fix(pdf): apply the /ExtGState stroke parameters, not just the alphas

CHANGELOG.md

@@ -16,6 +16,10 @@ The release run heads these entries with the version and opens a fresh
 
 ## Unreleased
 
+- A PDF `gs` applies the `/ExtGState` stroke parameters `/LW`, `/LC`, `/LJ`,
+  `/ML` and `/D`. A producer that sets the line width only there — Canva does —
+  used to have every stroke drawn at the initial width of 1.
+
 - A manual page break starts a new page box, and prints as `break-before:page`.
   New `BreakType` and `ParagraphStyle::break_before`/`break_after`, mirrored in
   the JNI, Apple and Python bindings. Towards #174.

src/odr/internal/pdf/pdf_page_extractor.cpp

@@ -14,6 +14,7 @@
 
 #include <array>
 #include <cmath>
+#include <cstdint>
 #include <memory>
 #include <optional>
 #include <ranges>
@@ -335,8 +336,9 @@ build_soft_mask(const SoftMaskDef &def, const Resources &resources,
                 GraphicsState &state, const Logger &logger,
                 std::set<std::string> &warned, ActiveForms &active);
 
-/// Apply `gs` (ISO 32000-1 8.4.5): fold the named `/ExtGState`'s `ca`/`CA`,
-/// `/BM` and `/SMask` into the general state. Other entries are out of scope.
+/// Apply `gs` (ISO 32000-1 8.4.5): fold the named `/ExtGState`'s stroke
+/// parameters (`/LW`, `/LC`, `/LJ`, `/ML`, `/D`), `ca`/`CA`, `/BM` and
+/// `/SMask` into the general state. Other entries are out of scope.
 /// `/BM` may be an array — an ordered fallback list, so pick the first
 /// supported name. An absent `/SMask` leaves the mask unchanged; `/None`
 /// clears it.
@@ -349,6 +351,30 @@ void apply_ext_g_state(const std::string &name, const Resources &resources,
   }
   const Dictionary &dictionary = it->second.as_dictionary();
   GraphicsState::General &general = state.current().general;
+  // Table 58's aliases for `w`/`J`/`j`/`M`/`d`. A producer that sets the line
+  // width only here (Canva does) strokes at the initial width of 1 without
+  // them.
+  if (dictionary.has_value("LW") && dictionary.at("LW").is_real()) {
+    general.line_width = dictionary.at("LW").as_real();
+  }
+  if (dictionary.has_value("LC") && dictionary.at("LC").is_integer()) {
+    general.cap_style =
+        static_cast<std::int32_t>(dictionary.at("LC").as_integer());
+  }
+  if (dictionary.has_value("LJ") && dictionary.at("LJ").is_integer()) {
+    general.join_style =
+        static_cast<std::int32_t>(dictionary.at("LJ").as_integer());
+  }
+  if (dictionary.has_value("ML") && dictionary.at("ML").is_real()) {
+    general.miter_limit = dictionary.at("ML").as_real();
+  }
+  // `/D` is `[[array] phase]`, the two `d` operands in one array.
+  if (dictionary.has_value("D") && dictionary.at("D").is_array()) {
+    const Array &dash = dictionary.at("D").as_array();
+    if (dash.size() == 2 && dash[0].is_array() && dash[1].is_real()) {
+      general.dash = {dash[0].as_reals(), dash[1].as_real()};
+    }
+  }
   if (dictionary.has_value("ca") && dictionary.at("ca").is_real()) {
     general.fill_alpha = dictionary.at("ca").as_real();
   }

test/data.cmake

@@ -12,7 +12,7 @@ odr_test_data(
 odr_test_data(
         PATH "input/odr-private"
         URL "https://github.com/opendocument-app/OpenDocument.test-private.git"
-        REVISION "b71cec155018311c130b98c07ddee5e853db9e26")
+        REVISION "d0bedc89b67e73a2e4113f96f27d1d1cdf30c69f")
 
 odr_test_data(
         PATH "reference-output/odr-public"
@@ -22,4 +22,4 @@ odr_test_data(
 odr_test_data(
         PATH "reference-output/odr-private"
         URL "https://github.com/opendocument-app/OpenDocument.test-private.output.git"
-        REVISION "9e9cc5859cc2c2c36d973f6a568133e2ecc4ec35")
+        REVISION "2f5964b9b8a5172aac2e4f0d893c6ccf625f8857")

test/src/internal/pdf/pdf_page_extractor.cpp

@@ -843,6 +843,50 @@ TEST(PdfPageExtractor, gs_blend_mode_array_picks_first_supported) {
   EXPECT_EQ(path_at(page, 0).blend_mode, "Multiply");
 }
 
+// `/LW` is the `w` operator as an `/ExtGState` entry (ISO 32000-1 Table 58);
+// a producer that sets the width only there used to stroke at the initial 1.
+TEST(PdfPageExtractor, gs_line_width) {
+  Resources res;
+  Dictionary gs;
+  gs["LW"] = Object(Real{3.5});
+  res.ext_g_state["GS1"] = Object(std::move(gs));
+  const auto page =
+      extract_page("/GS1 gs 0 0 m 10 10 l S", res, Logger::null());
+  ASSERT_EQ(page.size(), 1);
+  EXPECT_DOUBLE_EQ(path_at(page, 0).line_width, 3.5);
+}
+
+// `/LC`, `/LJ` and `/ML` alias `J`, `j` and `M`.
+TEST(PdfPageExtractor, gs_line_cap_join_and_miter_limit) {
+  Resources res;
+  Dictionary gs;
+  gs["LC"] = Object(Integer{1});
+  gs["LJ"] = Object(Integer{2});
+  gs["ML"] = Object(Real{4});
+  res.ext_g_state["GS1"] = Object(std::move(gs));
+  const auto page =
+      extract_page("/GS1 gs 0 0 m 10 10 l S", res, Logger::null());
+  ASSERT_EQ(page.size(), 1);
+  EXPECT_EQ(path_at(page, 0).line_cap, 1);
+  EXPECT_EQ(path_at(page, 0).line_join, 2);
+  EXPECT_DOUBLE_EQ(path_at(page, 0).miter_limit, 4);
+}
+
+// `/D` packs both `d` operands into one array: `[[array] phase]`.
+TEST(PdfPageExtractor, gs_dash_pattern) {
+  Resources res;
+  Dictionary gs;
+  gs["D"] = Object(Array(std::vector<Object>{
+      Object(Array(std::vector<Object>{Object(Real{3}), Object(Real{2})})),
+      Object(Real{1})}));
+  res.ext_g_state["GS1"] = Object(std::move(gs));
+  const auto page =
+      extract_page("/GS1 gs 0 0 m 10 10 l S", res, Logger::null());
+  ASSERT_EQ(page.size(), 1);
+  EXPECT_EQ(path_at(page, 0).dash_array, (std::vector<double>{3, 2}));
+  EXPECT_DOUBLE_EQ(path_at(page, 0).dash_phase, 1);
+}
+
 // The constant alpha is part of the saved graphics state, so `q`/`Q` scope it.
 TEST(PdfPageExtractor, gs_alpha_scoped_by_q_Q) {
   Resources res;