Introduce distancefieldgenerator

A tool that allows you to pick prepare .qdf files which are pregenerated
distance fields in binary form that can be loaded by Qt to improve
startup time.

We currently only support cmaps subtable formats 0, 4, 6, 10 and 12,
as these are either A. the most commonly used (4 and 12) or B. simple
to implement.

The tool writes a .ttf file which is a copy of the original file,
but with the addition of a "qtdf" table that follows sfnt conventions.
This way, the file will work as a normal font file, as well, which
means that glyphs that are not in the pregenerated cache can easily
be generated at runtime.

Task-number: QTBUG-69356
Change-Id: Ib99c2d62f65e65973a60da4b1aa632b7ed3b2794
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 237 insertions, 0 deletions

diff --git a/src/distancefieldgenerator/distancefieldmodel.h b/src/distancefieldgenerator/distancefieldmodel.h
new file mode 100644
index 000000000..b866e5e6a
--- /dev/null
+++ b/src/distancefieldgenerator/distancefieldmodel.h
@@ -0,0 +1,237 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the tools applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef DISTANCEFIELDMODEL_H
+#define DISTANCEFIELDMODEL_H
+
+#include <QAbstractListModel>
+#include <QRawFont>
+#include <QtGui/private/qtextengine_p.h>
+#include <QMultiHash>
+#include <QScopedPointer>
+#include <QMetaEnum>
+#include <QThread>
+
+QT_BEGIN_NAMESPACE
+
+class QThread;
+class DistanceFieldModelWorker;
+class DistanceFieldModel : public QAbstractListModel
+{
+    Q_OBJECT
+public:
+    enum UnicodeRange {
+        Other                                = 0x00,
+        BasicLatin                           = 0x20,
+        Latin1Supplement                     = 0xa0,
+        LatinExtendedA                       = 0x100,
+        LatinExtendedB                       = 0x180,
+        IPAExtensions                        = 0x250,
+        SpacingModifierLetters               = 0x2b0,
+        CombiningDiacriticalMarks            = 0x300,
+        GreekAndCoptic                       = 0x370,
+        Cyrillic                             = 0x400,
+        CyrillicSupplementary                = 0x500,
+        Armenian                             = 0x530,
+        Hebrew                               = 0x590,
+        Arabic                               = 0x600,
+        Syriac                               = 0x700,
+        Thaana                               = 0x780,
+        Devanagari                           = 0x900,
+        Bengali                              = 0x980,
+        Gurmukhi                             = 0xa00,
+        Gujarati                             = 0xa80,
+        Oriya                                = 0xb00,
+        Tamil                                = 0xb80,
+        Telugu                               = 0xc00,
+        Kannada                              = 0xc80,
+        Malayalam                            = 0xd00,
+        Sinhala                              = 0xd80,
+        Thai                                 = 0xe00,
+        Lao                                  = 0xe80,
+        Tibetan                              = 0xf00,
+        Myanmar                              = 0x1000,
+        Georgian                             = 0x10a0,
+        HangulJamo                           = 0x1100,
+        Ethiopic                             = 0x1200,
+        Cherokee                             = 0x13a0,
+        UnifiedCanadianAboriginalSyllabics   = 0x1400,
+        Ogham                                = 0x1680,
+        Runic                                = 0x16a0,
+        Tagalog                              = 0x1700,
+        Hanunoo                              = 0x1720,
+        Buhid                                = 0x1740,
+        Tagbanwa                             = 0x1760,
+        Khmer                                = 0x1780,
+        Mongolian                            = 0x1800,
+        Limbu                                = 0x1900,
+        TaiLe                                = 0x1950,
+        KhmerSymbols                         = 0x19e0,
+        PhoneticExtensions                   = 0x1d00,
+        LatinExtendedAdditional              = 0x1e00,
+        GreekExtended                        = 0x1f00,
+        GeneralPunctuation                   = 0x2000,
+        SuperscriptsAndSubscripts            = 0x2070,
+        CurrencySymbols                      = 0x20a0,
+        CombiningDiacriticalMarksForSymbols  = 0x20d0,
+        LetterlikeSymbols                    = 0x2100,
+        NumberForms                          = 0x2150,
+        Arrows                               = 0x2190,
+        MathematicalOperators                = 0x2200,
+        MiscellaneousTechnical               = 0x2300,
+        ControlPictures                      = 0x2400,
+        OpticalCharacterRecognition          = 0x2440,
+        EnclosedAlphanumerics                = 0x2460,
+        BoxDrawing                           = 0x2500,
+        BlockElements                        = 0x2580,
+        GeometricShapes                      = 0x25a0,
+        MiscellaneousSymbols                 = 0x2600,
+        Dingbats                             = 0x2700,
+        MiscellaneousMathematicalSymbolsA    = 0x27c0,
+        SupplementalArrowsA                  = 0x27f0,
+        BraillePatterns                      = 0x2800,
+        SupplementalArrowsB                  = 0x2900,
+        MiscellaneousMathematicalSymbolsB    = 0x2980,
+        SupplementalMathematicalOperators    = 0x2a00,
+        MiscellaneousSymbolsAndArrows        = 0x2b00,
+        CJKRadicalsSupplement                = 0x2e80,
+        KangxiRadicals                       = 0x2f00,
+        IdeographicDescriptionCharacters     = 0x2ff0,
+        CJKSymbolsAndPunctuation             = 0x3000,
+        Hiragana                             = 0x3040,
+        Katakana                             = 0x30a0,
+        Bopomofo                             = 0x3100,
+        HangulCompatibilityJamo              = 0x3130,
+        Kanbun                               = 0x3190,
+        BopomofoExtended                     = 0x31a0,
+        KatakanaPhoneticExtensions           = 0x31f0,
+        EnclosedCJKLettersAndMonths          = 0x3200,
+        CJKCompatibility                     = 0x3300,
+        CJKUnifiedIdeographsExtensionA       = 0x3400,
+        YijingHexagramSymbols                = 0x4dc0,
+        CJKUnifiedIdeographs                 = 0x4e00,
+        YiSyllables                          = 0xa000,
+        YiRadicals                           = 0xa490,
+        HangulSyllables                      = 0xac00,
+        HighSurrogates                       = 0xd800,
+        HighPrivateUseSurrogates             = 0xdb80,
+        LowSurrogates                        = 0xdc00,
+        PrivateUseArea                       = 0xe000,
+        CJKCompatibilityIdeographs           = 0xf900,
+        AlphabeticPresentationForms          = 0xfb00,
+        ArabicPresentationFormsA             = 0xfb50,
+        VariationSelectors                   = 0xfe00,
+        CombiningHalfMarks                   = 0xfe20,
+        CJKCompatibilityForms                = 0xfe30,
+        SmallFormVariants                    = 0xfe50,
+        ArabicPresentationFormsB             = 0xfe70,
+        HalfwidthAndFullwidthForms           = 0xff00,
+        Specials                             = 0xfff0,
+        LinearBSyllabary                     = 0x10000,
+        LinearBIdeograms                     = 0x10080,
+        AegeanNumbers                        = 0x10100,
+        OldItalic                            = 0x10300,
+        Gothic                               = 0x10330,
+        Ugaritic                             = 0x10380,
+        Deseret                              = 0x10400,
+        Shavian                              = 0x10450,
+        Osmanya                              = 0x10480,
+        CypriotSyllabary                     = 0x10800,
+        ByzantineMusicalSymbols              = 0x1d000,
+        MusicalSymbols                       = 0x1d100,
+        TaiXuanJingSymbols                   = 0x1d300,
+        MathematicalAlphanumericSymbols      = 0x1d400,
+        CJKUnifiedIdeographsExtensionB       = 0x20000,
+        CJKCompatibilityIdeographsSupplement = 0x2f800,
+        Tags                                 = 0xe0000,
+        End                                  = 0xe007f
+    };
+    Q_ENUM(UnicodeRange)
+
+    explicit DistanceFieldModel(QObject *parent = nullptr);
+    ~DistanceFieldModel() override;
+
+    QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override;
+
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
+    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
+
+    void setFont(const QString &fileName);
+
+    QList<UnicodeRange> unicodeRanges() const;
+    QList<glyph_t> glyphIndexesForUnicodeRange(UnicodeRange range) const;
+    QString nameForUnicodeRange(UnicodeRange range) const;
+    glyph_t glyphIndexForUcs4(quint32 ucs4) const;
+
+    QImage distanceField(int row) const
+    {
+        return m_distanceFields.at(row);
+    }
+
+    QPainterPath path(int row) const
+    {
+        return m_paths.at(row);
+    }
+
+    qreal pixelSize() const { return m_pixelSize; }
+    bool doubleGlyphResolution() const { return m_doubleGlyphResolution; }
+
+signals:
+    void startGeneration(quint16 glyphCount);
+    void stopGeneration();
+    void distanceFieldGenerated();
+    void error(const QString &errorString);
+
+private slots:
+    void addDistanceField(const QImage &distanceField,
+                          const QPainterPath &path,
+                          glyph_t glyphId,
+                          quint32 ucs4);
+    void reserveSpace(quint16 glyphCount,
+                      bool doubleResolution,
+                      qreal pixelSize);
+
+private:
+    UnicodeRange unicodeRangeForUcs4(quint32 ucs4) const;
+
+    QRawFont m_font;
+    DistanceFieldModelWorker *m_worker;
+    QScopedPointer<QThread> m_workerThread;
+    quint16 m_glyphCount;
+    QVector<QImage> m_distanceFields;
+    QVector<QPainterPath> m_paths;
+    QMultiHash<UnicodeRange, glyph_t> m_glyphsPerUnicodeRange;
+    QHash<quint32, glyph_t> m_glyphsPerUcs4;
+    bool m_doubleGlyphResolution;
+    qreal m_pixelSize;
+    QMetaEnum m_rangeEnum;
+};
+
+QT_END_NAMESPACE
+
+#endif // DISTANCEFIELDMODEL_H