Recognise some symbolic colors (red, green, blue, yellow, black, white, gr[ae]y, and more)

Color.cpp

@@ -2,16 +2,60 @@
 #include <cctype>
 #include <stdexcept>
 #include <cstdlib>
+#include <map>
+#include <string>
+#include <cctype>
 #include "Color.h"
 
+class ColorTable : public std::map<std::string, Color>
+{
+public:
+	ColorTable(void)
+	{
+	map<std::string, Color> &table = *this;
+	table["white"] =	Color(0xff, 0xff, 0xff);
+	table["black"] =	Color(0, 0, 0);
+	table["gray"] =		Color(0x7f, 0x7f, 0x7f);
+	table["grey"] =		Color(0x7f, 0x7f, 0x7f);
+
+	table["red"] =		Color(0xff, 0, 0);
+	table["green"] =	Color(0, 0xff, 0);
+	table["blue"] =		Color(0, 0, 0xff);
+
+	table["yellow"] =	Color(0xff, 0xff, 0);
+	table["magenta"] =	Color(0xff, 0, 0xff);
+	table["fuchsia"] =	Color(0xff, 0, 0xff);
+	table["cyan"] =		Color(0, 0xff, 0xff);
+	table["aqua"] =		Color(0, 0xff, 0xff);
+
+	table["orange"] =	Color(0xff, 0x7f, 0);
+	table["chartreuse"] =	Color(0x7f, 0xff, 0);
+	table["pink"] =		Color(0xff, 0, 0x7f);
+	table["violet"] =	Color(0x7f, 0, 0xff);
+	table["springgreen"] =	Color(0, 0xff, 0x7f);
+	table["azure"] =	Color(0, 0x7f, 0xff);
+
+	table["brown"] =	Color(0x7f, 0x3f, 0);
+	}
+};
+ColorTable colorTable;
+
+
 // alpha:
 //	 0: don't expect/allow alpha
 //	 1: allow alpha; defaults to 255 (0xff)
 //	-1: allow alpha but ignore - set to to 255 (0xff)
-Color::Color(const std::string &color, int alpha)
+Color::Color(std::string color, int alpha)
 {
 	if (color[0] != '#') {
-		throw std::runtime_error("Color does not begin with #");
+		int l = color.length();
+		for (int i = 0; i < l; i++)
+			color[i] = tolower(color[i]);
+		if (colorTable.count(color) > 0) {
+			*this = colorTable[color];
+			return;
+		}
+		throw std::runtime_error(std::string("Symbolic color '") + color + "' not known, or color does not begin with #");
 	}
 	if (std::string::npos != color.find_first_not_of("0123456789abcdefABCDEF",1)) {
 		throw std::runtime_error("Color value has invalid digits (expected: [0-9a-zA-Z])");

Color.h

@@ -9,7 +9,7 @@ struct Color {
 	Color(uint32_t c): r((c >> 16) & 0xff), g((c >> 8) & 0xff), b((c >> 0) & 0xff ), a((c >> 24) & 0xff) {};
 	Color(uint8_t r, uint8_t g, uint8_t b): r(r), g(g), b(b), a(0xff) {};
 	Color(uint8_t r, uint8_t g, uint8_t b, uint8_t a): r(r), g(g), b(b), a(a) {};
-	Color(const std::string &s, int alpha = 1);
+	Color(std::string s, int alpha = 1);
 	Color &operator=(const Color &c);
 	unsigned to_uint() const { return (unsigned(a) << 24) + (unsigned(r) << 16) + (unsigned(g) << 8) + unsigned(b); }
 	//libgd treats 127 as transparent, and 0 as opaque ...

mapper.cpp

@@ -108,6 +108,11 @@ void usage()
 			"Color formats:\n"
 			"\t'#000' or '#000000'                                  (RGB)\n"
 			"\t'#0000' or '#0000000'                                (ARGB - usable if an alpha value is allowed)\n"
+			"\tSome symbolic color names:\n"
+			"\t\twhite, black, gray, grey, red, green, blue,\n"
+			"\t\tyellow, magenta, fuchsia, cyan, aqua,\n"
+			"\t\torange, chartreuse, pink, violet, springgreen, azure\n"
+			"\t\tbrown (= 50% orange)\n"
 			"Geometry formats:\n"
 			"\t<width>x<heigth>[+|-<xoffset>+|-<yoffset>]           (dimensions and corner)\n"
 			"\t<xoffset>,<yoffset>+<width>+<height>                 (corner and dimensions)\n"