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LibPDF: Use Gfx::PathRasterizer for Adobe Type 1 font rendering

This gives much better visual results than painting the path directly.
It also has the nice side effect that Type 1 fonts will now look much
more similar to TrueType fonts, which use the same class :^)

In addition, we can now cache glyph bitmaps for repeated use.
This commit is contained in:
Julian Offenhäuser 2022-11-17 23:18:00 +01:00 committed by Andreas Kling
parent 0b6299849e
commit 7c4f5b58be
4 changed files with 69 additions and 11 deletions

View file

@ -4,6 +4,7 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibGfx/Font/PathRasterizer.h>
#include <LibPDF/CommonNames.h>
#include <LibPDF/Encoding.h>
#include <LibPDF/Fonts/PS1FontProgram.h>
@ -86,20 +87,61 @@ PDFErrorOr<void> PS1FontProgram::parse(ReadonlyBytes const& bytes, size_t cleart
return parse_encrypted_portion(decrypted);
}
Gfx::Path PS1FontProgram::build_char(u32 code_point, Gfx::FloatPoint const& point, float width)
RefPtr<Gfx::Bitmap> PS1FontProgram::rasterize_glyph(u32 code_point, float width)
{
if (!m_glyph_map.contains(code_point))
auto path = build_char(code_point, width);
auto bounding_box = path.bounding_box().size();
u32 w = (u32)ceilf(bounding_box.width()) + 1;
u32 h = (u32)ceilf(bounding_box.height()) + 1;
Gfx::PathRasterizer rasterizer(Gfx::IntSize(w, h));
rasterizer.draw_path(path);
return rasterizer.accumulate();
}
Gfx::Path PS1FontProgram::build_char(u32 code_point, float width)
{
auto maybe_glyph = m_glyph_map.get(code_point);
if (!maybe_glyph.has_value())
return {};
auto glyph = m_glyph_map.get(code_point).value();
auto& glyph = maybe_glyph.value();
auto transform = glyph_transform_to_device_space(glyph, width);
// Translate such that the top-left point is at [0, 0].
auto bounding_box = glyph.path.bounding_box();
Gfx::FloatPoint translation(-bounding_box.x(), -(bounding_box.y() + bounding_box.height()));
transform.translate(translation);
return glyph.path.copy_transformed(transform);
}
Gfx::FloatPoint PS1FontProgram::glyph_translation(u32 code_point, float width) const
{
auto maybe_glyph = m_glyph_map.get(code_point);
if (!maybe_glyph.has_value())
return {};
auto& glyph = maybe_glyph.value();
auto transform = glyph_transform_to_device_space(glyph, width);
// Undo the translation we applied earlier.
auto bounding_box = glyph.path.bounding_box();
Gfx::FloatPoint translation(bounding_box.x(), bounding_box.y() + bounding_box.height());
return transform.map(translation);
}
Gfx::AffineTransform PS1FontProgram::glyph_transform_to_device_space(Glyph const& glyph, float width) const
{
auto scale = width / (m_font_matrix.a() * glyph.width + m_font_matrix.e());
auto transform = m_font_matrix;
// Convert character space to device space.
transform.scale(scale, -scale);
transform.set_translation(point);
return glyph.path.copy_transformed(transform);
return transform;
}
PDFErrorOr<PS1FontProgram::Glyph> PS1FontProgram::parse_glyph(ReadonlyBytes const& data, GlyphParserState& state)

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@ -20,9 +20,11 @@ class PS1FontProgram : public RefCounted<PS1FontProgram> {
public:
PDFErrorOr<void> parse(ReadonlyBytes const&, size_t cleartext_length, size_t encrypted_length);
Gfx::Path build_char(u32 code_point, Gfx::FloatPoint const& point, float width);
RefPtr<Gfx::Bitmap> rasterize_glyph(u32 code_point, float width);
Gfx::Path build_char(u32 code_point, float width);
RefPtr<Encoding> encoding() const { return m_encoding; }
Gfx::FloatPoint glyph_translation(u32 code_point, float width) const;
private:
struct Glyph {
@ -46,6 +48,8 @@ private:
Array<float, 24> postscript_stack;
};
Gfx::AffineTransform glyph_transform_to_device_space(Glyph const&, float width) const;
PDFErrorOr<Glyph> parse_glyph(ReadonlyBytes const&, GlyphParserState&);
PDFErrorOr<void> parse_encrypted_portion(ByteBuffer const&);
PDFErrorOr<Vector<ByteBuffer>> parse_subroutines(Reader&);

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@ -122,11 +122,22 @@ float Type1Font::get_char_width(u16 char_code, float) const
void Type1Font::draw_glyph(Gfx::Painter& painter, Gfx::IntPoint const& point, float width, u32 code_point, Color color)
{
// FIXME: Make a glyph cache
if (m_data.font_program) {
auto path = m_data.font_program->build_char(code_point, { point.x(), point.y() }, width);
Gfx::AntiAliasingPainter aa_painter(painter);
aa_painter.fill_path(path, color, Gfx::Painter::WindingRule::EvenOdd);
if (!m_data.font_program)
return;
RefPtr<Gfx::Bitmap> bitmap;
auto maybe_bitmap = m_glyph_cache.get(code_point);
if (maybe_bitmap.has_value()) {
bitmap = maybe_bitmap.value();
} else {
bitmap = m_data.font_program->rasterize_glyph(code_point, width);
m_glyph_cache.set(code_point, bitmap);
}
auto translation = m_data.font_program->glyph_translation(code_point, width);
painter.blit_filtered(point.translated(translation.to_rounded<int>()), *bitmap, bitmap->rect(), [color](Color pixel) -> Color {
return pixel.multiply(color);
});
}
}

View file

@ -40,6 +40,7 @@ public:
private:
Data m_data;
HashMap<u32, RefPtr<Gfx::Bitmap>> m_glyph_cache;
};
}