feat(document): fit a printed sheet to the paper the file states

CHANGELOG.md

@@ -16,6 +16,13 @@ The release run heads these entries with the version and opens a fresh
 
 ## Unreleased
 
+- New `Sheet::page_layout()`: the paper an ods states for a sheet, read from
+  the master page its table style names. Mirrored in the Python, JNI and Apple
+  bindings. Empty for xlsx, xls, numbers and csv.
+
+- A printed sheet is fitted to the paper the file states, at the file's own
+  column proportions. Towards #816.
+
 - A right-to-left document renders right-to-left. `style:writing-mode`,
   `w:bidi` and `a:pPr@rtl` are read into a new `TextDirection` on
   `ParagraphStyle` and `PageLayout`, and the view's root carries it as

apple/include/OdrCoreObjC/ODRDocumentElement.h

@@ -117,6 +117,8 @@ NS_SWIFT_NAME(Slide)
 NS_SWIFT_NAME(Sheet)
 @interface ODRSheet : ODRElement
 @property(nonatomic, readonly, copy) NSString *name;
+/// The paper the sheet is printed on, where the file states one.
+@property(nonatomic, readonly) ODRPageLayout *pageLayout;
 @property(nonatomic, readonly) ODRTableDimensions dimensions;
 /// The dimensions actually filled with content, optionally within `range`.
 - (ODRTableDimensions)contentDimensions NS_SWIFT_NAME(contentDimensions());

apple/src/ODRDocumentElement.mm

@@ -308,6 +308,15 @@ - (NSString *)name {
       [&] { return to_nsstring(self.handle.as_sheet().name()); }, @"");
 }
 
+- (ODRPageLayout *)pageLayout {
+  return guarded_value(
+      [&]() -> ODRPageLayout * {
+        return [ODRPageLayout
+            layoutWithHandle:self.handle.as_sheet().page_layout()];
+      },
+      nil);
+}
+
 - (ODRTableDimensions)dimensions {
   return guarded_value(
       [&] { return to_dimensions(self.handle.as_sheet().dimensions()); },

jni/java/app/opendocument/core/Sheet.java

@@ -12,6 +12,11 @@ public String name() {
     return nameNative(handle());
   }
 
+  /** The paper the sheet is printed on, where the file states one. */
+  public PageLayout pageLayout() {
+    return pageLayoutNative(handle());
+  }
+
   public TableDimensions dimensions() {
     return dimensionsNative(handle());
   }
@@ -51,6 +56,8 @@ public TableCellStyle cellStyle(int column, int row) {
 
   private native String nameNative(long handle);
 
+  private native PageLayout pageLayoutNative(long handle);
+
   private native TableDimensions dimensionsNative(long handle);
 
   private native TableDimensions contentNative(long handle, int rows, int columns);

jni/src/jni_document.cpp

@@ -395,6 +395,15 @@ Java_app_opendocument_core_Sheet_nameNative(JNIEnv *env, jobject,
       env, [&] { return to_jstring(env, element(handle).as_sheet().name()); });
 }
 
+extern "C" JNIEXPORT jobject JNICALL
+Java_app_opendocument_core_Sheet_pageLayoutNative(JNIEnv *env, jobject,
+                                                  jlong handle) {
+  return guarded(env, [&] {
+    return odr_jni::make_page_layout(env,
+                                     element(handle).as_sheet().page_layout());
+  });
+}
+
 extern "C" JNIEXPORT jobject JNICALL
 Java_app_opendocument_core_Sheet_dimensionsNative(JNIEnv *env, jobject,
                                                   jlong handle) {

python/src/bind_document.cpp

@@ -191,6 +191,7 @@ void odr_python::bind_document(py::module_ &m) {
 
   bind_element<odr::Sheet>(m, "Sheet")
       .def("name", &odr::Sheet::name)
+      .def("page_layout", &odr::Sheet::page_layout)
       .def("dimensions", &odr::Sheet::dimensions)
       .def("content", &odr::Sheet::content, py::arg("range"))
       .def("cell", &odr::Sheet::cell, py::arg("column"), py::arg("row"),

src/odr/document_element.cpp

@@ -327,6 +327,10 @@ std::string Sheet::name() const {
   return exists_() ? m_adapter2->sheet_name(m_identifier) : "";
 }
 
+PageLayout Sheet::page_layout() const {
+  return exists_() ? m_adapter2->sheet_page_layout(m_identifier) : PageLayout();
+}
+
 TableDimensions Sheet::dimensions() const {
   return exists_() ? m_adapter2->sheet_dimensions(m_identifier)
                    : TableDimensions();

src/odr/document_element.hpp

@@ -312,6 +312,9 @@ class Sheet final : public ElementBase<internal::abstract::SheetAdapter> {
 
   [[nodiscard]] std::string name() const;
 
+  /// The paper the sheet is meant to be printed on, where the file states one.
+  [[nodiscard]] PageLayout page_layout() const;
+
   [[nodiscard]] TableDimensions dimensions() const;
   [[nodiscard]] TableDimensions
   content(std::optional<TableDimensions> range) const;

src/odr/internal/abstract/document.hpp

@@ -258,6 +258,10 @@ class SheetAdapter {
   [[nodiscard]] virtual std::string
   sheet_name(ElementIdentifier element_id) const = 0;
 
+  /// Empty where the file states no paper.
+  [[nodiscard]] virtual PageLayout
+  sheet_page_layout(ElementIdentifier element_id) const = 0;
+
   [[nodiscard]] virtual TableDimensions
   sheet_dimensions(ElementIdentifier element_id) const = 0;
   [[nodiscard]] virtual TableDimensions

src/odr/internal/csv/csv_document.cpp

@@ -160,6 +160,10 @@ class ElementAdapter final : public abstract::ElementAdapter,
       [[maybe_unused]] const ElementIdentifier element_id) const override {
     return "csv";
   }
+  [[nodiscard]] PageLayout sheet_page_layout(
+      [[maybe_unused]] const ElementIdentifier element_id) const override {
+    return {};
+  }
   [[nodiscard]] TableDimensions sheet_dimensions(
       [[maybe_unused]] const ElementIdentifier element_id) const override {
     return m_document->dimensions();

src/odr/internal/html/document_element.cpp

@@ -183,6 +183,40 @@ TableDimensions html::sheet_rendered_extent(const Sheet &sheet,
   return {end_row, end_column};
 }
 
+namespace {
+
+/// How far a sheet has to shrink to fit the paper the file states; nothing
+/// where it fits already, or where no width is stated.
+std::optional<double> sheet_print_fit(const Sheet &sheet,
+                                      const std::uint32_t end_column) {
+  const PageLayout page_layout = sheet.page_layout();
+  const std::optional<double> page = html::css_pixels(page_layout.width);
+  if (!page.has_value()) {
+    return {};
+  }
+  const double printable =
+      *page - html::css_pixels(page_layout.margin.left).value_or(0) -
+      html::css_pixels(page_layout.margin.right).value_or(0);
+
+  // the ruler does not print
+  double content = 0;
+  for (std::uint32_t column = 0; column < end_column; ++column) {
+    const std::optional<double> width =
+        html::css_pixels(sheet.column_style(column).width);
+    if (!width.has_value()) {
+      return {};
+    }
+    content += *width;
+  }
+
+  if (printable <= 0 || content <= printable) {
+    return {};
+  }
+  return printable / content;
+}
+
+} // namespace
+
 std::optional<HtmlSheetCut> html::sheet_cut(const Sheet &sheet,
                                             const HtmlConfig &config) {
   const TableDimensions rendered = sheet_rendered_extent(sheet, config);
@@ -199,13 +233,25 @@ std::optional<HtmlSheetCut> html::sheet_cut(const Sheet &sheet,
 }
 
 void html::translate_sheet(const Sheet &sheet, const WritingState &state) {
-  state.out().write_element_begin("table",
-                                  HtmlElementOptions().set_class("odr-sheet"));
-
   const TableDimensions rendered = sheet_rendered_extent(sheet, state.config());
   const std::uint32_t end_column = rendered.columns;
   const std::uint32_t end_row = rendered.rows;
 
+  const std::optional<double> print_fit = sheet_print_fit(sheet, end_column);
+
+  state.out().write_element_begin(
+      "table", HtmlElementOptions()
+                   .set_class("odr-sheet")
+                   .set_style([&]() -> std::optional<HtmlWritable> {
+                     if (!print_fit.has_value()) {
+                       return std::nullopt;
+                     }
+                     // `Measure` renders no exponent form
+                     return "--odr-print-fit:" +
+                            Measure(*print_fit, DynamicUnit()).to_string() +
+                            ";";
+                   }()));
+
   state.out().write_element_begin("col",
                                   HtmlElementOptions()
                                       .set_close_type(HtmlCloseType::none)

src/odr/internal/html/frontend.cpp

@@ -112,15 +112,15 @@ body{margin:0;background:var(--odr-sheet-canvas)}
 .odr-sheet-sort:hover{background:var(--odr-sheet-wash-ruler)}
 .odr-sheet-sort::after{content:"\25BE";font-size:15px;line-height:1}
 .odr-sheet-sort-asc::after{content:"\25B4"}
-/* Paper cannot scroll, so a sheet wider than the page is cut off; only
-   `!important` beats the inline column width. The ruler collapses rather than
-   `display:none`, which would take the cells out of their rows and shift every
-   column left. */
+/* `--odr-print-fit` is written per sheet by `translate_sheet`; `zoom` keeps
+   the rows breaking across pages. Only `!important` beats the inline column
+   width. The ruler collapses rather than `display:none`, which would take the
+   cells out of their rows and shift every column left. */
 @media print{
 .odr-sheet thead{display:none}
 .odr-sheet-gutter{visibility:collapse;width:0}
 .odr-sheet-row-header{visibility:collapse;padding:0;box-shadow:none}
-.odr-sheet{max-width:100%}
+.odr-sheet{zoom:var(--odr-print-fit,1);max-width:100%}
 .odr-sheet col{min-width:0!important}
 }
 )css";

src/odr/internal/iwork/iwork_document.cpp

@@ -209,6 +209,11 @@ class ElementAdapter final : public abstract::ElementAdapter,
   sheet_name(const ElementIdentifier element_id) const override {
     return m_registry->sheet_element_at(element_id).name;
   }
+  /// TODO the print setup of a `.numbers` sheet is not read.
+  [[nodiscard]] PageLayout sheet_page_layout(
+      [[maybe_unused]] const ElementIdentifier element_id) const override {
+    return {};
+  }
   [[nodiscard]] TableDimensions
   sheet_dimensions(const ElementIdentifier element_id) const override {
     const ElementRegistry::Sheet &sheet =

src/odr/internal/odf/odf_document.cpp

@@ -460,6 +460,21 @@ class ElementAdapter final : public abstract::ElementAdapter,
   sheet_name(const ElementIdentifier element_id) const override {
     return get_node(element_id).attribute("table:name").value();
   }
+  [[nodiscard]] PageLayout
+  sheet_page_layout(const ElementIdentifier element_id) const override {
+    // The table style names the master page (20.383); a sheet that names none
+    // takes the first.
+    ElementIdentifier master_page_id =
+        m_document->style_registry().master_page_of_style(
+            get_node(element_id).attribute("table:style-name").value());
+    if (master_page_id == null_element_id) {
+      master_page_id = m_document->style_registry().first_master_page();
+    }
+    if (master_page_id == null_element_id) {
+      return {};
+    }
+    return master_page_page_layout(master_page_id);
+  }
   [[nodiscard]] TableDimensions
   sheet_dimensions(const ElementIdentifier element_id) const override {
     return m_registry->sheet_element_at(element_id).dimensions;

src/odr/internal/oldms/spreadsheet/xls_document.cpp

@@ -123,6 +123,11 @@ class ElementAdapter final : public abstract::ElementAdapter,
   sheet_name(const ElementIdentifier element_id) const override {
     return m_registry->sheet_element_at(element_id).name;
   }
+  /// TODO `SETUP` ([MS-XLS] 2.4.257) is not read.
+  [[nodiscard]] PageLayout sheet_page_layout(
+      [[maybe_unused]] const ElementIdentifier element_id) const override {
+    return {};
+  }
   [[nodiscard]] TableDimensions
   sheet_dimensions(const ElementIdentifier element_id) const override {
     return m_registry->sheet_element_at(element_id).dimensions;

src/odr/internal/ooxml/spreadsheet/ooxml_spreadsheet_document.cpp

@@ -184,6 +184,11 @@ class ElementAdapter final : public abstract::ElementAdapter,
   sheet_name(const ElementIdentifier element_id) const override {
     return m_registry->sheet_element_at(element_id).name;
   }
+  /// TODO `pageSetup` is not read; a column width here is a `ch` either way.
+  [[nodiscard]] PageLayout sheet_page_layout(
+      [[maybe_unused]] const ElementIdentifier element_id) const override {
+    return {};
+  }
   [[nodiscard]] TableDimensions
   sheet_dimensions(const ElementIdentifier element_id) const override {
     return m_registry->sheet_element_at(element_id).dimensions;

test/src/document_test.cpp

@@ -136,6 +136,43 @@ TEST(Document, docx_page_layout) {
   EXPECT_EQ(Measure("1in"), page_layout.margin.left);
 }
 
+// #816
+TEST(Document, ods_sheet_page_layout) {
+  const Logger logger = Logger::create_stdio("odr-test", LogLevel::verbose);
+
+  const DocumentFile document_file(
+      TestData::test_file_path("odr-public/ods/file_example_ODS_100.ods"),
+      logger);
+
+  const Document document = document_file.document();
+  const PageLayout page_layout =
+      (*document.root_element().children().begin()).as_sheet().page_layout();
+  EXPECT_EQ(Measure("8.2681in"), page_layout.width);
+  EXPECT_EQ(Measure("11.6929in"), page_layout.height);
+  EXPECT_EQ(PrintOrientation::portrait, page_layout.print_orientation);
+  EXPECT_EQ(Measure("0.7874in"), page_layout.margin.top);
+  EXPECT_EQ(Measure("0.7874in"), page_layout.margin.right);
+  EXPECT_EQ(Measure("0.7874in"), page_layout.margin.bottom);
+  EXPECT_EQ(Measure("0.7874in"), page_layout.margin.left);
+}
+
+// Producers commonly state margins only and leave the paper to the printer.
+TEST(Document, ods_sheet_page_layout_without_a_paper_size) {
+  const Logger logger = Logger::create_stdio("odr-test", LogLevel::verbose);
+
+  const DocumentFile document_file(
+      TestData::test_file_path("odr-public/ods/file_example_ODS_10.ods"),
+      logger);
+
+  const Document document = document_file.document();
+  const PageLayout page_layout =
+      (*document.root_element().children().begin()).as_sheet().page_layout();
+
+  EXPECT_FALSE(page_layout.width.has_value());
+  EXPECT_FALSE(page_layout.height.has_value());
+  EXPECT_EQ(Measure("0.7874in"), page_layout.margin.left);
+}
+
 TEST(Document, xlsx_sheet_names) {
   const Logger logger = Logger::create_stdio("odr-test", LogLevel::verbose);