From 97568427349b5c7c8632912352e55dd19b579198 Mon Sep 17 00:00:00 2001
From: Nico Weber <thakis@chromium.org>
Date: Mon, 23 Jan 2023 11:00:22 -0500
Subject: [PATCH] LibGfx+icc: Add ICCProfile support for s15Fixed16ArrayType
 and print it

This is the type of the chromaticAdaptationTag, which is a required tag
in v4 profiles for all non-DeviceLink profiles.
---
 Userland/Libraries/LibGfx/ICCProfile.cpp | 24 ++++++++++++++++++++++++
 Userland/Libraries/LibGfx/ICCProfile.h   | 22 ++++++++++++++++++++++
 Userland/Utilities/icc.cpp               | 19 +++++++++++++++++++
 3 files changed, 65 insertions(+)

diff --git a/Userland/Libraries/LibGfx/ICCProfile.cpp b/Userland/Libraries/LibGfx/ICCProfile.cpp
index 2b4bfb084d..7d6bf95b58 100644
--- a/Userland/Libraries/LibGfx/ICCProfile.cpp
+++ b/Userland/Libraries/LibGfx/ICCProfile.cpp
@@ -612,6 +612,28 @@ ErrorOr<NonnullRefPtr<MultiLocalizedUnicodeTagData>> MultiLocalizedUnicodeTagDat
     return adopt_ref(*new MultiLocalizedUnicodeTagData(offset, size, move(records)));
 }
 
+ErrorOr<NonnullRefPtr<S15Fixed16ArrayTagData>> S15Fixed16ArrayTagData::from_bytes(ReadonlyBytes bytes, u32 offset, u32 size)
+{
+    // ICC v4, 10.22 s15Fixed16ArrayType
+    VERIFY(tag_type(bytes) == Type);
+    TRY(check_reserved(bytes));
+
+    // "This type represents an array of generic 4-byte (32-bit) fixed point quantity. The number of values is determined
+    //  from the size of the tag."
+    size_t byte_size = bytes.size() - 8;
+    if (byte_size % sizeof(s15Fixed16Number) != 0)
+        return Error::from_string_literal("ICC::Profile: s15Fixed16ArrayType has wrong size");
+
+    size_t count = byte_size / sizeof(s15Fixed16Number);
+    BigEndian<s15Fixed16Number> const* raw_values = bit_cast<BigEndian<s15Fixed16Number> const*>(bytes.data() + 8);
+    Vector<S15Fixed16, 9> values;
+    TRY(values.try_resize(count));
+    for (size_t i = 0; i < count; ++i)
+        values[i] = S15Fixed16::create_raw(raw_values[i]);
+
+    return adopt_ref(*new S15Fixed16ArrayTagData(offset, size, move(values)));
+}
+
 ErrorOr<NonnullRefPtr<TextDescriptionTagData>> TextDescriptionTagData::from_bytes(ReadonlyBytes bytes, u32 offset, u32 size)
 {
     // ICC v2, 6.5.17 textDescriptionType
@@ -850,6 +872,8 @@ ErrorOr<NonnullRefPtr<TagData>> Profile::read_tag(ReadonlyBytes bytes, Detail::T
     switch (type) {
     case MultiLocalizedUnicodeTagData::Type:
         return MultiLocalizedUnicodeTagData::from_bytes(tag_bytes, entry.offset_to_beginning_of_tag_data_element, entry.size_of_tag_data_element);
+    case S15Fixed16ArrayTagData::Type:
+        return S15Fixed16ArrayTagData::from_bytes(tag_bytes, entry.offset_to_beginning_of_tag_data_element, entry.size_of_tag_data_element);
     case TextDescriptionTagData::Type:
         return TextDescriptionTagData::from_bytes(tag_bytes, entry.offset_to_beginning_of_tag_data_element, entry.size_of_tag_data_element);
     case TextTagData::Type:
diff --git a/Userland/Libraries/LibGfx/ICCProfile.h b/Userland/Libraries/LibGfx/ICCProfile.h
index 3f3ae202cb..736b57035f 100644
--- a/Userland/Libraries/LibGfx/ICCProfile.h
+++ b/Userland/Libraries/LibGfx/ICCProfile.h
@@ -7,6 +7,7 @@
 #pragma once
 
 #include <AK/Error.h>
+#include <AK/FixedPoint.h>
 #include <AK/Format.h>
 #include <AK/HashMap.h>
 #include <AK/NonnullRefPtr.h>
@@ -282,6 +283,27 @@ private:
     Vector<Record> m_records;
 };
 
+// ICC v4, 10.22 s15Fixed16ArrayType
+class S15Fixed16ArrayTagData : public TagData {
+public:
+    static constexpr TagTypeSignature Type { 0x73663332 }; // 'sf32'
+
+    using S15Fixed16 = FixedPoint<16, i32>;
+
+    static ErrorOr<NonnullRefPtr<S15Fixed16ArrayTagData>> from_bytes(ReadonlyBytes, u32 offset, u32 size);
+
+    S15Fixed16ArrayTagData(u32 offset, u32 size, Vector<S15Fixed16, 9> values)
+        : TagData(offset, size, Type)
+        , m_values(move(values))
+    {
+    }
+
+    Vector<S15Fixed16, 9> const& values() const { return m_values; }
+
+private:
+    Vector<S15Fixed16, 9> m_values;
+};
+
 // ICC v2, 6.5.17 textDescriptionType
 class TextDescriptionTagData : public TagData {
 public:
diff --git a/Userland/Utilities/icc.cpp b/Userland/Utilities/icc.cpp
index 7f38fd672c..a92ec51d4e 100644
--- a/Userland/Utilities/icc.cpp
+++ b/Userland/Utilities/icc.cpp
@@ -102,6 +102,25 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
                     record.iso_3166_1_country_code >> 8, record.iso_3166_1_country_code & 0xff,
                     record.text);
             }
+        } else if (tag_data->type() == Gfx::ICC::S15Fixed16ArrayTagData::Type) {
+            // This tag can contain arbitrarily many fixed-point numbers, but in practice it's
+            // exclusively used for the 'chad' tag, where it always contains 9 values that
+            // represent a 3x3 matrix.  So print the values in groups of 3.
+            auto& fixed_array = static_cast<Gfx::ICC::S15Fixed16ArrayTagData&>(*tag_data);
+            out("    [");
+            int i = 0;
+            for (auto value : fixed_array.values()) {
+                if (i > 0) {
+                    out(",");
+                    if (i % 3 == 0) {
+                        outln();
+                        out("     ");
+                    }
+                }
+                out(" {}", value);
+                i++;
+            }
+            outln(" ]");
         } else if (tag_data->type() == Gfx::ICC::TextDescriptionTagData::Type) {
             auto& text_description = static_cast<Gfx::ICC::TextDescriptionTagData&>(*tag_data);
             outln("    ascii: \"{}\"", text_description.ascii_description());