LibPDF: Propagate errors in Renderer/PDFViewer

Userland/Applications/PDFViewer/PDFViewer.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Matthew Olsson <mattco@serenityos.org>
+ * Copyright (c) 2021-2022, Matthew Olsson <mattco@serenityos.org>
  * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -8,6 +8,7 @@
 #include "PDFViewer.h"
 #include <AK/Array.h>
 #include <LibGUI/Action.h>
+#include <LibGUI/MessageBox.h>
 #include <LibGUI/Painter.h>
 #include <LibPDF/Renderer.h>
 
@@ -56,15 +57,15 @@ void PDFViewer::set_document(RefPtr<PDF::Document> document)
     update();
 }
 
-RefPtr<Gfx::Bitmap> PDFViewer::get_rendered_page(u32 index)
+PDF::PDFErrorOr<NonnullRefPtr<Gfx::Bitmap>> PDFViewer::get_rendered_page(u32 index)
 {
     auto& rendered_page_map = m_rendered_page_list[index];
     auto existing_rendered_page = rendered_page_map.get(m_zoom_level);
     if (existing_rendered_page.has_value() && existing_rendered_page.value().rotation == m_rotations)
         return existing_rendered_page.value().bitmap;
 
-    // FIXME: Propogate errors in the Renderer
+    auto page = TRY(m_document->get_page(index));
-    auto rendered_page = render_page(MUST(m_document->get_page(index)));
+    auto rendered_page = TRY(render_page(page));
     rendered_page_map.set(m_zoom_level, { rendered_page, m_rotations });
     return rendered_page;
 }
@@ -81,7 +82,14 @@ void PDFViewer::paint_event(GUI::PaintEvent& event)
     if (!m_document)
         return;
 
-    auto page = get_rendered_page(m_current_page_index);
+    auto maybe_page = get_rendered_page(m_current_page_index);
+    if (maybe_page.is_error()) {
+        auto error = maybe_page.release_error();
+        GUI::MessageBox::show_error(nullptr, String::formatted("Error rendering page:\n{}", error.message()));
+        return;
+    }
+
+    auto page = maybe_page.release_value();
     set_content_size(page->size());
 
     painter.translate(frame_thickness(), frame_thickness());
@@ -196,7 +204,7 @@ void PDFViewer::rotate(int degrees)
     update();
 }
 
-RefPtr<Gfx::Bitmap> PDFViewer::render_page(const PDF::Page& page)
+PDF::PDFErrorOr<NonnullRefPtr<Gfx::Bitmap>> PDFViewer::render_page(const PDF::Page& page)
 {
     auto zoom_scale_factor = static_cast<float>(zoom_levels[m_zoom_level]) / 100.0f;
 
@@ -208,7 +216,7 @@ RefPtr<Gfx::Bitmap> PDFViewer::render_page(const PDF::Page& page)
     auto width = height / page_scale_factor;
     auto bitmap = Gfx::Bitmap::try_create(Gfx::BitmapFormat::BGRA8888, { width, height }).release_value_but_fixme_should_propagate_errors();
 
-    PDF::Renderer::render(*m_document, page, bitmap);
+    TRY(PDF::Renderer::render(*m_document, page, bitmap));
 
     if (page.rotate + m_rotations != 0) {
         int rotation_count = ((page.rotate + m_rotations) / 90) % 4;

Userland/Applications/PDFViewer/PDFViewer.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Matthew Olsson <mattco@serenityos.org>
+ * Copyright (c) 2021-2022, Matthew Olsson <mattco@serenityos.org>
  * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -45,12 +45,12 @@ protected:
 
 private:
     struct RenderedPage {
-        RefPtr<Gfx::Bitmap> bitmap;
+        NonnullRefPtr<Gfx::Bitmap> bitmap;
         int rotation;
     };
 
-    RefPtr<Gfx::Bitmap> get_rendered_page(u32 index);
+    PDF::PDFErrorOr<NonnullRefPtr<Gfx::Bitmap>> get_rendered_page(u32 index);
-    RefPtr<Gfx::Bitmap> render_page(const PDF::Page&);
+    PDF::PDFErrorOr<NonnullRefPtr<Gfx::Bitmap>> render_page(const PDF::Page&);
 
     RefPtr<PDF::Document> m_document;
     u32 m_current_page_index { 0 };

Userland/Libraries/LibPDF/Renderer.cpp

@@ -9,7 +9,7 @@
 #include <LibPDF/Renderer.h>
 
 #define RENDERER_HANDLER(name) \
-    void Renderer::handle_##name([[maybe_unused]] Vector<Value> const& args)
+    PDFErrorOr<void> Renderer::handle_##name([[maybe_unused]] Vector<Value> const& args)
 
 #define RENDERER_TODO(name)                                         \
     RENDERER_HANDLER(name)                                          \
@@ -20,9 +20,9 @@
 
 namespace PDF {
 
-void Renderer::render(Document& document, Page const& page, RefPtr<Gfx::Bitmap> bitmap)
+PDFErrorOr<void> Renderer::render(Document& document, Page const& page, RefPtr<Gfx::Bitmap> bitmap)
 {
-    Renderer(document, page, bitmap).render();
+    return Renderer(document, page, bitmap).render();
 }
 
 Renderer::Renderer(RefPtr<Document> document, Page const& page, RefPtr<Gfx::Bitmap> bitmap)
@@ -56,7 +56,7 @@ Renderer::Renderer(RefPtr<Document> document, Page const& page, RefPtr<Gfx::Bitm
     m_bitmap->fill(Gfx::Color::NamedColor::White);
 }
 
-void Renderer::render()
+PDFErrorOr<void> Renderer::render()
 {
     // Use our own vector, as the /Content can be an array with multiple
     // streams which gets concatenated
@@ -68,7 +68,7 @@ void Renderer::render()
     if (m_page.contents->is<ArrayObject>()) {
         auto contents = m_page.contents->cast<ArrayObject>();
         for (auto& ref : *contents) {
-            auto bytes = MUST(m_document->resolve_to<StreamObject>(ref))->bytes();
+            auto bytes = TRY(m_document->resolve_to<StreamObject>(ref))->bytes();
             byte_buffer.append(bytes.data(), bytes.size());
         }
     } else {
@@ -76,38 +76,44 @@ void Renderer::render()
         byte_buffer.append(bytes.data(), bytes.size());
     }
 
-    auto commands = MUST(Parser::parse_graphics_commands(byte_buffer));
+    auto commands = TRY(Parser::parse_graphics_commands(byte_buffer));
 
     for (auto& command : commands)
-        handle_command(command);
+        TRY(handle_command(command));
+
+    return {};
 }
 
-void Renderer::handle_command(Command const& command)
+PDFErrorOr<void> Renderer::handle_command(Command const& command)
 {
     switch (command.command_type()) {
-#define V(name, snake_name, symbol)               \
+#define V(name, snake_name, symbol)                    \
-    case CommandType::name:                       \
+    case CommandType::name:                            \
-        handle_##snake_name(command.arguments()); \
+        TRY(handle_##snake_name(command.arguments())); \
         break;
         ENUMERATE_COMMANDS(V)
 #undef V
     case CommandType::TextNextLineShowString:
-        handle_text_next_line_show_string(command.arguments());
+        TRY(handle_text_next_line_show_string(command.arguments()));
         break;
     case CommandType::TextNextLineShowStringSetSpacing:
-        handle_text_next_line_show_string_set_spacing(command.arguments());
+        TRY(handle_text_next_line_show_string_set_spacing(command.arguments()));
         break;
     }
+
+    return {};
 }
 
 RENDERER_HANDLER(save_state)
 {
     m_graphics_state_stack.append(state());
+    return {};
 }
 
 RENDERER_HANDLER(restore_state)
 {
     m_graphics_state_stack.take_last();
+    return {};
 }
 
 RENDERER_HANDLER(concatenate_matrix)
@@ -122,26 +128,31 @@ RENDERER_HANDLER(concatenate_matrix)
 
     state().ctm.multiply(new_transform);
     m_text_rendering_matrix_is_dirty = true;
+    return {};
 }
 
 RENDERER_HANDLER(set_line_width)
 {
     state().line_width = args[0].to_float();
+    return {};
 }
 
 RENDERER_HANDLER(set_line_cap)
 {
     state().line_cap_style = static_cast<LineCapStyle>(args[0].get<int>());
+    return {};
 }
 
 RENDERER_HANDLER(set_line_join)
 {
     state().line_join_style = static_cast<LineJoinStyle>(args[0].get<int>());
+    return {};
 }
 
 RENDERER_HANDLER(set_miter_limit)
 {
     state().miter_limit = args[0].to_float();
+    return {};
 }
 
 RENDERER_HANDLER(set_dash_pattern)
@@ -151,10 +162,11 @@ RENDERER_HANDLER(set_dash_pattern)
     for (auto& element : *dash_array)
         pattern.append(element.get<int>());
     state().line_dash_pattern = LineDashPattern { pattern, args[1].get<int>() };
+    return {};
 }
 
-RENDERER_TODO(set_color_rendering_intent);
+RENDERER_TODO(set_color_rendering_intent)
-RENDERER_TODO(set_flatness_tolerance);
+RENDERER_TODO(set_flatness_tolerance)
 
 RENDERER_HANDLER(set_graphics_state_from_dict)
 {
@@ -162,27 +174,31 @@ RENDERER_HANDLER(set_graphics_state_from_dict)
     auto dict_name = MUST(m_document->resolve_to<NameObject>(args[0]))->name();
     auto ext_gstate_dict = MUST(m_page.resources->get_dict(m_document, CommonNames::ExtGState));
     auto target_dict = MUST(ext_gstate_dict->get_dict(m_document, dict_name));
-    set_graphics_state_from_dict(target_dict);
+    TRY(set_graphics_state_from_dict(target_dict));
+    return {};
 }
 
 RENDERER_HANDLER(path_move)
 {
     m_current_path.move_to(map(args[0].to_float(), args[1].to_float()));
+    return {};
 }
 
 RENDERER_HANDLER(path_line)
 {
     VERIFY(!m_current_path.segments().is_empty());
     m_current_path.line_to(map(args[0].to_float(), args[1].to_float()));
+    return {};
 }
 
-RENDERER_TODO(path_cubic_bezier_curve);
+RENDERER_TODO(path_cubic_bezier_curve)
-RENDERER_TODO(path_cubic_bezier_curve_no_first_control);
+RENDERER_TODO(path_cubic_bezier_curve_no_first_control)
-RENDERER_TODO(path_cubic_bezier_curve_no_second_control);
+RENDERER_TODO(path_cubic_bezier_curve_no_second_control)
 
 RENDERER_HANDLER(path_close)
 {
     m_current_path.close();
+    return {};
 }
 
 RENDERER_HANDLER(path_append_rect)
@@ -195,63 +211,74 @@ RENDERER_HANDLER(path_append_rect)
     m_current_path.line_to({ pos.x() + size.width(), pos.y() + size.height() });
     m_current_path.line_to({ pos.x(), pos.y() + size.height() });
     m_current_path.close();
+    return {};
 }
 
 RENDERER_HANDLER(path_stroke)
 {
     m_painter.stroke_path(m_current_path, state().stroke_color, state().line_width);
     m_current_path.clear();
+    return {};
 }
 
 RENDERER_HANDLER(path_close_and_stroke)
 {
     m_current_path.close();
-    handle_path_stroke(args);
+    TRY(handle_path_stroke(args));
+    return {};
 }
 
 RENDERER_HANDLER(path_fill_nonzero)
 {
     m_painter.fill_path(m_current_path, state().paint_color, Gfx::Painter::WindingRule::Nonzero);
     m_current_path.clear();
+    return {};
 }
 
 RENDERER_HANDLER(path_fill_nonzero_deprecated)
 {
-    handle_path_fill_nonzero(args);
+    TRY(handle_path_fill_nonzero(args));
+    return {};
 }
 
 RENDERER_HANDLER(path_fill_evenodd)
 {
     m_painter.fill_path(m_current_path, state().paint_color, Gfx::Painter::WindingRule::EvenOdd);
     m_current_path.clear();
+    return {};
 }
 
 RENDERER_HANDLER(path_fill_stroke_nonzero)
 {
     m_painter.stroke_path(m_current_path, state().stroke_color, state().line_width);
-    handle_path_fill_nonzero(args);
+    TRY(handle_path_fill_nonzero(args));
+    return {};
 }
 
 RENDERER_HANDLER(path_fill_stroke_evenodd)
 {
     m_painter.stroke_path(m_current_path, state().stroke_color, state().line_width);
-    handle_path_fill_evenodd(args);
+    TRY(handle_path_fill_evenodd(args));
+    return {};
 }
 
 RENDERER_HANDLER(path_close_fill_stroke_nonzero)
 {
     m_current_path.close();
-    handle_path_fill_stroke_nonzero(args);
+    TRY(handle_path_fill_stroke_nonzero(args));
+    return {};
 }
 
 RENDERER_HANDLER(path_close_fill_stroke_evenodd)
 {
     m_current_path.close();
-    handle_path_fill_stroke_evenodd(args);
+    TRY(handle_path_fill_stroke_evenodd(args));
+    return {};
 }
 
 RENDERER_HANDLER(path_end)
 {
+    return {};
 }
 
 RENDERER_HANDLER(path_intersect_clip_nonzero)
@@ -259,6 +286,7 @@ RENDERER_HANDLER(path_intersect_clip_nonzero)
     // FIXME: Support arbitrary path clipping in the painter and utilize that here
     auto bounding_box = map(m_current_path.bounding_box());
     m_painter.add_clip_rect(bounding_box.to_type<int>());
+    return {};
 }
 
 RENDERER_HANDLER(path_intersect_clip_evenodd)
@@ -266,38 +294,45 @@ RENDERER_HANDLER(path_intersect_clip_evenodd)
     // FIXME: Support arbitrary path clipping in the painter and utilize that here
     auto bounding_box = map(m_current_path.bounding_box());
     m_painter.add_clip_rect(bounding_box.to_type<int>());
+    return {};
 }
 
 RENDERER_HANDLER(text_begin)
 {
     m_text_matrix = Gfx::AffineTransform();
     m_text_line_matrix = Gfx::AffineTransform();
+    return {};
 }
 
 RENDERER_HANDLER(text_end)
 {
     // FIXME: Do we need to do anything here?
+    return {};
 }
 
 RENDERER_HANDLER(text_set_char_space)
 {
     text_state().character_spacing = args[0].to_float();
+    return {};
 }
 
 RENDERER_HANDLER(text_set_word_space)
 {
     text_state().word_spacing = args[0].to_float();
+    return {};
 }
 
 RENDERER_HANDLER(text_set_horizontal_scale)
 {
     m_text_rendering_matrix_is_dirty = true;
     text_state().horizontal_scaling = args[0].to_float() / 100.0f;
+    return {};
 }
 
 RENDERER_HANDLER(text_set_leading)
 {
     text_state().leading = args[0].to_float();
+    return {};
 }
 
 RENDERER_HANDLER(text_set_font)
@@ -330,17 +365,20 @@ RENDERER_HANDLER(text_set_font)
     text_state().font_variant = font_variant;
 
     m_text_rendering_matrix_is_dirty = true;
+    return {};
 }
 
 RENDERER_HANDLER(text_set_rendering_mode)
 {
     text_state().rendering_mode = static_cast<TextRenderingMode>(args[0].get<int>());
+    return {};
 }
 
 RENDERER_HANDLER(text_set_rise)
 {
     m_text_rendering_matrix_is_dirty = true;
     text_state().rise = args[0].to_float();
+    return {};
 }
 
 RENDERER_HANDLER(text_next_line_offset)
@@ -350,12 +388,14 @@ RENDERER_HANDLER(text_next_line_offset)
     m_text_matrix = transform;
     m_text_line_matrix = transform;
     m_text_rendering_matrix_is_dirty = true;
+    return {};
 }
 
 RENDERER_HANDLER(text_next_line_and_set_leading)
 {
     text_state().leading = -args[1].to_float();
-    handle_text_next_line_offset(args);
+    TRY(handle_text_next_line_offset(args));
+    return {};
 }
 
 RENDERER_HANDLER(text_set_matrix_and_line_matrix)
@@ -370,26 +410,30 @@ RENDERER_HANDLER(text_set_matrix_and_line_matrix)
     m_text_line_matrix = new_transform;
     m_text_matrix = new_transform;
     m_text_rendering_matrix_is_dirty = true;
+    return {};
 }
 
 RENDERER_HANDLER(text_next_line)
 {
-    handle_text_next_line_offset({ 0.0f, -text_state().leading });
+    TRY(handle_text_next_line_offset({ 0.0f, -text_state().leading }));
+    return {};
 }
 
 RENDERER_HANDLER(text_show_string)
 {
     auto text = MUST(m_document->resolve_to<StringObject>(args[0]))->string();
     show_text(text);
+    return {};
 }
 
 RENDERER_HANDLER(text_next_line_show_string)
 {
-    handle_text_next_line(args);
+    TRY(handle_text_next_line(args));
-    handle_text_show_string(args);
+    TRY(handle_text_show_string(args));
+    return {};
 }
 
-RENDERER_TODO(text_next_line_show_string_set_spacing);
+RENDERER_TODO(text_next_line_show_string_set_spacing)
 
 RENDERER_HANDLER(text_show_string_array)
 {
@@ -406,85 +450,97 @@ RENDERER_HANDLER(text_show_string_array)
             show_text(str, next_shift);
         }
     }
+
+    return {};
 }
 
-RENDERER_TODO(type3_font_set_glyph_width);
+RENDERER_TODO(type3_font_set_glyph_width)
-RENDERER_TODO(type3_font_set_glyph_width_and_bbox);
+RENDERER_TODO(type3_font_set_glyph_width_and_bbox)
 
 RENDERER_HANDLER(set_stroking_space)
 {
     state().stroke_color_space = MUST(get_color_space(args[0]));
     VERIFY(state().stroke_color_space);
+    return {};
 }
 
 RENDERER_HANDLER(set_painting_space)
 {
     state().paint_color_space = MUST(get_color_space(args[0]));
     VERIFY(state().paint_color_space);
+    return {};
 }
 
 RENDERER_HANDLER(set_stroking_color)
 {
     state().stroke_color = state().stroke_color_space->color(args);
+    return {};
 }
 
-RENDERER_TODO(set_stroking_color_extended);
+RENDERER_TODO(set_stroking_color_extended)
 
 RENDERER_HANDLER(set_painting_color)
 {
     state().paint_color = state().paint_color_space->color(args);
+    return {};
 }
 
-RENDERER_TODO(set_painting_color_extended);
+RENDERER_TODO(set_painting_color_extended)
 
 RENDERER_HANDLER(set_stroking_color_and_space_to_gray)
 {
     state().stroke_color_space = DeviceGrayColorSpace::the();
     state().stroke_color = state().stroke_color_space->color(args);
+    return {};
 }
 
 RENDERER_HANDLER(set_painting_color_and_space_to_gray)
 {
     state().paint_color_space = DeviceGrayColorSpace::the();
     state().paint_color = state().paint_color_space->color(args);
+    return {};
 }
 
 RENDERER_HANDLER(set_stroking_color_and_space_to_rgb)
 {
     state().stroke_color_space = DeviceRGBColorSpace::the();
     state().stroke_color = state().stroke_color_space->color(args);
+    return {};
 }
 
 RENDERER_HANDLER(set_painting_color_and_space_to_rgb)
 {
     state().paint_color_space = DeviceRGBColorSpace::the();
     state().paint_color = state().paint_color_space->color(args);
+    return {};
 }
 
 RENDERER_HANDLER(set_stroking_color_and_space_to_cmyk)
 {
     state().stroke_color_space = DeviceCMYKColorSpace::the();
     state().stroke_color = state().stroke_color_space->color(args);
+    return {};
 }
 
 RENDERER_HANDLER(set_painting_color_and_space_to_cmyk)
 {
     state().paint_color_space = DeviceCMYKColorSpace::the();
     state().paint_color = state().paint_color_space->color(args);
+    return {};
 }
 
-RENDERER_TODO(shade);
+RENDERER_TODO(shade)
-RENDERER_TODO(inline_image_begin);
+RENDERER_TODO(inline_image_begin)
-RENDERER_TODO(inline_image_begin_data);
+RENDERER_TODO(inline_image_begin_data)
-RENDERER_TODO(inline_image_end);
+RENDERER_TODO(inline_image_end)
-RENDERER_TODO(paint_xobject);
+RENDERER_TODO(paint_xobject)
-RENDERER_TODO(marked_content_point);
+RENDERER_TODO(marked_content_point)
-RENDERER_TODO(marked_content_designate);
+RENDERER_TODO(marked_content_designate)
-RENDERER_TODO(marked_content_begin);
+RENDERER_TODO(marked_content_begin)
-RENDERER_TODO(marked_content_begin_with_property_list);
+RENDERER_TODO(marked_content_begin_with_property_list)
-RENDERER_TODO(marked_content_end);
+RENDERER_TODO(marked_content_end)
-RENDERER_TODO(compatibility_begin);
+RENDERER_TODO(compatibility_begin)
-RENDERER_TODO(compatibility_end);
+RENDERER_TODO(compatibility_end)
 
 template<typename T>
 Gfx::Point<T> Renderer::map(T x, T y) const
@@ -505,25 +561,29 @@ Gfx::Rect<T> Renderer::map(Gfx::Rect<T> rect) const
     return state().ctm.map(rect);
 }
 
-void Renderer::set_graphics_state_from_dict(NonnullRefPtr<DictObject> dict)
+PDFErrorOr<void> Renderer::set_graphics_state_from_dict(NonnullRefPtr<DictObject> dict)
 {
     if (dict->contains(CommonNames::LW))
-        handle_set_line_width({ dict->get_value(CommonNames::LW) });
+        TRY(handle_set_line_width({ dict->get_value(CommonNames::LW) }));
 
     if (dict->contains(CommonNames::LC))
-        handle_set_line_cap({ dict->get_value(CommonNames::LC) });
+        TRY(handle_set_line_cap({ dict->get_value(CommonNames::LC) }));
 
     if (dict->contains(CommonNames::LJ))
-        handle_set_line_join({ dict->get_value(CommonNames::LJ) });
+        TRY(handle_set_line_join({ dict->get_value(CommonNames::LJ) }));
 
     if (dict->contains(CommonNames::ML))
-        handle_set_miter_limit({ dict->get_value(CommonNames::ML) });
+        TRY(handle_set_miter_limit({ dict->get_value(CommonNames::ML) }));
 
-    if (dict->contains(CommonNames::D))
+    if (dict->contains(CommonNames::D)) {
-        handle_set_dash_pattern(MUST(dict->get_array(m_document, CommonNames::D))->elements());
+        auto array = MUST(dict->get_array(m_document, CommonNames::D));
+        TRY(handle_set_dash_pattern(array->elements()));
+    }
 
     if (dict->contains(CommonNames::FL))
-        handle_set_flatness_tolerance({ dict->get_value(CommonNames::FL) });
+        TRY(handle_set_flatness_tolerance({ dict->get_value(CommonNames::FL) }));
+
+    return {};
 }
 
 void Renderer::show_text(String const& string, float shift)

Userland/Libraries/LibPDF/Renderer.h

@@ -79,22 +79,22 @@ struct GraphicsState {
 
 class Renderer {
 public:
-    static void render(Document&, Page const&, RefPtr<Gfx::Bitmap>);
+    static PDFErrorOr<void> render(Document&, Page const&, RefPtr<Gfx::Bitmap>);
 
 private:
     Renderer(RefPtr<Document>, Page const&, RefPtr<Gfx::Bitmap>);
 
-    void render();
+    PDFErrorOr<void> render();
 
-    void handle_command(Command const&);
+    PDFErrorOr<void> handle_command(Command const&);
 #define V(name, snake_name, symbol) \
-    void handle_##snake_name(Vector<Value> const& args);
+    PDFErrorOr<void> handle_##snake_name(Vector<Value> const& args);
     ENUMERATE_COMMANDS(V)
 #undef V
-    void handle_text_next_line_show_string(Vector<Value> const& args);
+    PDFErrorOr<void> handle_text_next_line_show_string(Vector<Value> const& args);
-    void handle_text_next_line_show_string_set_spacing(Vector<Value> const& args);
+    PDFErrorOr<void> handle_text_next_line_show_string_set_spacing(Vector<Value> const& args);
 
-    void set_graphics_state_from_dict(NonnullRefPtr<DictObject>);
+    PDFErrorOr<void> set_graphics_state_from_dict(NonnullRefPtr<DictObject>);
     // shift is the manual advance given in the TJ command array
     void show_text(String const&, float shift = 0.0f);
     PDFErrorOr<NonnullRefPtr<ColorSpace>> get_color_space(Value const&);