vec<LayoutAction>,
     origin: Size2D,
     active_font: (usize, f32),
 }
@@ -218,8 +218,8 @@ impl ActionList {
 
     /// Add an action to the list if it is not useless
     /// (like changing to a font that is already active).
-    pub fn add(&mut self, action: TextAction) {
-        use TextAction::*;
+    pub fn add(&mut self, action: LayoutAction) {
+        use LayoutAction::*;
         match action {
             MoveAbsolute(pos) => self.actions.push(MoveAbsolute(self.origin + pos)),
             SetFont(index, size) => if (index, size) != self.active_font {
@@ -231,7 +231,7 @@ impl ActionList {
     }
 
     /// Add a series of actions.
-    pub fn extend<I>(&mut self, actions: I) where I: IntoIterator<Item=TextAction> {
+    pub fn extend<I>(&mut self, actions: I) where I: IntoIterator<Item=LayoutAction> {
         for action in actions.into_iter() {
             self.add(action);
         }
@@ -254,7 +254,7 @@ impl ActionList {
     }
 
     /// Return the list of actions as a vector.
-    pub fn into_vec(self) -> Vec<TextAction> {
+    pub fn into_vec(self) -> Vec<LayoutAction> {
         self.actions
     }
 }
diff --git a/src/layout/text.rs b/src/layout/text.rs
index 8aa76c4c..0a0241a0 100644
--- a/src/layout/text.rs
+++ b/src/layout/text.rs
@@ -1,6 +1,6 @@
 //! Layouting of text into boxes.
 
-use crate::doc::TextAction;
+use crate::doc::LayoutAction;
 use crate::font::FontQuery;
 use crate::size::{Size, Size2D};
 use super::*;
@@ -39,11 +39,11 @@ pub fn layout(text: &str, ctx: &TextContext) -> LayoutResult<BoxLayout> {
         // Change the font if necessary.
         if active_font != index {
             if !buffer.is_empty() {
-                actions.push(TextAction::WriteText(buffer));
+                actions.push(LayoutAction::WriteText(buffer));
                 buffer = String::new();
             }
 
-            actions.push(TextAction::SetFont(index, ctx.style.font_size));
+            actions.push(LayoutAction::SetFont(index, ctx.style.font_size));
             active_font = index;
         }
 
@@ -52,11 +52,11 @@ pub fn layout(text: &str, ctx: &TextContext) -> LayoutResult<BoxLayout> {
 
     // Write the remaining characters.
     if !buffer.is_empty() {
-        actions.push(TextAction::WriteText(buffer));
+        actions.push(LayoutAction::WriteText(buffer));
     }
 
     Ok(BoxLayout {
-        dimensions: Size2D::new(width, Size::points(ctx.style.font_size)),
+        dimensions: Size2D::new(width, Size::pt(ctx.style.font_size)),
         actions,
     })
 }
diff --git a/src/size.rs b/src/size.rs
index e1f54a4f..674abdb5 100644
--- a/src/size.rs
+++ b/src/size.rs
@@ -42,11 +42,7 @@ impl Size {
 
     /// Create a size from an amount of points.
     #[inline]
-    pub fn points(points: f32) -> Size { Size { points } }
-
-    /// Create a size from an amount of inches.
-    #[inline]
-    pub fn inches(inches: f32) -> Size { Size { points: 72.0 * inches } }
+    pub fn pt(points: f32) -> Size { Size { points } }
 
     /// Create a size from an amount of millimeters.
     #[inline]
@@ -56,13 +52,13 @@ impl Size {
     #[inline]
     pub fn cm(cm: f32) -> Size { Size { points: 28.3465 * cm } }
 
-    /// Convert this size into points.
+    /// Create a size from an amount of inches.
     #[inline]
-    pub fn to_points(&self) -> f32 { self.points }
+    pub fn inches(inches: f32) -> Size { Size { points: 72.0 * inches } }
 
-    /// Convert this size into inches.
+    /// Convert this size into points.
     #[inline]
-    pub fn to_inches(&self) -> f32 { self.points * 0.0138889 }
+    pub fn to_pt(&self) -> f32 { self.points }
 
     /// Convert this size into millimeters.
     #[inline]
@@ -71,6 +67,10 @@ impl Size {
     /// Convert this size into centimeters.
     #[inline]
     pub fn to_cm(&self) -> f32 { self.points * 0.0352778 }
+
+    /// Convert this size into inches.
+    #[inline]
+    pub fn to_inches(&self) -> f32 { self.points * 0.0138889 }
 }
 
 impl Size2D {