Add parameter to select pages to be exported by CLI (#4039)

crates/typst-cli/src/args.rs

@@ -1,5 +1,8 @@
 use std::fmt::{self, Display, Formatter};
+use std::num::NonZeroUsize;
+use std::ops::RangeInclusive;
 use std::path::PathBuf;
+use std::str::FromStr;
 
 use chrono::{DateTime, Utc};
 use clap::builder::ValueParser;
@@ -76,6 +79,18 @@ pub struct CompileCommand {
     #[clap(required_if_eq("input", "-"), value_parser = ValueParser::new(output_value_parser))]
     pub output: Option<Output>,
 
+    /// Which pages to export. When unspecified, all document pages are exported.
+    ///
+    /// Pages to export are separated by commas, and can be either simple page
+    /// numbers (e.g. '2,5' to export only pages 2 and 5) or page ranges
+    /// (e.g. '2,3-6,8-' to export page 2, pages 3 to 6 (inclusive), page 8 and
+    /// any pages after it).
+    ///
+    /// Page numbers are one-indexed and correspond to real page numbers in the
+    /// document (therefore not being affected by the document's page counter).
+    #[arg(long = "pages", value_delimiter = ',')]
+    pub pages: Option<Vec<PageRangeArgument>>,
+
     /// Output a Makefile rule describing the current compilation
     #[clap(long = "make-deps", value_name = "PATH")]
     pub make_deps: Option<PathBuf>,
@@ -271,6 +286,55 @@ fn parse_input_pair(raw: &str) -> Result<(String, String), String> {
     Ok((key, val))
 }
 
+/// Implements parsing of page ranges (`1-3`, `4`, `5-`, `-2`), used by the
+/// `CompileCommand.pages` argument, through the `FromStr` trait instead of
+/// a value parser, in order to generate better errors.
+///
+/// See also: https://github.com/clap-rs/clap/issues/5065
+#[derive(Debug, Clone)]
+pub struct PageRangeArgument(RangeInclusive<Option<NonZeroUsize>>);
+
+impl PageRangeArgument {
+    pub fn to_range(&self) -> RangeInclusive<Option<NonZeroUsize>> {
+        self.0.clone()
+    }
+}
+
+impl FromStr for PageRangeArgument {
+    type Err = &'static str;
+
+    fn from_str(value: &str) -> Result<Self, Self::Err> {
+        match value.split('-').map(str::trim).collect::<Vec<_>>().as_slice() {
+            [] | [""] => Err("page export range must not be empty"),
+            [single_page] => {
+                let page_number = parse_page_number(single_page)?;
+                Ok(PageRangeArgument(Some(page_number)..=Some(page_number)))
+            }
+            ["", ""] => Err("page export range must have start or end"),
+            [start, ""] => Ok(PageRangeArgument(Some(parse_page_number(start)?)..=None)),
+            ["", end] => Ok(PageRangeArgument(None..=Some(parse_page_number(end)?))),
+            [start, end] => {
+                let start = parse_page_number(start)?;
+                let end = parse_page_number(end)?;
+                if start > end {
+                    Err("page export range must end at a page after the start")
+                } else {
+                    Ok(PageRangeArgument(Some(start)..=Some(end)))
+                }
+            }
+            [_, _, _, ..] => Err("page export range must have a single hyphen"),
+        }
+    }
+}
+
+fn parse_page_number(value: &str) -> Result<NonZeroUsize, &'static str> {
+    if value == "0" {
+        Err("page numbers start at one")
+    } else {
+        NonZeroUsize::from_str(value).map_err(|_| "not a valid page number")
+    }
+}
+
 /// Lists all discovered fonts in system and custom font paths
 #[derive(Debug, Clone, Parser)]
 pub struct FontsCommand {

crates/typst-cli/src/compile.rs

@@ -7,17 +7,19 @@ use codespan_reporting::diagnostic::{Diagnostic, Label};
 use codespan_reporting::term;
 use ecow::{eco_format, EcoString};
 use parking_lot::RwLock;
-use rayon::iter::{IndexedParallelIterator, IntoParallelRefIterator, ParallelIterator};
+use rayon::iter::{IntoParallelRefIterator, ParallelIterator};
 use typst::diag::{bail, At, Severity, SourceDiagnostic, StrResult};
 use typst::eval::Tracer;
 use typst::foundations::{Datetime, Smart};
-use typst::layout::Frame;
+use typst::layout::{Frame, PageRanges};
 use typst::model::Document;
 use typst::syntax::{FileId, Source, Span};
 use typst::visualize::Color;
 use typst::{World, WorldExt};
 
-use crate::args::{CompileCommand, DiagnosticFormat, Input, Output, OutputFormat};
+use crate::args::{
+    CompileCommand, DiagnosticFormat, Input, Output, OutputFormat, PageRangeArgument,
+};
 use crate::timings::Timer;
 use crate::watch::Status;
 use crate::world::SystemWorld;
@@ -60,6 +62,17 @@ impl CompileCommand {
             OutputFormat::Pdf
         })
     }
+
+    /// The ranges of the pages to be exported as specified by the user.
+    ///
+    /// This returns `None` if all pages should be exported.
+    pub fn exported_page_ranges(&self) -> Option<PageRanges> {
+        self.pages.as_ref().map(|export_ranges| {
+            PageRanges::new(
+                export_ranges.iter().map(PageRangeArgument::to_range).collect(),
+            )
+        })
+    }
 }
 
 /// Execute a compilation command.
@@ -171,7 +184,8 @@ fn export_pdf(document: &Document, command: &CompileCommand) -> StrResult<()> {
     let timestamp = convert_datetime(
         command.common.creation_timestamp.unwrap_or_else(chrono::Utc::now),
     );
-    let buffer = typst_pdf::pdf(document, Smart::Auto, timestamp);
+    let exported_page_ranges = command.exported_page_ranges();
+    let buffer = typst_pdf::pdf(document, Smart::Auto, timestamp, exported_page_ranges);
     command
         .output()
         .write(&buffer)
@@ -214,7 +228,21 @@ fn export_image(
             output_template::has_indexable_template(output.to_str().unwrap_or_default())
         }
     };
-    if !can_handle_multiple && document.pages.len() > 1 {
+
+    let exported_page_ranges = command.exported_page_ranges();
+
+    let exported_pages = document
+        .pages
+        .iter()
+        .enumerate()
+        .filter(|(i, _)| {
+            exported_page_ranges.as_ref().map_or(true, |exported_page_ranges| {
+                exported_page_ranges.includes_page_index(*i)
+            })
+        })
+        .collect::<Vec<_>>();
+
+    if !can_handle_multiple && exported_pages.len() > 1 {
         let err = match output {
             Output::Stdout => "to stdout",
             Output::Path(_) => {
@@ -227,10 +255,8 @@ fn export_image(
     let cache = world.export_cache();
 
     // The results are collected in a `Vec<()>` which does not allocate.
-    document
+    exported_pages
-        .pages
         .par_iter()
-        .enumerate()
         .map(|(i, page)| {
             // Use output with converted path.
             let output = match output {
@@ -250,7 +276,7 @@ fn export_image(
                     // If we are not watching, don't use the cache.
                     // If the frame is in the cache, skip it.
                     // If the file does not exist, always create it.
-                    if watching && cache.is_cached(i, &page.frame) && path.exists() {
+                    if watching && cache.is_cached(*i, &page.frame) && path.exists() {
                         return Ok(());
                     }
 

crates/typst-pdf/src/lib.rs

@@ -21,7 +21,7 @@ use pdf_writer::writers::Destination;
 use pdf_writer::{Finish, Name, Pdf, Rect, Ref, Str, TextStr};
 use typst::foundations::{Datetime, Label, NativeElement, Smart};
 use typst::introspection::Location;
-use typst::layout::{Abs, Dir, Em, Frame, Transform};
+use typst::layout::{Abs, Dir, Em, Frame, PageRanges, Transform};
 use typst::model::{Document, HeadingElem};
 use typst::text::color::frame_for_glyph;
 use typst::text::{Font, Lang};
@@ -55,13 +55,17 @@ use crate::pattern::PdfPattern;
 /// The `timestamp`, if given, is expected to be the creation date of the
 /// document as a UTC datetime. It will only be used if `set document(date: ..)`
 /// is `auto`.
+///
+/// The `page_ranges` option specifies which ranges of pages should be exported
+/// in the PDF. When `None`, all pages should be exported.
 #[typst_macros::time(name = "pdf")]
 pub fn pdf(
     document: &Document,
     ident: Smart<&str>,
     timestamp: Option<Datetime>,
+    page_ranges: Option<PageRanges>,
 ) -> Vec<u8> {
-    let mut ctx = PdfContext::new(document);
+    let mut ctx = PdfContext::new(document, page_ranges);
     page::construct_pages(&mut ctx, &document.pages);
     font::write_fonts(&mut ctx);
     image::write_images(&mut ctx);
@@ -82,7 +86,10 @@ struct PdfContext<'a> {
     /// The writer we are writing the PDF into.
     pdf: Pdf,
     /// Content of exported pages.
-    pages: Vec<EncodedPage>,
+    pages: Vec<Option<EncodedPage>>,
+    /// Page ranges to export.
+    /// When `None`, all pages are exported.
+    exported_pages: Option<PageRanges>,
     /// For each font a mapping from used glyphs to their text representation.
     /// May contain multiple chars in case of ligatures or similar things. The
     /// same glyph can have a different text representation within one document,
@@ -108,8 +115,6 @@ struct PdfContext<'a> {
     /// dictionary), which Acrobat doesn't appreciate (it fails to parse the
     /// font) even if the specification seems to allow it.
     type3_font_resources_ref: Ref,
-    /// The IDs of written pages.
-    page_refs: Vec<Ref>,
     /// The IDs of written fonts.
     font_refs: Vec<Ref>,
     /// The IDs of written images.
@@ -145,7 +150,7 @@ struct PdfContext<'a> {
 }
 
 impl<'a> PdfContext<'a> {
-    fn new(document: &'a Document) -> Self {
+    fn new(document: &'a Document, page_ranges: Option<PageRanges>) -> Self {
         let mut alloc = Ref::new(1);
         let page_tree_ref = alloc.bump();
         let global_resources_ref = alloc.bump();
@@ -154,13 +159,13 @@ impl<'a> PdfContext<'a> {
             document,
             pdf: Pdf::new(),
             pages: vec![],
+            exported_pages: page_ranges,
             glyph_sets: HashMap::new(),
             languages: BTreeMap::new(),
             alloc,
             page_tree_ref,
             global_resources_ref,
             type3_font_resources_ref,
-            page_refs: vec![],
             font_refs: vec![],
             image_refs: vec![],
             gradient_refs: vec![],
@@ -251,7 +256,8 @@ fn write_catalog(ctx: &mut PdfContext, ident: Smart<&str>, timestamp: Option<Dat
     }
 
     info.finish();
-    xmp.num_pages(ctx.document.pages.len() as u32);
+    // Only count exported pages.
+    xmp.num_pages(ctx.pages.iter().filter(|page| page.is_some()).count() as u32);
     xmp.format("application/pdf");
     xmp.language(ctx.languages.keys().map(|lang| LangId(lang.as_str())));
 
@@ -350,7 +356,8 @@ fn write_named_destinations(ctx: &mut PdfContext) {
         let index = pos.page.get() - 1;
         let y = (pos.point.y - Abs::pt(10.0)).max(Abs::zero());
 
-        if let Some(page) = ctx.pages.get(index) {
+        // If the heading's page exists and is exported, include it.
+        if let Some(Some(page)) = ctx.pages.get(index) {
             let dest_ref = ctx.alloc.bump();
             let x = pos.point.x.to_f32();
             let y = (page.size.y - y).to_f32();

crates/typst-pdf/src/outline.rs

@@ -18,7 +18,17 @@ pub(crate) fn write_outline(ctx: &mut PdfContext) -> Option<Ref> {
     // enforced in the manner shown below.
     let mut last_skipped_level = None;
     let elements = ctx.document.introspector.query(&HeadingElem::elem().select());
+
     for elem in elements.iter() {
+        if let Some(page_ranges) = &ctx.exported_pages {
+            if !page_ranges
+                .includes_page(ctx.document.introspector.page(elem.location().unwrap()))
+            {
+                // Don't bookmark headings in non-exported pages
+                continue;
+            }
+        }
+
         let heading = elem.to_packed::<HeadingElem>().unwrap();
         let leaf = HeadingNode::leaf(heading);
 
@@ -166,9 +176,11 @@ fn write_outline_item(
     let loc = node.element.location().unwrap();
     let pos = ctx.document.introspector.position(loc);
     let index = pos.page.get() - 1;
-    if let Some(page) = ctx.pages.get(index) {
+
+    // Don't link to non-exported pages.
+    if let Some(Some(page)) = ctx.pages.get(index) {
         let y = (pos.point.y - Abs::pt(10.0)).max(Abs::zero());
-        outline.dest().page(ctx.page_refs[index]).xyz(
+        outline.dest().page(page.id).xyz(
             pos.point.x.to_f32(),
             (page.size.y - y).to_f32(),
             None,

crates/typst-pdf/src/page.rs

@@ -27,20 +27,40 @@ use typst::visualize::{
 /// Construct page objects.
 #[typst_macros::time(name = "construct pages")]
 pub(crate) fn construct_pages(ctx: &mut PdfContext, pages: &[Page]) {
-    for page in pages {
+    let mut skipped_pages = 0;
-        let (page_ref, mut encoded) = construct_page(ctx, &page.frame);
+    for (i, page) in pages.iter().enumerate() {
+        if ctx
+            .exported_pages
+            .as_ref()
+            .is_some_and(|ranges| !ranges.includes_page_index(i))
+        {
+            // Don't export this page.
+            ctx.pages.push(None);
+            skipped_pages += 1;
+        } else {
+            let mut encoded = construct_page(ctx, &page.frame);
             encoded.label = page
                 .numbering
                 .as_ref()
-            .and_then(|num| PdfPageLabel::generate(num, page.number));
+                .and_then(|num| PdfPageLabel::generate(num, page.number))
-        ctx.page_refs.push(page_ref);
+                .or_else(|| {
-        ctx.pages.push(encoded);
+                    // When some pages were ignored from export, we show a page label with
+                    // the correct real (not logical) page number.
+                    // This is for consistency with normal output when pages have no numbering
+                    // and all are exported: the final PDF page numbers always correspond to
+                    // the real (not logical) page numbers. Here, the final PDF page number
+                    // will differ, but we can at least use labels to indicate what was
+                    // the corresponding real page number in the Typst document.
+                    (skipped_pages > 0).then(|| PdfPageLabel::arabic(i + 1))
+                });
+            ctx.pages.push(Some(encoded));
+        }
     }
 }
 
 /// Construct a page object.
 #[typst_macros::time(name = "construct page")]
-pub(crate) fn construct_page(ctx: &mut PdfContext, frame: &Frame) -> (Ref, EncodedPage) {
+pub(crate) fn construct_page(ctx: &mut PdfContext, frame: &Frame) -> EncodedPage {
     let page_ref = ctx.alloc.bump();
 
     let size = frame.size();
@@ -60,7 +80,7 @@ pub(crate) fn construct_page(ctx: &mut PdfContext, frame: &Frame) -> (Ref, Encod
     // Encode the page into the content stream.
     write_frame(&mut ctx, frame);
 
-    let page = EncodedPage {
+    EncodedPage {
         size,
         content: deflate_deferred(ctx.content.finish()),
         id: page_ref,
@@ -68,21 +88,20 @@ pub(crate) fn construct_page(ctx: &mut PdfContext, frame: &Frame) -> (Ref, Encod
         links: ctx.links,
         label: None,
         resources: ctx.resources,
-    };
+    }
-
-    (page_ref, page)
 }
 
 /// Write the page tree.
 pub(crate) fn write_page_tree(ctx: &mut PdfContext) {
+    let mut refs = vec![];
     for i in 0..ctx.pages.len() {
-        write_page(ctx, i);
+        write_page(ctx, i, &mut refs);
     }
 
     ctx.pdf
         .pages(ctx.page_tree_ref)
-        .count(ctx.page_refs.len() as i32)
+        .count(refs.len() as i32)
-        .kids(ctx.page_refs.iter().copied());
+        .kids(refs.iter().copied());
 }
 
 /// Write the global resource dictionary that will be referenced by all pages.
@@ -170,10 +189,15 @@ pub(crate) fn write_global_resources(ctx: &mut PdfContext) {
 }
 
 /// Write a page tree node.
-fn write_page(ctx: &mut PdfContext, i: usize) {
+fn write_page(ctx: &mut PdfContext, i: usize, refs: &mut Vec<Ref>) {
-    let page = &ctx.pages[i];
+    let Some(page) = &ctx.pages[i] else {
+        // Page excluded from export.
+        return;
+    };
     let content_id = ctx.alloc.bump();
 
+    refs.push(page.id);
+
     let mut page_writer = ctx.pdf.page(page.id);
     page_writer.parent(ctx.page_tree_ref);
 
@@ -225,7 +249,8 @@ fn write_page(ctx: &mut PdfContext, i: usize) {
         let index = pos.page.get() - 1;
         let y = (pos.point.y - Abs::pt(10.0)).max(Abs::zero());
 
-        if let Some(page) = ctx.pages.get(index) {
+        // Don't add links to non-exported pages.
+        if let Some(Some(page)) = ctx.pages.get(index) {
             annotation
                 .action()
                 .action_type(ActionType::GoTo)
@@ -244,9 +269,12 @@ fn write_page(ctx: &mut PdfContext, i: usize) {
 }
 
 /// Write the page labels.
+/// They are numbered according to the page's final number, considering pages
+/// which were removed from export, and not according to the page's real or
+/// logical number in the initial Typst document.
 pub(crate) fn write_page_labels(ctx: &mut PdfContext) -> Vec<(NonZeroUsize, Ref)> {
-    // If there is no page labeled, we skip the writing
+    // If there is no exported page labeled, we skip the writing
-    if !ctx.pages.iter().any(|p| {
+    if !ctx.pages.iter().filter_map(Option::as_ref).any(|p| {
         p.label
             .as_ref()
             .is_some_and(|l| l.prefix.is_some() || l.style.is_some())
@@ -258,7 +286,8 @@ pub(crate) fn write_page_labels(ctx: &mut PdfContext) -> Vec<(NonZeroUsize, Ref)
     let empty_label = PdfPageLabel::default();
     let mut prev: Option<&PdfPageLabel> = None;
 
-    for (i, page) in ctx.pages.iter().enumerate() {
+    // Skip non-exported pages for numbering.
+    for (i, page) in ctx.pages.iter().filter_map(Option::as_ref).enumerate() {
         let nr = NonZeroUsize::new(1 + i).unwrap();
         // If there are pages with empty labels between labeled pages, we must
         // write empty PageLabel entries.
@@ -372,6 +401,17 @@ impl PdfPageLabel {
         let offset = style.and(NonZeroUsize::new(number));
         Some(PdfPageLabel { prefix, style, offset })
     }
+
+    /// Creates an arabic page label with the specified page number.
+    /// For example, this will display page label `11` when given the page
+    /// number 11.
+    fn arabic(number: usize) -> PdfPageLabel {
+        PdfPageLabel {
+            prefix: None,
+            style: Some(PdfPageLabelStyle::Arabic),
+            offset: NonZeroUsize::new(number),
+        }
+    }
 }
 
 /// Data for an exported page.

crates/typst-pdf/src/pattern.rs

@@ -116,7 +116,7 @@ fn register_pattern(
     };
 
     // Render the body.
-    let (_, content) = construct_page(ctx.parent, pattern.frame());
+    let content = construct_page(ctx.parent, pattern.frame());
 
     let mut pdf_pattern = PdfPattern {
         transform,

crates/typst/src/layout/page.rs

@@ -1,5 +1,6 @@
 use std::borrow::Cow;
 use std::num::NonZeroUsize;
+use std::ops::RangeInclusive;
 use std::ptr;
 use std::str::FromStr;
 
@@ -726,6 +727,39 @@ cast! {
     v: Func => Self::Func(v),
 }
 
+/// A list of page ranges to be exported. The ranges are one-indexed.
+/// For example, `1..=3` indicates the first, second and third pages should be
+/// exported.
+pub struct PageRanges(Vec<PageRange>);
+
+pub type PageRange = RangeInclusive<Option<NonZeroUsize>>;
+
+impl PageRanges {
+    pub fn new(ranges: Vec<PageRange>) -> Self {
+        Self(ranges)
+    }
+
+    /// Check if a page, given its number, should be included when exporting the
+    /// document while restricting the exported pages to these page ranges.
+    /// This is the one-indexed version of 'includes_page_index'.
+    pub fn includes_page(&self, page: NonZeroUsize) -> bool {
+        self.includes_page_index(page.get() - 1)
+    }
+
+    /// Check if a page, given its index, should be included when exporting the
+    /// document while restricting the exported pages to these page ranges.
+    /// This is the zero-indexed version of 'includes_page'.
+    pub fn includes_page_index(&self, page: usize) -> bool {
+        let page = NonZeroUsize::try_from(page + 1).unwrap();
+        self.0.iter().any(|range| match (range.start(), range.end()) {
+            (Some(start), Some(end)) => (start..=end).contains(&&page),
+            (Some(start), None) => (start..).contains(&&page),
+            (None, Some(end)) => (..=end).contains(&&page),
+            (None, None) => true,
+        })
+    }
+}
+
 /// A manual page break.
 ///
 /// Must not be used inside any containers.

tests/src/run.rs

@@ -176,7 +176,7 @@ impl<'a> Runner<'a> {
         // Write PDF if requested.
         if crate::ARGS.pdf() {
             let pdf_path = format!("{}/pdf/{}.pdf", crate::STORE_PATH, self.test.name);
-            let pdf = typst_pdf::pdf(document, Smart::Auto, None);
+            let pdf = typst_pdf::pdf(document, Smart::Auto, None, None);
             std::fs::write(pdf_path, pdf).unwrap();
         }