LibGfx/TIFF: Extract metadata-related definition to their own file

Author: https://github.com/LucasChollet
Commit: https://github.com/SerenityOS/serenity/commit/34d91dec5b
Pull-request: https://github.com/SerenityOS/serenity/pull/21918
Reviewed-by: https://github.com/nico ✅

Userland/Libraries/LibGfx/ImageFormats/TIFFLoader.cpp

@@ -9,6 +9,7 @@
 #include <AK/Endian.h>
 #include <AK/String.h>
 #include <LibCompress/LZWDecoder.h>
+#include <LibGfx/ImageFormats/TIFFMetadata.h>
 
 namespace Gfx {
 
@@ -23,13 +24,6 @@ public:
         FrameDecoded,
     };
 
-    template<OneOf<u32, i32> x32>
-    struct Rational {
-        using Type = x32;
-        x32 numerator;
-        x32 denominator;
-    };
-
     TIFFLoadingContext(NonnullOwnPtr<FixedMemoryStream> stream)
         : m_stream(move(stream))
     {
@@ -77,49 +71,6 @@ private:
         BigEndian,
     };
 
-    enum class Type {
-        Byte = 1,
-        ASCII = 2,
-        UnsignedShort = 3,
-        UnsignedLong = 4,
-        UnsignedRational = 5,
-        Undefined = 7,
-        SignedLong = 9,
-        SignedRational = 10,
-        Float = 11,
-        Double = 12,
-        UTF8 = 129,
-    };
-
-    using Value = Variant<u8, String, u16, u32, Rational<u32>, i32, Rational<i32>>;
-
-    // This enum is progessively defined across sections but summarized in:
-    // Appendix A: TIFF Tags Sorted by Number
-    enum class Compression {
-        NoCompression = 1,
-        CCITT = 2,
-        Group3Fax = 3,
-        Group4Fax = 4,
-        LZW = 5,
-        JPEG = 6,
-        PackBits = 32773,
-    };
-
-    enum class Predictor {
-        None = 1,
-        HorizontalDifferencing = 2,
-    };
-
-    struct Metadata {
-        IntSize size {};
-        Array<u16, 3> bits_per_sample {};
-        Compression compression {};
-        Predictor predictor {};
-        Vector<u32> strip_offsets {};
-        u32 rows_per_strip {};
-        Vector<u32> strip_bytes_count {};
-    };
-
     template<typename ByteReader>
     ErrorOr<void> loop_over_pixels(ByteReader&& byte_reader, Function<ErrorOr<void>(u32)> initializer = {})
     {
@@ -677,8 +628,8 @@ ErrorOr<ImageFrameDescriptor> TIFFImageDecoderPlugin::frame(size_t index, Option
 }
 
 template<typename T>
-struct AK::Formatter<Gfx::TIFF::TIFFLoadingContext::Rational<T>> : Formatter<FormatString> {
-    ErrorOr<void> format(FormatBuilder& builder, Gfx::TIFF::TIFFLoadingContext::Rational<T> value)
+struct AK::Formatter<Gfx::TIFF::Rational<T>> : Formatter<FormatString> {
+    ErrorOr<void> format(FormatBuilder& builder, Gfx::TIFF::Rational<T> value)
     {
         return Formatter<FormatString>::format(builder, "{} ({}/{})"sv, static_cast<double>(value.numerator) / value.denominator, value.numerator, value.denominator);
     }

Userland/Libraries/LibGfx/ImageFormats/TIFFMetadata.h

@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2023, Lucas Chollet <lucas.chollet@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Variant.h>
+#include <AK/Vector.h>
+#include <LibGfx/Size.h>
+
+namespace Gfx {
+
+namespace TIFF {
+
+enum class Type {
+    Byte = 1,
+    ASCII = 2,
+    UnsignedShort = 3,
+    UnsignedLong = 4,
+    UnsignedRational = 5,
+    Undefined = 7,
+    SignedLong = 9,
+    SignedRational = 10,
+    Float = 11,
+    Double = 12,
+    UTF8 = 129,
+};
+
+template<OneOf<u32, i32> x32>
+struct Rational {
+    using Type = x32;
+    x32 numerator;
+    x32 denominator;
+};
+
+using Value = Variant<u8, String, u16, u32, Rational<u32>, i32, Rational<i32>>;
+
+// This enum is progessively defined across sections but summarized in:
+// Appendix A: TIFF Tags Sorted by Number
+enum class Compression {
+    NoCompression = 1,
+    CCITT = 2,
+    Group3Fax = 3,
+    Group4Fax = 4,
+    LZW = 5,
+    JPEG = 6,
+    PackBits = 32773,
+};
+
+enum class Predictor {
+    None = 1,
+    HorizontalDifferencing = 2,
+};
+
+}
+
+struct Metadata {
+    IntSize size {};
+    Array<u16, 3> bits_per_sample {};
+    TIFF::Compression compression {};
+    TIFF::Predictor predictor {};
+    Vector<u32> strip_offsets {};
+    u32 rows_per_strip {};
+    Vector<u32> strip_bytes_count {};
+};
+
+}