Export images in PDF 🖼

6 files changed, 248 insertions, 186 deletions

diff --git a/bench/src/bench.rs b/bench/src/bench.rs
index e004c5ce..bc13ed01 100644
--- a/bench/src/bench.rs
+++ b/bench/src/bench.rs
@@ -11,7 +11,7 @@ use typst::layout::layout;
 use typst::parse::parse;
 use typst::typeset;
 
-const FONT_DIR: &str = "fonts";
+const FONT_DIR: &str = "../fonts";
 const COMA: &str = include_str!("../../tests/typ/coma.typ");
 
 fn benchmarks(c: &mut Criterion) {
diff --git a/src/export/pdf.rs b/src/export/pdf.rs
index c5d8d871..af3ca0a6 100644
--- a/src/export/pdf.rs
+++ b/src/export/pdf.rs
@@ -3,8 +3,10 @@
 use std::collections::HashMap;
 
 use fontdock::FaceId;
+use image::RgbImage;
 use pdf_writer::{
-    CIDFontType, FontFlags, Name, PdfWriter, Rect, Ref, Str, SystemInfo, TextStream,
+    CidFontType, ColorSpace, Content, FontFlags, Name, PdfWriter, Rect, Ref, Str,
+    SystemInfo, UnicodeCmap,
 };
 use ttf_parser::{name_id, GlyphId};
 
@@ -31,136 +33,167 @@ struct PdfExporter<'a> {
     /// which objects up-front to correctly declare the document catalogue, page
     /// tree and so on. These offsets are computed in the beginning and stored
     /// here.
-    offsets: Offsets,
-    // Font remapping, for more information see `remap_fonts`.
-    to_pdf: HashMap<FaceId, usize>,
-    to_layout: Vec<FaceId>,
+    refs: Refs,
+    /// We assign a new PDF-internal index to each used face.
+    /// There are two mappings:
+    /// Forwards from the old face ids to the new pdf indices.
+    fonts_to_pdf: HashMap<FaceId, usize>,
+    /// Backwards from the pdf indices to the old face ids.
+    fonts_to_layout: Vec<FaceId>,
+    /// The already visited images.
+    images: Vec<&'a RgbImage>,
+    /// The total number of images.
+    image_count: usize,
 }
 
-struct Offsets {
-    catalog: Ref,
-    page_tree: Ref,
-    pages: (i32, i32),
-    contents: (i32, i32),
-    fonts: (i32, i32),
-}
-
-const NUM_OBJECTS_PER_FONT: i32 = 5;
-
 impl<'a> PdfExporter<'a> {
     fn new(layouts: &'a [BoxLayout], loader: &'a FontLoader) -> Self {
-        let (to_pdf, to_fontdock) = remap_fonts(layouts);
-        let offsets = calculate_offsets(layouts.len(), to_pdf.len());
         let mut writer = PdfWriter::new(1, 7);
         writer.set_indent(2);
 
+        let mut fonts_to_pdf = HashMap::new();
+        let mut fonts_to_layout = vec![];
+        let mut image_count = 0;
+
+        for layout in layouts {
+            for (_, element) in &layout.elements {
+                match element {
+                    LayoutElement::Text(shaped) => {
+                        fonts_to_pdf.entry(shaped.face).or_insert_with(|| {
+                            let next_id = fonts_to_layout.len();
+                            fonts_to_layout.push(shaped.face);
+                            next_id
+                        });
+                    }
+                    LayoutElement::Image(_) => image_count += 1,
+                }
+            }
+        }
+
+        let refs = Refs::new(layouts.len(), fonts_to_pdf.len(), image_count);
+
         Self {
             writer,
             layouts,
-            offsets,
-            to_pdf,
-            to_layout: to_fontdock,
             loader,
+            refs,
+            fonts_to_pdf,
+            fonts_to_layout,
+            images: vec![],
+            image_count,
         }
     }
 
     fn write(mut self) -> Vec<u8> {
-        self.write_preface();
+        self.write_structure();
         self.write_pages();
         self.write_fonts();
-        self.writer.end(self.offsets.catalog)
+        self.write_images();
+        self.writer.finish(self.refs.catalog)
     }
 
-    fn write_preface(&mut self) {
+    fn write_structure(&mut self) {
         // The document catalog.
-        self.writer
-            .catalog(self.offsets.catalog)
-            .pages(self.offsets.page_tree);
+        self.writer.catalog(self.refs.catalog).pages(self.refs.page_tree);
 
         // The root page tree.
-        {
-            let mut pages = self.writer.pages(self.offsets.page_tree);
-            pages.kids(ids(self.offsets.pages));
-
-            let mut resources = pages.resources();
-            let mut fonts = resources.fonts();
-            for i in 0 .. self.to_pdf.len() {
-                let mut buf = itoa::Buffer::new();
-                fonts.pair(
-                    Name(buf.format(1 + i as i32).as_bytes()),
-                    Ref::new(self.offsets.fonts.0 + NUM_OBJECTS_PER_FONT * i as i32),
-                );
-            }
+        let mut pages = self.writer.pages(self.refs.page_tree);
+        pages.kids(self.refs.pages());
+
+        let mut resources = pages.resources();
+        let mut fonts = resources.fonts();
+        for (refs, f) in self.refs.fonts().zip(0 .. self.fonts_to_pdf.len()) {
+            let name = format!("F{}", f);
+            fonts.pair(Name(name.as_bytes()), refs.type0_font);
         }
 
+        drop(fonts);
+
+        let mut images = resources.x_objects();
+        for (id, im) in self.refs.images().zip(0 .. self.image_count) {
+            let name = format!("Im{}", im);
+            images.pair(Name(name.as_bytes()), id);
+        }
+
+        drop(images);
+        drop(resources);
+        drop(pages);
+
         // The page objects (non-root nodes in the page tree).
-        for ((page_id, content_id), page) in ids(self.offsets.pages)
-            .zip(ids(self.offsets.contents))
-            .zip(self.layouts)
+        for ((page_id, content_id), page) in
+            self.refs.pages().zip(self.refs.contents()).zip(self.layouts)
         {
-            let rect = Rect::new(
-                0.0,
-                0.0,
-                page.size.width.to_pt() as f32,
-                page.size.height.to_pt() as f32,
-            );
-
             self.writer
                 .page(page_id)
-                .parent(self.offsets.page_tree)
-                .media_box(rect)
+                .parent(self.refs.page_tree)
+                .media_box(Rect::new(
+                    0.0,
+                    0.0,
+                    page.size.width.to_pt() as f32,
+                    page.size.height.to_pt() as f32,
+                ))
                 .contents(content_id);
         }
     }
 
     fn write_pages(&mut self) {
-        for (id, page) in ids(self.offsets.contents).zip(self.layouts) {
+        for (id, page) in self.refs.contents().zip(self.layouts) {
             self.write_page(id, &page);
         }
     }
 
-    fn write_page(&mut self, id: Ref, page: &BoxLayout) {
-        let mut text = TextStream::new();
+    fn write_page(&mut self, id: Ref, page: &'a BoxLayout) {
+        let mut content = Content::new();
 
-        // Font switching actions are only written when the face used for
-        // shaped text changes. Hence, we need to remember the active face.
+        // We only write font switching actions when the used face changes. To
+        // do that, we need to remember the active face.
         let mut face = FaceId::MAX;
         let mut size = Length::ZERO;
 
+        let mut text = content.text();
         for (pos, element) in &page.elements {
-            match element {
-                LayoutElement::Text(shaped) => {
-                    // Check if we need to issue a font switching action.
-                    if shaped.face != face || shaped.font_size != size {
-                        face = shaped.face;
-                        size = shaped.font_size;
-
-                        let mut buf = itoa::Buffer::new();
-                        text = text.tf(
-                            Name(buf.format(1 + self.to_pdf[&shaped.face]).as_bytes()),
-                            size.to_pt() as f32,
-                        );
-                    }
+            if let LayoutElement::Text(shaped) = element {
+                // Check if we need to issue a font switching action.
+                if shaped.face != face || shaped.font_size != size {
+                    face = shaped.face;
+                    size = shaped.font_size;
 
-                    let x = pos.x.to_pt();
-                    let y = (page.size.height - pos.y - size).to_pt();
-                    text = text.tm(1.0, 0.0, 0.0, 1.0, x as f32, y as f32);
-                    text = text.tj(&shaped.encode_glyphs_be());
+                    let name = format!("F{}", self.fonts_to_pdf[&shaped.face]);
+                    text.font(Name(name.as_bytes()), size.to_pt() as f32);
                 }
 
-                LayoutElement::Image(_image) => {
-                    // TODO: Write image.
-                }
+                let x = pos.x.to_pt() as f32;
+                let y = (page.size.height - pos.y - size).to_pt() as f32;
+                text.matrix(1.0, 0.0, 0.0, 1.0, x, y);
+                text.show(&shaped.encode_glyphs_be());
             }
         }
 
-        self.writer.stream(id, &text.end());
+        drop(text);
+
+        for (pos, element) in &page.elements {
+            if let LayoutElement::Image(image) = element {
+                let name = format!("Im{}", self.images.len());
+                let size = image.size;
+                let x = pos.x.to_pt() as f32;
+                let y = (page.size.height - pos.y - size.height).to_pt() as f32;
+                let w = size.width.to_pt() as f32;
+                let h = size.height.to_pt() as f32;
+
+                content.save_state();
+                content.matrix(w, 0.0, 0.0, h, x, y);
+                content.x_object(Name(name.as_bytes()));
+                content.restore_state();
+
+                self.images.push(&image.buf);
+            }
+        }
+
+        self.writer.stream(id, &content.finish());
     }
 
     fn write_fonts(&mut self) {
-        let mut id = self.offsets.fonts.0;
-
-        for &face_id in &self.to_layout {
+        for (refs, &face_id) in self.refs.fonts().zip(&self.fonts_to_layout) {
             let owned_face = self.loader.get_loaded(face_id);
             let face = owned_face.get();
 
@@ -169,151 +202,179 @@ impl<'a> PdfExporter<'a> {
                 .find(|entry| {
                     entry.name_id() == name_id::POST_SCRIPT_NAME && entry.is_unicode()
                 })
-                .map(|entry| entry.to_string())
-                .flatten()
+                .and_then(|entry| entry.to_string())
                 .unwrap_or_else(|| "unknown".to_string());
 
             let base_font = format!("ABCDEF+{}", name);
             let base_font = Name(base_font.as_bytes());
+            let cmap_name = Name(b"Custom");
             let system_info = SystemInfo {
                 registry: Str(b"Adobe"),
                 ordering: Str(b"Identity"),
                 supplement: 0,
             };
 
-            let units_per_em = face.units_per_em().unwrap_or(1000) as f32;
-            let ratio = 1.0 / units_per_em;
-            let to_glyph_unit = |font_unit: f32| (1000.0 * ratio * font_unit).round();
-
-            let global_bbox = face.global_bounding_box();
-            let bbox = Rect::new(
-                to_glyph_unit(global_bbox.x_min as f32),
-                to_glyph_unit(global_bbox.y_min as f32),
-                to_glyph_unit(global_bbox.x_max as f32),
-                to_glyph_unit(global_bbox.y_max as f32),
-            );
-
-            let monospace = face.is_monospaced();
-            let italic = face.is_italic();
-            let italic_angle = face.italic_angle().unwrap_or(0.0);
-            let ascender = face.typographic_ascender().unwrap_or(0);
-            let descender = face.typographic_descender().unwrap_or(0);
-            let cap_height = face.capital_height().unwrap_or(ascender);
-            let stem_v = 10.0 + 0.244 * (face.weight().to_number() as f32 - 50.0);
-
             let mut flags = FontFlags::empty();
             flags.set(FontFlags::SERIF, name.contains("Serif"));
-            flags.set(FontFlags::FIXED_PITCH, monospace);
-            flags.set(FontFlags::ITALIC, italic);
+            flags.set(FontFlags::FIXED_PITCH, face.is_monospaced());
+            flags.set(FontFlags::ITALIC, face.is_italic());
             flags.insert(FontFlags::SYMBOLIC);
             flags.insert(FontFlags::SMALL_CAP);
 
-            let num_glyphs = face.number_of_glyphs();
-            let widths = (0 .. num_glyphs).map(|g| {
-                to_glyph_unit(face.glyph_hor_advance(GlyphId(g)).unwrap_or(0) as f32)
-            });
-
-            let mut mapping = vec![];
-            for subtable in face.character_mapping_subtables() {
-                subtable.codepoints(|n| {
-                    if let Some(c) = std::char::from_u32(n) {
-                        if let Some(g) = face.glyph_index(c) {
-                            mapping.push((g.0, c));
-                        }
-                    }
-                })
-            }
+            // Convert from OpenType font units to PDF glyph units.
+            let em_per_unit = 1.0 / face.units_per_em().unwrap_or(1000) as f32;
+            let convert = |font_unit: f32| (1000.0 * em_per_unit * font_unit).round();
+            let convert_i16 = |font_unit: i16| convert(font_unit as f32);
+            let convert_u16 = |font_unit: u16| convert(font_unit as f32);
 
-            let type0_font_id = Ref::new(id);
-            let cid_font_id = Ref::new(id + 1);
-            let font_descriptor_id = Ref::new(id + 2);
-            let cmap_id = Ref::new(id + 3);
-            let data_id = Ref::new(id + 4);
+            let global_bbox = face.global_bounding_box();
+            let bbox = Rect::new(
+                convert_i16(global_bbox.x_min),
+                convert_i16(global_bbox.y_min),
+                convert_i16(global_bbox.x_max),
+                convert_i16(global_bbox.y_max),
+            );
+
+            let italic_angle = face.italic_angle().unwrap_or(0.0);
+            let ascender = convert_i16(face.typographic_ascender().unwrap_or(0));
+            let descender = convert_i16(face.typographic_descender().unwrap_or(0));
+            let cap_height = face.capital_height().map(convert_i16);
+            let stem_v = 10.0 + 0.244 * (f32::from(face.weight().to_number()) - 50.0);
 
             // Write the base font object referencing the CID font.
             self.writer
-                .type0_font(type0_font_id)
+                .type0_font(refs.type0_font)
                 .base_font(base_font)
                 .encoding_predefined(Name(b"Identity-H"))
-                .descendant_font(cid_font_id)
-                .to_unicode(cmap_id);
+                .descendant_font(refs.cid_font)
+                .to_unicode(refs.cmap);
 
             // Write the CID font referencing the font descriptor.
             self.writer
-                .cid_font(cid_font_id, CIDFontType::Type2)
+                .cid_font(refs.cid_font, CidFontType::Type2)
                 .base_font(base_font)
                 .system_info(system_info)
-                .font_descriptor(font_descriptor_id)
+                .font_descriptor(refs.font_descriptor)
                 .widths()
-                .individual(0, widths);
+                .individual(0, {
+                    let num_glyphs = face.number_of_glyphs();
+                    (0 .. num_glyphs).map(|g| {
+                        let advance = face.glyph_hor_advance(GlyphId(g));
+                        convert_u16(advance.unwrap_or(0))
+                    })
+                });
 
             // Write the font descriptor (contains metrics about the font).
             self.writer
-                .font_descriptor(font_descriptor_id)
+                .font_descriptor(refs.font_descriptor)
                 .font_name(base_font)
                 .font_flags(flags)
                 .font_bbox(bbox)
                 .italic_angle(italic_angle)
-                .ascent(to_glyph_unit(ascender as f32))
-                .descent(to_glyph_unit(descender as f32))
-                .cap_height(to_glyph_unit(cap_height as f32))
+                .ascent(ascender)
+                .descent(descender)
+                .cap_height(cap_height.unwrap_or(ascender))
                 .stem_v(stem_v)
-                .font_file2(data_id);
+                .font_file2(refs.data);
 
-            // Write the CMap, which maps glyph ids back to unicode codepoints
-            // to enable copying out of the PDF.
-            self.writer.cmap(cmap_id, Name(b"Custom"), system_info, mapping);
+            // Write the to-unicode character map, which maps glyph ids back to
+            // unicode codepoints to enable copying out of the PDF.
+            self.writer
+                .cmap_stream(refs.cmap, &{
+                    let mut cmap = UnicodeCmap::new(cmap_name, system_info);
+                    for subtable in face.character_mapping_subtables() {
+                        subtable.codepoints(|n| {
+                            if let Some(c) = std::char::from_u32(n) {
+                                if let Some(g) = face.glyph_index(c) {
+                                    cmap.pair(g.0, c);
+                                }
+                            }
+                        })
+                    }
+                    cmap.finish()
+                })
+                .name(cmap_name)
+                .system_info(system_info);
 
             // Write the face's bytes.
-            self.writer.stream(data_id, owned_face.data());
+            self.writer.stream(refs.data, owned_face.data());
+        }
+    }
 
-            id += NUM_OBJECTS_PER_FONT;
+    fn write_images(&mut self) {
+        for (id, image) in self.refs.images().zip(&self.images) {
+            self.writer
+                .image_stream(id, &image.as_raw())
+                .width(image.width() as i32)
+                .height(image.height() as i32)
+                .color_space(ColorSpace::DeviceRGB)
+                .bits_per_component(8);
         }
     }
 }
 
-/// Assigns a new PDF-internal index to each used face and returns two mappings:
-/// - Forwards from the old face ids to the new pdf indices (hash map)
-/// - Backwards from the pdf indices to the old face ids (vec)
-fn remap_fonts(layouts: &[BoxLayout]) -> (HashMap<FaceId, usize>, Vec<FaceId>) {
-    let mut to_pdf = HashMap::new();
-    let mut to_layout = vec![];
-
-    // We want to find out which font faces are used at all. To do that, look at
-    // each text element to find out which face is uses.
-    for layout in layouts {
-        for (_, element) in &layout.elements {
-            if let LayoutElement::Text(shaped) = element {
-                to_pdf.entry(shaped.face).or_insert_with(|| {
-                    let next_id = to_layout.len();
-                    to_layout.push(shaped.face);
-                    next_id
-                });
-            }
+struct Refs {
+    catalog: Ref,
+    page_tree: Ref,
+    pages_start: i32,
+    contents_start: i32,
+    fonts_start: i32,
+    images_start: i32,
+    end: i32,
+}
+
+struct FontRefs {
+    type0_font: Ref,
+    cid_font: Ref,
+    font_descriptor: Ref,
+    cmap: Ref,
+    data: Ref,
+}
+
+impl Refs {
+    const OBJECTS_PER_FONT: usize = 5;
+
+    fn new(layouts: usize, fonts: usize, images: usize) -> Self {
+        let catalog = 1;
+        let page_tree = catalog + 1;
+        let pages_start = page_tree + 1;
+        let contents_start = pages_start + layouts as i32;
+        let fonts_start = contents_start + layouts as i32;
+        let images_start = fonts_start + (Self::OBJECTS_PER_FONT * fonts) as i32;
+        let end = images_start + images as i32;
+
+        Self {
+            catalog: Ref::new(catalog),
+            page_tree: Ref::new(page_tree),
+            pages_start,
+            contents_start,
+            fonts_start,
+            images_start,
+            end,
         }
     }
 
-    (to_pdf, to_layout)
-}
+    fn pages(&self) -> impl Iterator<Item = Ref> {
+        (self.pages_start .. self.contents_start).map(Ref::new)
+    }
 
-/// We need to know in advance which ids to use for which objects to
-/// cross-reference them. Therefore, we calculate the indices in the beginning.
-fn calculate_offsets(layout_count: usize, font_count: usize) -> Offsets {
-    let catalog = 1;
-    let page_tree = catalog + 1;
-    let pages = (page_tree + 1, page_tree + layout_count as i32);
-    let contents = (pages.1 + 1, pages.1 + layout_count as i32);
-    let font_offsets = (contents.1 + 1, contents.1 + 5 * font_count as i32);
-
-    Offsets {
-        catalog: Ref::new(catalog),
-        page_tree: Ref::new(page_tree),
-        pages,
-        contents,
-        fonts: font_offsets,
+    fn contents(&self) -> impl Iterator<Item = Ref> {
+        (self.contents_start .. self.images_start).map(Ref::new)
+    }
+
+    fn fonts(&self) -> impl Iterator<Item = FontRefs> {
+        (self.fonts_start .. self.images_start)
+            .step_by(Self::OBJECTS_PER_FONT)
+            .map(|id| FontRefs {
+                type0_font: Ref::new(id),
+                cid_font: Ref::new(id + 1),
+                font_descriptor: Ref::new(id + 2),
+                cmap: Ref::new(id + 3),
+                data: Ref::new(id + 4),
+            })
     }
-}
 
-fn ids((start, end): (i32, i32)) -> impl Iterator<Item = Ref> {
-    (start ..= end).map(Ref::new)
+    fn images(&self) -> impl Iterator<Item = Ref> {
+        (self.images_start .. self.end).map(Ref::new)
+    }
 }
diff --git a/src/layout/mod.rs b/src/layout/mod.rs
index 57add044..28b27899 100644
--- a/src/layout/mod.rs
+++ b/src/layout/mod.rs
@@ -8,7 +8,7 @@ mod spacing;
 mod stack;
 mod text;
 
-use image::RgbaImage;
+use image::RgbImage;
 
 use crate::font::SharedFontLoader;
 use crate::geom::*;
@@ -185,7 +185,7 @@ pub enum LayoutElement {
 #[derive(Debug, Clone, PartialEq)]
 pub struct ImageElement {
     /// The image.
-    pub buf: RgbaImage,
+    pub buf: RgbImage,
     /// The document size of the image.
     pub size: Size,
 }
diff --git a/src/library/insert.rs b/src/library/insert.rs
index 9fe719c7..2904c958 100644
--- a/src/library/insert.rs
+++ b/src/library/insert.rs
@@ -3,7 +3,7 @@ use std::fs::File;
 use std::io::BufReader;
 
 use image::io::Reader;
-use image::RgbaImage;
+use image::RgbImage;
 
 use crate::layout::*;
 use crate::prelude::*;
@@ -25,7 +25,7 @@ pub fn image(mut args: Args, ctx: &mut EvalContext) -> Value {
                 .with_guessed_format()
                 .map_err(|err| err.into())
                 .and_then(|reader| reader.decode())
-                .map(|img| img.into_rgba8())
+                .map(|img| img.into_rgb8())
             {
                 Ok(buf) => {
                     ctx.push(Image {
@@ -49,7 +49,7 @@ pub fn image(mut args: Args, ctx: &mut EvalContext) -> Value {
 #[derive(Clone, PartialEq)]
 struct Image {
     /// The image.
-    buf: RgbaImage,
+    buf: RgbImage,
     /// The fixed width, if any.
     width: Option<Linear>,
     /// The fixed height, if any.
diff --git a/tests/README.md b/tests/README.md
index 3ae908af..6ebba237 100644
--- a/tests/README.md
+++ b/tests/README.md
@@ -5,3 +5,4 @@
 - `png`: PNG files produced by tests
 - `ref`: Reference images which the PNGs are compared to byte-wise to determine
          whether the test passed or failed
+- `res`: Resource files used by tests
diff --git a/tests/typeset.rs b/tests/typeset.rs
index 38651766..d9a1056a 100644
--- a/tests/typeset.rs
+++ b/tests/typeset.rs
@@ -247,8 +247,8 @@ fn draw_text(canvas: &mut Canvas, loader: &FontLoader, shaped: &Shaped, pos: Poi
 fn draw_image(canvas: &mut Canvas, image: &ImageElement, pos: Point) {
     let mut pixmap = Pixmap::new(image.buf.width(), image.buf.height()).unwrap();
     for (src, dest) in image.buf.pixels().zip(pixmap.pixels_mut()) {
-        let [r, g, b, a] = src.0;
-        *dest = ColorU8::from_rgba(r, g, b, a).premultiply();
+        let [r, g, b] = src.0;
+        *dest = ColorU8::from_rgba(r, g, b, 255).premultiply();
     }
 
     let view_width = image.size.width.to_pt() as f32;