fix(html): print a sheet onto the page, without our ruler

CHANGELOG.md

@@ -16,6 +16,10 @@ The release run heads these entries with the version and opens a fresh
 
 ## Unreleased
 
+- A printed sheet drops our row/column ruler and is capped to the page width
+  rather than cut off at the right edge. Print only; the on-screen view is
+  unchanged. Towards #816.
+
 - New `File::name()`: the file name on disk, the entry name inside an archive,
   or the name `File::from_memory(data, name)` was given. A named in-memory file
   gets the same name-derived type candidate a path does, so `notes.md` bytes

src/odr/internal/html/frontend.cpp

@@ -112,6 +112,17 @@ 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. */
+@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 col{min-width:0!important}
+}
 )css";
 
 constexpr std::string_view spreadsheet_dark_css = R"css(

test/src/html_test.cpp

@@ -728,6 +728,24 @@ TEST(html, the_cell_budget_bounds_the_rows_by_the_width) {
   EXPECT_EQ(rendered(30, 3).rows, 5);
 }
 
+// #816
+TEST(html, a_printed_sheet_drops_the_ruler_and_fits_the_page) {
+  const std::string sheet =
+      render("odr-public/ods/file_example_ODS_10.ods", HtmlConfig());
+
+  // on screen the sheet keeps its stated width and its ruler
+  EXPECT_NE(sheet.find("<col style=\"width:"), std::string::npos);
+  EXPECT_NE(sheet.find("table-layout:fixed"), std::string::npos);
+  EXPECT_NE(sheet.find("class=\"odr-sheet-column-header\""), std::string::npos);
+
+  EXPECT_NE(sheet.find(".odr-sheet thead{display:none}"), std::string::npos);
+  EXPECT_NE(sheet.find(".odr-sheet-gutter{visibility:collapse"),
+            std::string::npos);
+  EXPECT_NE(sheet.find(".odr-sheet{max-width:100%}"), std::string::npos);
+  EXPECT_NE(sheet.find(".odr-sheet col{min-width:0!important}"),
+            std::string::npos);
+}
+
 TEST(html, a_view_that_renders_no_sheet_has_no_cut) {
   const DecodedFile file(File::from_memory("<a><b>c</b></a>"), FileType::xml);
   const HtmlService service = html::translate(file, HtmlConfig());