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LibPDF: Fix text positioning with operator TJ

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As per spec, the positioning (or kerning) parameter of this operator
should translate the text matrix before the next showing of text.
Previously, this calculation was slightly wrong and also only applied
after the text was already shown.
This commit is contained in:
Julian Offenhäuser 2022-08-19 09:02:46 +02:00 • committed by Sam Atkins
parent 563d91b6c4
commit 97ed4106e5
2 changed files with 6 additions and 5 deletions
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8
Userland/Libraries/LibPDF/Renderer.cpp
View file

@ -453,8 +453,10 @@ RENDERER_HANDLER(text_show_string_array)
} else if (element.has<float>()) { } else if (element.has<float>()) {
next_shift = element.get<float>(); next_shift = element.get<float>();
} else { } else {
auto shift = next_shift / 1000.0f;
m_text_matrix.translate(-shift * text_state().font_size * text_state().horizontal_scaling, 0.0f);
auto str = element.get<NonnullRefPtr<Object>>()->cast<StringObject>()->string(); auto str = element.get<NonnullRefPtr<Object>>()->cast<StringObject>()->string();
show_text(str, next_shift); show_text(str);
} }
} }
@ -637,7 +639,7 @@ PDFErrorOr<void> Renderer::set_graphics_state_from_dict(NonnullRefPtr<DictObject
return {}; return {};
} }
void Renderer::show_text(String const& string, float shift) void Renderer::show_text(String const& string)
{ {
auto& text_rendering_matrix = calculate_text_rendering_matrix(); auto& text_rendering_matrix = calculate_text_rendering_matrix();
@ -660,7 +662,7 @@ void Renderer::show_text(String const& string, float shift)
m_painter.draw_glyph(glyph_position.to_type<int>(), code_point, *font, state().paint_color); m_painter.draw_glyph(glyph_position.to_type<int>(), code_point, *font, state().paint_color);
auto glyph_width = char_width * font_size; auto glyph_width = char_width * font_size;
auto tx = (glyph_width - shift / 1000.0f); auto tx = glyph_width;
tx += text_state().character_spacing; tx += text_state().character_spacing;
if (code_point == ' ') if (code_point == ' ')

3
Userland/Libraries/LibPDF/Renderer.h
View file

@ -98,8 +98,7 @@ private:
PDFErrorOr<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);
PDFErrorOr<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 operator array void show_text(String const&);
void show_text(String const&, float shift = 0.0f);
PDFErrorOr<NonnullRefPtr<ColorSpace>> get_color_space(Value const&); PDFErrorOr<NonnullRefPtr<ColorSpace>> get_color_space(Value const&);
ALWAYS_INLINE GraphicsState const& state() const { return m_graphics_state_stack.last(); } ALWAYS_INLINE GraphicsState const& state() const { return m_graphics_state_stack.last(); }