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LibTTF: Split up Font.h into smaller internal header files.

This commit is contained in:
Srimanta Barua 2020-06-14 12:02:19 +05:30 committed by Andreas Kling
parent 1e1d2cdedf
commit ec08e9e780
7 changed files with 553 additions and 426 deletions

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@ -26,16 +26,13 @@
#pragma once
#include "Cmap.h"
#include <AK/ByteBuffer.h>
#include <AK/FixedArray.h>
#include <AK/Noncopyable.h>
#include <AK/Optional.h>
#include <AK/RefCounted.h>
#include <AK/StringView.h>
#include <LibGfx/AffineTransform.h>
#include <LibGfx/Bitmap.h>
#include <LibGfx/Size.h>
#include <math.h>
#define POINTS_PER_INCH 72.0f
#define DEFAULT_DPI 96
@ -85,376 +82,20 @@ private:
ScaledFontMetrics metrics(float x_scale, float y_scale) const;
ScaledGlyphMetrics glyph_metrics(u32 glyph_id, float x_scale, float y_scale) const;
RefPtr<Gfx::Bitmap> raster_glyph(u32 glyph_id, float x_scale, float y_scale) const;
u32 glyph_count() const { return m_maxp.num_glyphs(); }
class Rasterizer {
public:
Rasterizer(Gfx::IntSize);
void draw_path(Gfx::Path&);
RefPtr<Gfx::Bitmap> accumulate();
private:
void draw_line(Gfx::FloatPoint, Gfx::FloatPoint);
Gfx::IntSize m_size;
FixedArray<float> m_data;
};
enum class IndexToLocFormat {
Offset16,
Offset32,
};
class Head {
public:
Head() {}
Head(const ByteBuffer& slice)
: m_slice(slice)
{
ASSERT(m_slice.size() >= (size_t) Sizes::Table);
}
u16 units_per_em() const;
i16 xmin() const;
i16 ymin() const;
i16 xmax() const;
i16 ymax() const;
u16 lowest_recommended_ppem() const;
IndexToLocFormat index_to_loc_format() const;
private:
enum class Offsets {
UnitsPerEM = 18,
XMin = 36,
YMin = 38,
XMax = 40,
YMax = 42,
LowestRecPPEM = 46,
IndexToLocFormat = 50,
};
enum class Sizes {
Table = 54,
};
ByteBuffer m_slice;
};
class Hhea {
public:
Hhea() {}
Hhea(const ByteBuffer& slice)
: m_slice(slice)
{
ASSERT(m_slice.size() >= (size_t) Sizes::Table);
}
i16 ascender() const;
i16 descender() const;
i16 line_gap() const;
u16 advance_width_max() const;
u16 number_of_h_metrics() const;
private:
enum class Offsets {
Ascender = 4,
Descender = 6,
LineGap = 8,
AdvanceWidthMax = 10,
NumberOfHMetrics = 34,
};
enum class Sizes {
Table = 36,
};
ByteBuffer m_slice;
};
class Maxp {
public:
Maxp() {}
Maxp(const ByteBuffer& slice)
: m_slice(slice)
{
ASSERT(m_slice.size() >= (size_t) Sizes::TableV0p5);
}
u16 num_glyphs() const;
private:
enum class Offsets {
NumGlyphs = 4
};
enum class Sizes {
TableV0p5 = 6,
};
ByteBuffer m_slice;
};
struct GlyphHorizontalMetrics {
u16 advance_width;
i16 left_side_bearing;
};
class Hmtx {
public:
Hmtx() {}
Hmtx(const ByteBuffer& slice, u32 num_glyphs, u32 number_of_h_metrics)
: m_slice(slice)
, m_num_glyphs(num_glyphs)
, m_number_of_h_metrics(number_of_h_metrics)
{
ASSERT(m_slice.size() >= number_of_h_metrics * (u32) Sizes::LongHorMetric + (num_glyphs - number_of_h_metrics) * (u32) Sizes::LeftSideBearing);
}
GlyphHorizontalMetrics get_glyph_horizontal_metrics(u32 glyph_id) const;
private:
enum class Sizes {
LongHorMetric = 4,
LeftSideBearing = 2
};
ByteBuffer m_slice;
u32 m_num_glyphs;
u32 m_number_of_h_metrics;
};
class Cmap {
public:
class Subtable {
public:
enum class Platform {
Unicode = 0,
Macintosh = 1,
Windows = 3,
Custom = 4,
};
enum class Format {
ByteEncoding = 0,
HighByte = 2,
SegmentToDelta = 4,
TrimmedTable = 6,
Mixed16And32 = 8,
TrimmedArray = 10,
SegmentedCoverage = 12,
ManyToOneRange = 13,
UnicodeVariationSequences = 14,
};
enum class WindowsEncoding {
UnicodeBMP = 1,
UnicodeFullRepertoire = 10,
};
Subtable(const ByteBuffer& slice, u16 platform_id, u16 encoding_id)
: m_slice(slice)
, m_raw_platform_id(platform_id)
, m_encoding_id(encoding_id)
{
}
// Returns 0 if glyph not found. This corresponds to the "missing glyph"
u32 glyph_id_for_codepoint(u32 codepoint) const;
Platform platform_id() const;
u16 encoding_id() const { return m_encoding_id; }
Format format() const;
private:
enum class Table4Offsets {
SegCountX2 = 6,
EndConstBase = 14,
StartConstBase = 16,
DeltaConstBase = 16,
RangeConstBase = 16,
GlyphOffsetConstBase = 16,
};
enum class Table4Sizes {
Constant = 16,
NonConstMultiplier = 4,
};
enum class Table12Offsets {
NumGroups = 12,
Record_StartCode = 16,
Record_EndCode = 20,
Record_StartGlyph = 24,
};
enum class Table12Sizes {
Header = 16,
Record = 12,
};
u32 glyph_id_for_codepoint_table_4(u32 codepoint) const;
u32 glyph_id_for_codepoint_table_12(u32 codepoint) const;
ByteBuffer m_slice;
u16 m_raw_platform_id;
u16 m_encoding_id;
};
Cmap() {}
Cmap(const ByteBuffer& slice)
: m_slice(slice)
{
ASSERT(m_slice.size() > (size_t) Sizes::TableHeader);
}
u32 num_subtables() const;
Optional<Subtable> subtable(u32 index) const;
void set_active_index(u32 index) { m_active_index = index; }
// Returns 0 if glyph not found. This corresponds to the "missing glyph"
u32 glyph_id_for_codepoint(u32 codepoint) const;
private:
enum class Offsets {
NumTables = 2,
EncodingRecord_EncodingID = 2,
EncodingRecord_Offset = 4,
};
enum class Sizes {
TableHeader = 4,
EncodingRecord = 8,
};
ByteBuffer m_slice;
u32 m_active_index { UINT32_MAX };
};
class Loca {
public:
Loca() {}
Loca(const ByteBuffer& slice, u32 num_glyphs, IndexToLocFormat index_to_loc_format)
: m_slice(slice)
, m_num_glyphs(num_glyphs)
, m_index_to_loc_format(index_to_loc_format)
{
switch (m_index_to_loc_format) {
case IndexToLocFormat::Offset16:
ASSERT(m_slice.size() >= m_num_glyphs * 2);
break;
case IndexToLocFormat::Offset32:
ASSERT(m_slice.size() >= m_num_glyphs * 4);
break;
}
}
u32 get_glyph_offset(u32 glyph_id) const;
private:
ByteBuffer m_slice;
u32 m_num_glyphs;
IndexToLocFormat m_index_to_loc_format;
};
class Glyf {
public:
class Glyph {
public:
Glyph(const ByteBuffer& slice, i16 xmin, i16 ymin, i16 xmax, i16 ymax, i16 num_contours = -1)
: m_xmin(xmin)
, m_ymin(ymin)
, m_xmax(xmax)
, m_ymax(ymax)
, m_num_contours(num_contours)
, m_slice(move(slice))
{
if (m_num_contours >= 0) {
m_type = Type::Simple;
}
}
template <typename GlyphCb>
RefPtr<Gfx::Bitmap> raster(float x_scale, float y_scale, GlyphCb glyph_callback) const
{
switch (m_type) {
case Type::Simple:
return raster_simple(x_scale, y_scale);
case Type::Composite:
return raster_composite(x_scale, y_scale, glyph_callback);
}
ASSERT_NOT_REACHED();
}
int ascender() const { return m_ymax; }
int descender() const { return m_ymin; }
private:
enum class Type {
Simple,
Composite,
};
class ComponentIterator {
public:
struct Item {
u16 glyph_id;
Gfx::AffineTransform affine;
};
ComponentIterator(const ByteBuffer& slice)
: m_slice(slice)
{
}
Optional<Item> next();
private:
ByteBuffer m_slice;
bool m_has_more { true };
u32 m_offset { 0 };
};
void raster_inner(Rasterizer&, Gfx::AffineTransform&) const;
RefPtr<Gfx::Bitmap> raster_simple(float x_scale, float y_scale) const;
template <typename GlyphCb>
RefPtr<Gfx::Bitmap> raster_composite(float x_scale, float y_scale, GlyphCb glyph_callback) const
{
u32 width = (u32) (ceil((m_xmax - m_xmin) * x_scale)) + 1;
u32 height = (u32) (ceil((m_ymax - m_ymin) * y_scale)) + 1;
Rasterizer rasterizer(Gfx::IntSize(width, height));
auto affine = Gfx::AffineTransform().scale(x_scale, -y_scale).translate(-m_xmin, -m_ymax);
ComponentIterator component_iterator(m_slice);
while (true) {
auto opt_item = component_iterator.next();
if (!opt_item.has_value()) {
break;
}
auto item = opt_item.value();
auto affine_here = affine * item.affine;
auto glyph = glyph_callback(item.glyph_id);
glyph.raster_inner(rasterizer, affine_here);
}
return rasterizer.accumulate();
}
Type m_type { Type::Composite };
i16 m_xmin;
i16 m_ymin;
i16 m_xmax;
i16 m_ymax;
i16 m_num_contours { -1 };
ByteBuffer m_slice;
};
Glyf() {}
Glyf(const ByteBuffer& slice)
: m_slice(move(slice))
{
}
Glyph glyph(u32 offset) const;
private:
enum class Offsets {
XMin = 2,
YMin = 4,
XMax = 6,
YMax = 8,
};
enum class Sizes {
GlyphHeader = 10,
};
ByteBuffer m_slice;
};
u32 glyph_count() const;
u16 units_per_em() const;
// This owns the font data
ByteBuffer m_buffer;
Head m_head;
Hhea m_hhea;
Maxp m_maxp;
Hmtx m_hmtx;
// These are all non-owning slices
ByteBuffer m_head_slice;
ByteBuffer m_hhea_slice;
ByteBuffer m_maxp_slice;
ByteBuffer m_hmtx_slice;
ByteBuffer m_loca_slice;
ByteBuffer m_glyf_slice;
// These are stateful wrappers around tables
Cmap m_cmap;
Loca m_loca;
Glyf m_glyf;
friend ScaledFont;
};
@ -464,7 +105,7 @@ public:
ScaledFont(RefPtr<Font> font, float point_width, float point_height, unsigned dpi_x = DEFAULT_DPI, unsigned dpi_y = DEFAULT_DPI)
: m_font(font)
{
float units_per_em = m_font->m_head.units_per_em();
float units_per_em = m_font->units_per_em();
m_x_scale = (point_width * dpi_x) / (POINTS_PER_INCH * units_per_em);
m_y_scale = (point_height * dpi_y) / (POINTS_PER_INCH * units_per_em);
}