LibGfx+icc: Print pcs illuminant

Author: https://github.com/nico
Commit: 79badfd650
Pull-request: https://github.com/SerenityOS/serenity/pull/16756
Reviewed-by: https://github.com/gmta

Userland/Libraries/LibGfx/ICCProfile.cpp

@@ -6,6 +6,7 @@
 
 #include <AK/Endian.h>
 #include <LibGfx/ICCProfile.h>
+#include <math.h>
 #include <time.h>
 
 // V2 spec: https://color.org/specification/ICC.1-2001-04.pdf
@@ -26,6 +27,21 @@ struct DateTimeNumber {
     BigEndian<u16> seconds;
 };
 
+// ICC V4, 4.6 s15Fixed16Number
+using s15Fixed16Number = i32;
+
+// ICC V4, 4.14 XYZNumber
+struct XYZNumber {
+    BigEndian<s15Fixed16Number> x;
+    BigEndian<s15Fixed16Number> y;
+    BigEndian<s15Fixed16Number> z;
+
+    operator XYZ() const
+    {
+        return XYZ { x / (double)0x1'0000, y / (double)0x1'0000, z / (double)0x1'0000 };
+    }
+};
+
 ErrorOr<time_t> parse_date_time_number(DateTimeNumber const& date_time)
 {
     // ICC V4, 4.2 dateTimeNumber
@@ -91,9 +107,7 @@ struct ICCHeader {
     BigEndian<u64> device_attributes;
     BigEndian<u32> rendering_intent;
 
-    BigEndian<i32> pcs_illuminant_x;
-    BigEndian<i32> pcs_illuminant_y;
-    BigEndian<i32> pcs_illuminant_z;
+    XYZNumber pcs_illuminant;
 
     BigEndian<u32> profile_creator;
 
@@ -194,6 +208,18 @@ ErrorOr<RenderingIntent> parse_rendering_intent(ICCHeader const& header)
     return Error::from_string_literal("ICC::Profile: Invalid rendering intent");
 }
 
+ErrorOr<XYZ> parse_pcs_illuminant(ICCHeader const& header)
+{
+    // ICC v4, 7.2.16 PCS illuminant field
+    XYZ xyz = (XYZ)header.pcs_illuminant;
+
+    /// "The value, when rounded to four decimals, shall be X = 0,9642, Y = 1,0 and Z = 0,8249."
+    if (round(xyz.x * 10'000) != 9'642 || round(xyz.y * 10'000) != 10'000 || round(xyz.z * 10'000) != 8'249)
+        return Error::from_string_literal("ICC::Profile: Invalid pcs illuminant");
+
+    return xyz;
+}
+
 ErrorOr<time_t> parse_creation_date_time(ICCHeader const& header)
 {
     // iCC v4, 7.2.8 Date and time field
@@ -337,6 +363,7 @@ ErrorOr<NonnullRefPtr<Profile>> Profile::try_load_from_externally_owned_memory(R
     profile->m_creation_timestamp = TRY(parse_creation_date_time(header));
     profile->m_flags = Flags { header.profile_flags };
     profile->m_rendering_intent = TRY(parse_rendering_intent(header));
+    profile->m_pcs_illuminant = TRY(parse_pcs_illuminant(header));
 
     return profile;
 }

Userland/Libraries/LibGfx/ICCProfile.h

@@ -115,6 +115,12 @@ private:
     u32 m_bits = 0;
 };
 
+struct XYZ {
+    double x { 0 };
+    double y { 0 };
+    double z { 0 };
+};
+
 class Profile : public RefCounted<Profile> {
 public:
     static ErrorOr<NonnullRefPtr<Profile>> try_load_from_externally_owned_memory(ReadonlyBytes bytes);
@@ -129,6 +135,7 @@ public:
     time_t creation_timestamp() const { return m_creation_timestamp; }
     Flags flags() const { return m_flags; }
     RenderingIntent rendering_intent() const { return m_rendering_intent; }
+    const XYZ& pcs_illuminant() const { return m_pcs_illuminant; }
 
 private:
     Version m_version;
@@ -138,6 +145,7 @@ private:
     time_t m_creation_timestamp;
     Flags m_flags;
     RenderingIntent m_rendering_intent;
+    XYZ m_pcs_illuminant;
 };
 
 }
@@ -150,4 +158,12 @@ struct Formatter<Gfx::ICC::Version> : Formatter<FormatString> {
         return Formatter<FormatString>::format(builder, "{}.{}.{}"sv, version.major_version(), version.minor_version(), version.bugfix_version());
     }
 };
+
+template<>
+struct Formatter<Gfx::ICC::XYZ> : Formatter<FormatString> {
+    ErrorOr<void> format(FormatBuilder& builder, Gfx::ICC::XYZ const& xyz)
+    {
+        return Formatter<FormatString>::format(builder, "X = {}, Y = {}, Z = {}"sv, xyz.x, xyz.y, xyz.z);
+    }
+};
 }

Userland/Utilities/icc.cpp

@@ -37,6 +37,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
         outln("  CMM bits: 0x{:04x}", color_management_module_bits);
 
     outln("rendering intent: {}", Gfx::ICC::rendering_intent_name(profile->rendering_intent()));
+    outln("pcs illuminant: {}", profile->pcs_illuminant());
 
     return 0;
 }