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LibPDF: Add new Type1FontProgram base class

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We are planning to add support for CFF fonts to read Type1 fonts, and
therefore much of the logic already found in PS1FontProgram will be
useful for representing the Type1 fonts read from CFF.

This commit moves the PS1-independent bits of PS1FontProgram into a new
Type1FontProgram base class that can be used as the base for CFF-based
Type1 fonts in the future. The Type1Font class uses this new type now
instead of storing a PS1FontProgram pointer. While doing this
refactoring I also took care of making some minor adjustments to the
PS1FontProgram API, namely:

 * Its create() method is static and returns a
   NonnullRefPtr<Type1FontProgram>.
 * Many (all?) of the parse_* methods are now static.
 * Added const where possible.

Notably, the Type1FontProgram also contains at the moment the code that
parses the CharString data from the PS1 program. This logic is very
similar in CFF files, so after some minor adjustments later on it should
be possible to reuse most of it.
This commit is contained in:
Rodrigo Tobar 2023-01-07 12:21:25 +08:00 • committed by Andreas Kling
parent e751ec2089
commit 416585f75a
7 changed files with 535 additions and 476 deletions
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1
Userland/Libraries/LibPDF/CMakeLists.txt
View file

@ -11,6 +11,7 @@ set(SOURCES
Fonts/TrueTypeFont.cpp
Fonts/Type0Font.cpp
Fonts/Type1Font.cpp
Fonts/Type1FontProgram.cpp
Interpolation.cpp
ObjectDerivatives.cpp
Parser.cpp

434
Userland/Libraries/LibPDF/Fonts/PS1FontProgram.cpp
View file

@ -14,38 +14,7 @@
namespace PDF {
enum Command {
HStem = 1,
VStem = 3,
VMoveTo,
RLineTo,
HLineTo,
VLineTo,
RRCurveTo,
ClosePath,
CallSubr,
Return,
Extended,
HSbW,
EndChar,
RMoveTo = 21,
HMoveTo,
VHCurveTo = 30,
HVCurveTo
};
enum ExtendedCommand {
DotSection,
VStem3,
HStem3,
Seac = 6,
Div = 12,
CallOtherSubr = 16,
Pop,
SetCurrentPoint = 33,
};
PDFErrorOr<void> PS1FontProgram::create(ReadonlyBytes const& bytes, RefPtr<Encoding> encoding, size_t cleartext_length, size_t encrypted_length)
PDFErrorOr<NonnullRefPtr<Type1FontProgram>> PS1FontProgram::create(ReadonlyBytes const& bytes, RefPtr<Encoding> encoding, size_t cleartext_length, size_t encrypted_length)
{
Reader reader(bytes);
if (reader.remaining() == 0)
@ -58,13 +27,14 @@ PDFErrorOr<void> PS1FontProgram::create(ReadonlyBytes const& bytes, RefPtr<Encod
if (!seek_name(reader, CommonNames::Encoding))
return error("Missing encoding array");
auto font_program = adopt_ref(*new PS1FontProgram());
if (encoding) {
// 9.6.6.2 Encodings for Type 1 Fonts:
// An Encoding entry may override a Type 1 font’s mapping from character codes to character names.
m_encoding = encoding;
font_program->set_encoding(move(encoding));
} else {
if (TRY(parse_word(reader)) == "StandardEncoding") {
m_encoding = Encoding::standard_encoding();
font_program->set_encoding(Encoding::standard_encoding());
} else {
HashMap<u16, CharDescriptor> descriptors;
@ -78,385 +48,21 @@ PDFErrorOr<void> PS1FontProgram::create(ReadonlyBytes const& bytes, RefPtr<Encod
descriptors.set(char_code, { name.starts_with('/') ? name.substring_view(1) : name.view(), char_code });
}
}
m_encoding = TRY(Encoding::create(descriptors));
font_program->set_encoding(TRY(Encoding::create(descriptors)));
}
}
bool found_font_matrix = seek_name(reader, "FontMatrix");
if (found_font_matrix) {
auto array = TRY(parse_number_array(reader, 6));
m_font_matrix = { array[0], array[1], array[2], array[3], array[4], array[5] };
font_program->set_font_matrix({ array[0], array[1], array[2], array[3], array[4], array[5] });
} else {
m_font_matrix = { 0.001f, 0.0f, 0.0f, 0.001f, 0.0f, 0.0f };
font_program->set_font_matrix({ 0.001f, 0.0f, 0.0f, 0.001f, 0.0f, 0.0f });
}
auto decrypted = TRY(decrypt(reader.bytes().slice(cleartext_length, encrypted_length), 55665, 4));
return parse_encrypted_portion(decrypted);
}
RefPtr<Gfx::Bitmap> PS1FontProgram::rasterize_glyph(u32 char_code, float width, Gfx::GlyphSubpixelOffset subpixel_offset)
{
auto path = build_char(char_code, width, subpixel_offset);
auto bounding_box = path.bounding_box().size();
u32 w = (u32)ceilf(bounding_box.width()) + 2;
u32 h = (u32)ceilf(bounding_box.height()) + 2;
Gfx::PathRasterizer rasterizer(Gfx::IntSize(w, h));
rasterizer.draw_path(path);
return rasterizer.accumulate();
}
Gfx::Path PS1FontProgram::build_char(u32 char_code, float width, Gfx::GlyphSubpixelOffset subpixel_offset)
{
auto maybe_glyph = m_glyph_map.get(char_code);
if (!maybe_glyph.has_value())
return {};
auto& glyph = maybe_glyph.value();
auto transform = Gfx::AffineTransform()
.translate(subpixel_offset.to_float_point())
.multiply(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 char_code, float width) const
{
auto maybe_glyph = m_glyph_map.get(char_code);
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);
return transform;
}
PDFErrorOr<PS1FontProgram::Glyph> PS1FontProgram::parse_glyph(ReadonlyBytes const& data, GlyphParserState& state)
{
auto push = [&](float value) -> PDFErrorOr<void> {
if (state.sp >= state.stack.size())
return error("Operand stack overflow");
state.stack[state.sp++] = value;
return {};
};
auto pop = [&]() -> float {
return state.sp ? state.stack[--state.sp] : 0.0f;
};
auto& path = state.glyph.path;
// Parse the stream of parameters and commands that make up a glyph outline.
for (size_t i = 0; i < data.size(); ++i) {
auto require = [&](unsigned num) -> PDFErrorOr<void> {
if (i + num >= data.size())
return error("Malformed glyph outline definition");
return {};
};
int v = data[i];
if (v == 255) {
TRY(require(4));
int a = data[++i];
int b = data[++i];
int c = data[++i];
int d = data[++i];
TRY(push((a << 24) + (b << 16) + (c << 8) + d));
} else if (v >= 251) {
TRY(require(1));
auto w = data[++i];
TRY(push(-((v - 251) * 256) - w - 108));
} else if (v >= 247) {
TRY(require(1));
auto w = data[++i];
TRY(push(((v - 247) * 256) + w + 108));
} else if (v >= 32) {
TRY(push(v - 139));
} else {
// Not a parameter but a command byte.
switch (v) {
case HStem:
case VStem:
state.sp = 0;
break;
case VMoveTo: {
auto dy = pop();
state.point.translate_by(0.0f, dy);
if (state.flex_feature) {
state.flex_sequence[state.flex_index++] = state.point.x();
state.flex_sequence[state.flex_index++] = state.point.y();
} else {
path.move_to(state.point);
}
state.sp = 0;
break;
}
case RLineTo: {
auto dy = pop();
auto dx = pop();
state.point.translate_by(dx, dy);
path.line_to(state.point);
state.sp = 0;
break;
}
case HLineTo: {
auto dx = pop();
state.point.translate_by(dx, 0.0f);
path.line_to(state.point);
state.sp = 0;
break;
}
case VLineTo: {
auto dy = pop();
state.point.translate_by(0.0f, dy);
path.line_to(state.point);
state.sp = 0;
break;
}
case RRCurveTo: {
auto dy3 = pop();
auto dx3 = pop();
auto dy2 = pop();
auto dx2 = pop();
auto dy1 = pop();
auto dx1 = pop();
auto& point = state.point;
path.cubic_bezier_curve_to(
point + Gfx::FloatPoint(dx1, dy1),
point + Gfx::FloatPoint(dx1 + dx2, dy1 + dy2),
point + Gfx::FloatPoint(dx1 + dx2 + dx3, dy1 + dy2 + dy3));
point.translate_by(dx1 + dx2 + dx3, dy1 + dy2 + dy3);
state.sp = 0;
break;
}
case ClosePath:
path.close();
state.sp = 0;
break;
case CallSubr: {
auto subr_number = pop();
if (static_cast<size_t>(subr_number) >= m_subroutines.size())
return error("Subroutine index out of range");
// Subroutines 0-2 handle the flex feature.
if (subr_number == 0) {
if (state.flex_index != 14)
break;
auto& flex = state.flex_sequence;
path.cubic_bezier_curve_to(
{ flex[2], flex[3] },
{ flex[4], flex[5] },
{ flex[6], flex[7] });
path.cubic_bezier_curve_to(
{ flex[8], flex[9] },
{ flex[10], flex[11] },
{ flex[12], flex[13] });
state.flex_feature = false;
state.sp = 0;
} else if (subr_number == 1) {
state.flex_feature = true;
state.flex_index = 0;
state.sp = 0;
} else if (subr_number == 2) {
state.sp = 0;
} else {
auto subr = m_subroutines[subr_number];
if (subr.is_empty())
return error("Empty subroutine");
TRY(parse_glyph(subr, state));
}
break;
}
case Return:
break;
case Extended: {
TRY(require(1));
switch (data[++i]) {
case DotSection:
case VStem3:
case HStem3:
case Seac:
// FIXME: Do something with these?
state.sp = 0;
break;
case Div: {
auto num2 = pop();
auto num1 = pop();
TRY(push(num2 ? num1 / num2 : 0.0f));
break;
}
case CallOtherSubr: {
auto othersubr_number = pop();
auto n = static_cast<int>(pop());
if (othersubr_number == 0) {
state.postscript_stack[state.postscript_sp++] = pop();
state.postscript_stack[state.postscript_sp++] = pop();
pop();
} else if (othersubr_number == 3) {
state.postscript_stack[state.postscript_sp++] = 3;
} else {
for (int i = 0; i < n; ++i)
state.postscript_stack[state.postscript_sp++] = pop();
}
(void)othersubr_number;
break;
}
case Pop:
TRY(push(state.postscript_stack[--state.postscript_sp]));
break;
case SetCurrentPoint: {
auto y = pop();
auto x = pop();
state.point = { x, y };
path.move_to(state.point);
state.sp = 0;
break;
}
default:
return error(DeprecatedString::formatted("Unhandled command: 12 {}", data[i]));
}
break;
}
case HSbW: {
auto wx = pop();
auto sbx = pop();
state.glyph.width = wx;
state.point = { sbx, 0.0f };
state.sp = 0;
break;
}
case EndChar:
break;
case RMoveTo: {
auto dy = pop();
auto dx = pop();
state.point.translate_by(dx, dy);
if (state.flex_feature) {
state.flex_sequence[state.flex_index++] = state.point.x();
state.flex_sequence[state.flex_index++] = state.point.y();
} else {
path.move_to(state.point);
}
state.sp = 0;
break;
}
case HMoveTo: {
auto dx = pop();
state.point.translate_by(dx, 0.0f);
if (state.flex_feature) {
state.flex_sequence[state.flex_index++] = state.point.x();
state.flex_sequence[state.flex_index++] = state.point.y();
} else {
path.move_to(state.point);
}
state.sp = 0;
break;
}
case VHCurveTo: {
auto dx3 = pop();
auto dy2 = pop();
auto dx2 = pop();
auto dy1 = pop();
auto& point = state.point;
path.cubic_bezier_curve_to(
point + Gfx::FloatPoint(0.0f, dy1),
point + Gfx::FloatPoint(dx2, dy1 + dy2),
point + Gfx::FloatPoint(dx2 + dx3, dy1 + dy2));
point.translate_by(dx2 + dx3, dy1 + dy2);
state.sp = 0;
break;
}
case HVCurveTo: {
auto dy3 = pop();
auto dy2 = pop();
auto dx2 = pop();
auto dx1 = pop();
auto& point = state.point;
path.cubic_bezier_curve_to(
point + Gfx::FloatPoint(dx1, 0.0f),
point + Gfx::FloatPoint(dx1 + dx2, dy2),
point + Gfx::FloatPoint(dx1 + dx2, dy2 + dy3));
point.translate_by(dx1 + dx2, dy2 + dy3);
state.sp = 0;
break;
}
default:
return error(DeprecatedString::formatted("Unhandled command: {}", v));
}
}
}
return state.glyph;
TRY(font_program->parse_encrypted_portion(decrypted));
return font_program;
}
PDFErrorOr<void> PS1FontProgram::parse_encrypted_portion(ByteBuffer const& buffer)
@ -468,7 +74,7 @@ PDFErrorOr<void> PS1FontProgram::parse_encrypted_portion(ByteBuffer const& buffe
if (!seek_name(reader, "Subrs"))
return error("Missing subroutine array");
m_subroutines = TRY(parse_subroutines(reader));
auto subroutines = TRY(parse_subroutines(reader));
if (!seek_name(reader, "CharStrings"))
return error("Missing char strings array");
@ -486,10 +92,10 @@ PDFErrorOr<void> PS1FontProgram::parse_encrypted_portion(ByteBuffer const& buffe
if (rd == "-|" || rd == "RD") {
auto line = TRY(decrypt(reader.bytes().slice(reader.offset(), encrypted_size), m_encryption_key, m_lenIV));
reader.move_by(encrypted_size);
auto name_mapping = m_encoding->name_mapping();
auto name_mapping = encoding()->name_mapping();
auto char_code = name_mapping.ensure(word.substring_view(1));
GlyphParserState state;
m_glyph_map.set(char_code, TRY(parse_glyph(line, state)));
TRY(add_glyph(char_code, TRY(parse_glyph(line, subroutines, state))));
}
}
}
@ -497,7 +103,7 @@ PDFErrorOr<void> PS1FontProgram::parse_encrypted_portion(ByteBuffer const& buffe
return {};
}
PDFErrorOr<Vector<ByteBuffer>> PS1FontProgram::parse_subroutines(Reader& reader)
PDFErrorOr<Vector<ByteBuffer>> PS1FontProgram::parse_subroutines(Reader& reader) const
{
if (!reader.matches_number())
return error("Expected array length");
@ -634,18 +240,4 @@ bool PS1FontProgram::seek_name(Reader& reader, DeprecatedString const& name)
return false;
}
Error PS1FontProgram::error(
DeprecatedString const& message
#ifdef PDF_DEBUG
,
SourceLocation loc
#endif
)
{
#ifdef PDF_DEBUG
dbgln("\033[31m{} Type 1 font error: {}\033[0m", loc, message);
#endif
return Error { Error::Type::MalformedPDF, message };
}
}

61
Userland/Libraries/LibPDF/Fonts/PS1FontProgram.h
View file

@ -11,72 +11,31 @@
#include <LibGfx/Font/Font.h>
#include <LibGfx/Path.h>
#include <LibPDF/Error.h>
#include <LibPDF/Fonts/Type1FontProgram.h>
namespace PDF {
class Reader;
class Encoding;
class PS1FontProgram : public RefCounted<PS1FontProgram> {
class PS1FontProgram : public Type1FontProgram {
public:
PDFErrorOr<void> create(ReadonlyBytes const&, RefPtr<Encoding>, size_t cleartext_length, size_t encrypted_length);
RefPtr<Gfx::Bitmap> rasterize_glyph(u32 char_code, float width, Gfx::GlyphSubpixelOffset);
Gfx::Path build_char(u32 char_code, float width, Gfx::GlyphSubpixelOffset);
RefPtr<Encoding> encoding() const { return m_encoding; }
Gfx::FloatPoint glyph_translation(u32 char_code, float width) const;
static PDFErrorOr<NonnullRefPtr<Type1FontProgram>> create(ReadonlyBytes const&, RefPtr<Encoding>, size_t cleartext_length, size_t encrypted_length);
private:
struct Glyph {
Gfx::Path path;
float width;
};
struct GlyphParserState {
Glyph glyph;
Gfx::FloatPoint point;
bool flex_feature { false };
size_t flex_index;
Array<float, 14> flex_sequence;
size_t sp { 0 };
Array<float, 24> stack;
size_t postscript_sp { 0 };
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&);
PDFErrorOr<Vector<float>> parse_number_array(Reader&, size_t length);
PDFErrorOr<DeprecatedString> parse_word(Reader&);
PDFErrorOr<float> parse_float(Reader&);
PDFErrorOr<int> parse_int(Reader&);
PDFErrorOr<Vector<ByteBuffer>> parse_subroutines(Reader&) const;
static PDFErrorOr<Vector<float>> parse_number_array(Reader&, size_t length);
static PDFErrorOr<DeprecatedString> parse_word(Reader&);
static PDFErrorOr<float> parse_float(Reader&);
static PDFErrorOr<int> parse_int(Reader&);
PDFErrorOr<ByteBuffer> decrypt(ReadonlyBytes const&, u16 key, size_t skip);
bool seek_name(Reader&, DeprecatedString const&);
static PDFErrorOr<ByteBuffer> decrypt(ReadonlyBytes const&, u16 key, size_t skip);
static bool seek_name(Reader&, DeprecatedString const&);
static Error error(
DeprecatedString const& message
#ifdef PDF_DEBUG
,
SourceLocation loc = SourceLocation::current()
#endif
);
Vector<ByteBuffer> m_subroutines;
Vector<ByteBuffer> m_character_names;
HashMap<u16, Glyph> m_glyph_map;
Gfx::AffineTransform m_font_matrix;
RefPtr<Encoding> m_encoding;
u16 m_encryption_key { 4330 };
int m_lenIV { 4 };

4
Userland/Libraries/LibPDF/Fonts/Type1Font.cpp
View file

@ -7,6 +7,7 @@
#include <LibGfx/Painter.h>
#include <LibPDF/CommonNames.h>
#include <LibPDF/Fonts/PS1FontProgram.h>
#include <LibPDF/Fonts/Type1Font.h>
namespace PDF {
@ -30,8 +31,7 @@ PDFErrorOr<Type1Font::Data> Type1Font::parse_data(Document* document, NonnullRef
auto length1 = TRY(document->resolve(font_file_dict->get_value(CommonNames::Length1))).get<int>();
auto length2 = TRY(document->resolve(font_file_dict->get_value(CommonNames::Length2))).get<int>();
data.font_program = adopt_ref(*new PS1FontProgram());
TRY(data.font_program->create(font_file_stream->bytes(), data.encoding, length1, length2));
data.font_program = TRY(PS1FontProgram::create(font_file_stream->bytes(), data.encoding, length1, length2));
if (!data.encoding)
data.encoding = data.font_program->encoding();

4
Userland/Libraries/LibPDF/Fonts/Type1Font.h
View file

@ -8,14 +8,14 @@
#include <LibGfx/Font/ScaledFont.h>
#include <LibPDF/Fonts/PDFFont.h>
#include <LibPDF/Fonts/PS1FontProgram.h>
#include <LibPDF/Fonts/Type1FontProgram.h>
namespace PDF {
class Type1Font : public PDFFont {
public:
struct Data : PDFFont::CommonData {
RefPtr<PS1FontProgram> font_program;
RefPtr<Type1FontProgram> font_program;
};
static PDFErrorOr<Data> parse_data(Document*, NonnullRefPtr<DictObject> font_dict, float font_size);

423
Userland/Libraries/LibPDF/Fonts/Type1FontProgram.cpp Normal file
View file

@ -0,0 +1,423 @@
/*
* Copyright (c) 2023, Rodrigo Tobar <rtobarc@gmail.com>.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibGfx/Font/PathRasterizer.h>
#include <LibPDF/Fonts/Type1FontProgram.h>
namespace PDF {
enum Command {
HStem = 1,
VStem = 3,
VMoveTo,
RLineTo,
HLineTo,
VLineTo,
RRCurveTo,
ClosePath,
CallSubr,
Return,
Extended,
HSbW,
EndChar,
RMoveTo = 21,
HMoveTo,
VHCurveTo = 30,
HVCurveTo
};
enum ExtendedCommand {
DotSection,
VStem3,
HStem3,
Seac = 6,
Div = 12,
CallOtherSubr = 16,
Pop,
SetCurrentPoint = 33,
};
RefPtr<Gfx::Bitmap> Type1FontProgram::rasterize_glyph(u32 char_code, float width, Gfx::GlyphSubpixelOffset subpixel_offset)
{
auto path = build_char(char_code, width, subpixel_offset);
auto bounding_box = path.bounding_box().size();
u32 w = (u32)ceilf(bounding_box.width()) + 2;
u32 h = (u32)ceilf(bounding_box.height()) + 2;
Gfx::PathRasterizer rasterizer(Gfx::IntSize(w, h));
rasterizer.draw_path(path);
return rasterizer.accumulate();
}
Gfx::Path Type1FontProgram::build_char(u32 char_code, float width, Gfx::GlyphSubpixelOffset subpixel_offset)
{
auto maybe_glyph = m_glyph_map.get(char_code);
if (!maybe_glyph.has_value())
return {};
auto& glyph = maybe_glyph.value();
auto transform = Gfx::AffineTransform()
.translate(subpixel_offset.to_float_point())
.multiply(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 Type1FontProgram::glyph_translation(u32 char_code, float width) const
{
auto maybe_glyph = m_glyph_map.get(char_code);
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 Type1FontProgram::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);
return transform;
}
PDFErrorOr<Type1FontProgram::Glyph> Type1FontProgram::parse_glyph(ReadonlyBytes const& data, Vector<ByteBuffer> const& subroutines, GlyphParserState& state)
{
auto push = [&](float value) -> PDFErrorOr<void> {
if (state.sp >= state.stack.size())
return error("Operand stack overflow");
state.stack[state.sp++] = value;
return {};
};
auto pop = [&]() -> float {
return state.sp ? state.stack[--state.sp] : 0.0f;
};
auto& path = state.glyph.path;
// Parse the stream of parameters and commands that make up a glyph outline.
for (size_t i = 0; i < data.size(); ++i) {
auto require = [&](unsigned num) -> PDFErrorOr<void> {
if (i + num >= data.size())
return error("Malformed glyph outline definition");
return {};
};
int v = data[i];
if (v == 255) {
TRY(require(4));
int a = data[++i];
int b = data[++i];
int c = data[++i];
int d = data[++i];
TRY(push((a << 24) + (b << 16) + (c << 8) + d));
} else if (v >= 251) {
TRY(require(1));
auto w = data[++i];
TRY(push(-((v - 251) * 256) - w - 108));
} else if (v >= 247) {
TRY(require(1));
auto w = data[++i];
TRY(push(((v - 247) * 256) + w + 108));
} else if (v >= 32) {
TRY(push(v - 139));
} else {
// Not a parameter but a command byte.
switch (v) {
case HStem:
case VStem:
state.sp = 0;
break;
case VMoveTo: {
auto dy = pop();
state.point.translate_by(0.0f, dy);
if (state.flex_feature) {
state.flex_sequence[state.flex_index++] = state.point.x();
state.flex_sequence[state.flex_index++] = state.point.y();
} else {
path.move_to(state.point);
}
state.sp = 0;
break;
}
case RLineTo: {
auto dy = pop();
auto dx = pop();
state.point.translate_by(dx, dy);
path.line_to(state.point);
state.sp = 0;
break;
}
case HLineTo: {
auto dx = pop();
state.point.translate_by(dx, 0.0f);
path.line_to(state.point);
state.sp = 0;
break;
}
case VLineTo: {
auto dy = pop();
state.point.translate_by(0.0f, dy);
path.line_to(state.point);
state.sp = 0;
break;
}
case RRCurveTo: {
auto dy3 = pop();
auto dx3 = pop();
auto dy2 = pop();
auto dx2 = pop();
auto dy1 = pop();
auto dx1 = pop();
auto& point = state.point;
path.cubic_bezier_curve_to(
point + Gfx::FloatPoint(dx1, dy1),
point + Gfx::FloatPoint(dx1 + dx2, dy1 + dy2),
point + Gfx::FloatPoint(dx1 + dx2 + dx3, dy1 + dy2 + dy3));
point.translate_by(dx1 + dx2 + dx3, dy1 + dy2 + dy3);
state.sp = 0;
break;
}
case ClosePath:
path.close();
state.sp = 0;
break;
case CallSubr: {
auto subr_number = pop();
if (static_cast<size_t>(subr_number) >= subroutines.size())
return error("Subroutine index out of range");
// Subroutines 0-2 handle the flex feature.
if (subr_number == 0) {
if (state.flex_index != 14)
break;
auto& flex = state.flex_sequence;
path.cubic_bezier_curve_to(
{ flex[2], flex[3] },
{ flex[4], flex[5] },
{ flex[6], flex[7] });
path.cubic_bezier_curve_to(
{ flex[8], flex[9] },
{ flex[10], flex[11] },
{ flex[12], flex[13] });
state.flex_feature = false;
state.sp = 0;
} else if (subr_number == 1) {
state.flex_feature = true;
state.flex_index = 0;
state.sp = 0;
} else if (subr_number == 2) {
state.sp = 0;
} else {
auto subr = subroutines[subr_number];
if (subr.is_empty())
return error("Empty subroutine");
TRY(parse_glyph(subr, subroutines, state));
}
break;
}
case Return:
break;
case Extended: {
TRY(require(1));
switch (data[++i]) {
case DotSection:
case VStem3:
case HStem3:
case Seac:
// FIXME: Do something with these?
state.sp = 0;
break;
case Div: {
auto num2 = pop();
auto num1 = pop();
TRY(push(num2 ? num1 / num2 : 0.0f));
break;
}
case CallOtherSubr: {
auto othersubr_number = pop();
auto n = static_cast<int>(pop());
if (othersubr_number == 0) {
state.postscript_stack[state.postscript_sp++] = pop();
state.postscript_stack[state.postscript_sp++] = pop();
pop();
} else if (othersubr_number == 3) {
state.postscript_stack[state.postscript_sp++] = 3;
} else {
for (int i = 0; i < n; ++i)
state.postscript_stack[state.postscript_sp++] = pop();
}
(void)othersubr_number;
break;
}
case Pop:
TRY(push(state.postscript_stack[--state.postscript_sp]));
break;
case SetCurrentPoint: {
auto y = pop();
auto x = pop();
state.point = { x, y };
path.move_to(state.point);
state.sp = 0;
break;
}
default:
return error(DeprecatedString::formatted("Unhandled command: 12 {}", data[i]));
}
break;
}
case HSbW: {
auto wx = pop();
auto sbx = pop();
state.glyph.width = wx;
state.point = { sbx, 0.0f };
state.sp = 0;
break;
}
case EndChar:
break;
case RMoveTo: {
auto dy = pop();
auto dx = pop();
state.point.translate_by(dx, dy);
if (state.flex_feature) {
state.flex_sequence[state.flex_index++] = state.point.x();
state.flex_sequence[state.flex_index++] = state.point.y();
} else {
path.move_to(state.point);
}
state.sp = 0;
break;
}
case HMoveTo: {
auto dx = pop();
state.point.translate_by(dx, 0.0f);
if (state.flex_feature) {
state.flex_sequence[state.flex_index++] = state.point.x();
state.flex_sequence[state.flex_index++] = state.point.y();
} else {
path.move_to(state.point);
}
state.sp = 0;
break;
}
case VHCurveTo: {
auto dx3 = pop();
auto dy2 = pop();
auto dx2 = pop();
auto dy1 = pop();
auto& point = state.point;
path.cubic_bezier_curve_to(
point + Gfx::FloatPoint(0.0f, dy1),
point + Gfx::FloatPoint(dx2, dy1 + dy2),
point + Gfx::FloatPoint(dx2 + dx3, dy1 + dy2));
point.translate_by(dx2 + dx3, dy1 + dy2);
state.sp = 0;
break;
}
case HVCurveTo: {
auto dy3 = pop();
auto dy2 = pop();
auto dx2 = pop();
auto dx1 = pop();
auto& point = state.point;
path.cubic_bezier_curve_to(
point + Gfx::FloatPoint(dx1, 0.0f),
point + Gfx::FloatPoint(dx1 + dx2, dy2),
point + Gfx::FloatPoint(dx1 + dx2, dy2 + dy3));
point.translate_by(dx1 + dx2, dy2 + dy3);
state.sp = 0;
break;
}
default:
return error(DeprecatedString::formatted("Unhandled command: {}", v));
}
}
}
return state.glyph;
}
Error Type1FontProgram::error(
DeprecatedString const& message
#ifdef PDF_DEBUG
,
SourceLocation loc
#endif
)
{
#ifdef PDF_DEBUG
dbgln("\033[31m{} Type 1 font error: {}\033[0m", loc, message);
#endif
return Error { Error::Type::MalformedPDF, message };
}
}

84
Userland/Libraries/LibPDF/Fonts/Type1FontProgram.h Normal file
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@ -0,0 +1,84 @@
/*
* Copyright (c) 2023, Rodrigo Tobar <rtobarc@gmail.com>.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Debug.h>
#include <AK/SourceLocation.h>
#include <LibGfx/Font/Font.h>
#include <LibGfx/Path.h>
#include <LibPDF/Encoding.h>
#include <LibPDF/Error.h>
namespace PDF {
class Encoding;
class Type1FontProgram : public RefCounted<Type1FontProgram> {
public:
RefPtr<Gfx::Bitmap> rasterize_glyph(u32 char_code, float width, Gfx::GlyphSubpixelOffset subpixel_offset);
Gfx::FloatPoint glyph_translation(u32 char_code, float width) const;
RefPtr<Encoding> encoding() const { return m_encoding; }
protected:
struct Glyph {
Gfx::Path path;
float width;
};
struct GlyphParserState {
Glyph glyph;
Gfx::FloatPoint point;
bool flex_feature { false };
size_t flex_index;
Array<float, 14> flex_sequence;
size_t sp { 0 };
Array<float, 24> stack;
size_t postscript_sp { 0 };
Array<float, 24> postscript_stack;
};
static PDFErrorOr<Glyph> parse_glyph(ReadonlyBytes const&, Vector<ByteBuffer> const&, GlyphParserState&);
static Error error(
DeprecatedString const& message
#ifdef PDF_DEBUG
,
SourceLocation loc = SourceLocation::current()
#endif
);
void set_encoding(RefPtr<Encoding>&& encoding)
{
m_encoding = move(encoding);
}
void set_font_matrix(Gfx::AffineTransform&& font_matrix)
{
m_font_matrix = move(font_matrix);
}
PDFErrorOr<void> add_glyph(u16 char_code, Glyph&& glyph)
{
TRY(m_glyph_map.try_set(char_code, glyph));
return {};
}
private:
HashMap<u16, Glyph> m_glyph_map;
Gfx::AffineTransform m_font_matrix;
RefPtr<Encoding> m_encoding;
Gfx::Path build_char(u32 char_code, float width, Gfx::GlyphSubpixelOffset subpixel_offset);
Gfx::AffineTransform glyph_transform_to_device_space(Glyph const& glyph, float width) const;
};
}