1 files changed, 149 insertions, 0 deletions
diff --git a/Userland/Libraries/LibTTF/Tables.h b/Userland/Libraries/LibTTF/Tables.h
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+++ b/Userland/Libraries/LibTTF/Tables.h
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+/*
+ * Copyright (c) 2020, Srimanta Barua <srimanta.barua1@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/Span.h>
+
+namespace TTF {
+
+enum class IndexToLocFormat {
+    Offset16,
+    Offset32,
+};
+
+class Head {
+public:
+    static Optional<Head> from_slice(const ReadonlyBytes&);
+    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,
+    };
+
+    Head(const ReadonlyBytes& slice)
+        : m_slice(slice)
+    {
+    }
+
+    ReadonlyBytes m_slice;
+};
+
+class Hhea {
+public:
+    static Optional<Hhea> from_slice(const ReadonlyBytes&);
+    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,
+    };
+
+    Hhea(const ReadonlyBytes& slice)
+        : m_slice(slice)
+    {
+    }
+
+    ReadonlyBytes m_slice;
+};
+
+class Maxp {
+public:
+    static Optional<Maxp> from_slice(const ReadonlyBytes&);
+    u16 num_glyphs() const;
+
+private:
+    enum class Offsets {
+        NumGlyphs = 4
+    };
+    enum class Sizes {
+        TableV0p5 = 6,
+    };
+
+    Maxp(const ReadonlyBytes& slice)
+        : m_slice(slice)
+    {
+    }
+
+    ReadonlyBytes m_slice;
+};
+
+struct GlyphHorizontalMetrics {
+    u16 advance_width;
+    i16 left_side_bearing;
+};
+
+class Hmtx {
+public:
+    static Optional<Hmtx> from_slice(const ReadonlyBytes&, u32 num_glyphs, u32 number_of_h_metrics);
+    GlyphHorizontalMetrics get_glyph_horizontal_metrics(u32 glyph_id) const;
+
+private:
+    enum class Sizes {
+        LongHorMetric = 4,
+        LeftSideBearing = 2
+    };
+
+    Hmtx(const ReadonlyBytes& 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)
+    {
+    }
+
+    ReadonlyBytes m_slice;
+    u32 m_num_glyphs { 0 };
+    u32 m_number_of_h_metrics { 0 };
+};
+
+}