Implement historic NXColor decoding

AppKit/CMakeLists.txt

@@ -416,6 +416,7 @@ set(AppKit_sources
 
 	NSSharingService.m
 	MacWorkspace.m
+	NSCoder+AppKit.m
 )
 
 set_source_files_properties(${AppKit_sources} LANGUAGE C)

AppKit/NSCoder+AppKit.h

@@ -0,0 +1,6 @@
+#import <Foundation/NSCoder.h>
+#import <AppKit/NSColor.h>
+
+@interface NSCoder (AppKit)
+-(NSColor*) decodeNXColor;
+@end

AppKit/NSCoder+AppKit.m

@@ -0,0 +1,126 @@
+// Copyright (C) 2020 Lubos Dolezel
+
+// Support for decoding legacy NXColors
+
+#import "NSCoder+AppKit.h"
+#import <Foundation/NSCoder.h>
+#import <Foundation/NSArchiver.h>
+
+enum {
+	kColorSingleChannel = 0x1,
+	kColorHasNamedColor = 0x4,
+	kColorTypeFlags = 0x1f,
+	kColorIsRGB = 0x40,
+	kColorOpaque = 0x80,
+};
+
+@implementation NSCoder (AppKit)
+
+-(NSColor*) decodeNXColor
+{
+	uint8_t type;
+
+	[self decodeValuesOfObjCTypes: "c", &type];
+	if ((type & kColorTypeFlags) == 2 || (type & 0x10))
+	{
+		return nil;
+	}
+
+	// RGB or CMY components
+	uint16_t component1, component2, component3;
+	if ((type & kColorTypeFlags) == kColorSingleChannel)
+	{
+		[self decodeValuesOfObjCTypes: "s", &component1];
+		component3 = component2 = component1;
+	}
+	else
+	{
+		[self decodeValuesOfObjCTypes: "sss", &component1, &component2, &component3];
+	}
+
+	uint16_t componentK = 0, componentAlpha;
+	if (!(type & kColorIsRGB))
+		[self decodeValuesOfObjCTypes: "s", &componentK];
+
+	if (!(type & kColorOpaque))
+		[self decodeValuesOfObjCTypes: "s", &componentAlpha];
+	else
+		componentAlpha = 65534; // opaque
+
+	if (type & kColorHasNamedColor)
+	{
+		NSString* colorName = nil;
+
+		const char* atom;
+		[self decodeValuesOfObjCTypes: "%", &atom];
+
+		const char* name = atom;
+		while (*name)
+		{
+			name++;
+			if (*name == '\x1B')
+				break;
+		}
+
+		if (*name)
+			colorName = [NSString stringWithCString: name encoding: NSMacOSRomanStringEncoding];
+		
+		NSString* catalogs[2] = { @"PANTONE", nil };
+		NSString* palette = nil;
+
+		if (atom)
+		{
+			int i;
+			char bufPalette[112];
+			for (i = 0; i < 100; i++)
+			{
+				if (atom[i] == '\0' || atom[i] == '\x1B')
+					break;
+				bufPalette[i] = atom[i];
+			}
+			bufPalette[i] = '\0';
+
+			if (i != 0)
+			{
+				if (i == 2 && bufPalette[0] == 0x7F)
+				{
+					// FIXME: This works differently in practice, but I don't know how
+					palette = catalogs[0];
+				}
+				else
+					palette = [NSString stringWithCString: bufPalette encoding: NSMacOSRomanStringEncoding];
+			}
+		}
+		
+		if (colorName && palette)
+		{
+			NSColor* color = [NSColor colorWithCatalogName:palette colorName:colorName];
+			if (color != nil)
+			{
+				if (componentAlpha != 0)
+				{
+					// TODO: Unless completely transparent, apply alpha
+				}
+				return color;
+			}
+		}
+	}
+
+	if (type & kColorIsRGB)
+	{
+		return [NSColor colorWithCalibratedRed: (component1 / 65534.0f)
+			green: (component2 / 65534.0f)
+			blue: (component3 / 65534.0f)
+			alpha: (componentAlpha / 65534.0f)];
+	}
+	else
+	{
+		return [NSColor colorWithDeviceCyan: (component1 / 65534.0f)
+			magenta: (component2 / 65534.0f)
+			yellow: (component3 / 65534.0f)
+			black: (componentK / 65534.0f)
+			alpha: (componentAlpha / 65534.0f)];
+	}
+}
+
+@end