new Gfx::Length contains both absolute and relative length.

Author: simzer

src/base/gfx/length.cpp

@@ -0,0 +1,28 @@
+#include "length.h"
+
+#include <stdexcept>
+
+using namespace Gfx;
+
+Length::Length(const std::string &s)
+{
+	Text::ValueUnit parser(s);
+	auto unit = parser.getUnit();
+	if (unit == "%")
+	{
+		relative = parser.getValue();
+	}
+	else if (unit == "px" || unit.empty())
+	{
+		absolute = parser.getValue();
+	}
+	else throw std::logic_error("invalid length unit: " + unit);
+}
+
+Length::operator std::string() const
+{
+	if (relative == 0.0) return std::to_string(absolute) + "px";
+	if (absolute == 0.0) return std::to_string(relative) + "%";
+	return std::to_string(absolute) + "px"
+		+ "+" + std::to_string(relative) + "%";
+}

src/base/gfx/length.h

@@ -0,0 +1,50 @@
+#ifndef GFX_LENGTH
+#define GFX_LENGTH
+
+#include <string>
+
+#include "base/text/valueunit.h"
+
+namespace Gfx
+{
+
+class Length
+{
+public:
+	double absolute;
+	double relative;
+
+	Length() : absolute(0), relative(0) {}
+
+	static Length Absolute(double value) { return Length(value, 0); }
+	static Length Relative(double value) { return Length(0, value); }
+
+	Length(double abs, double rel) : 
+		absolute(abs), relative(rel)
+	{}
+
+	explicit Length(const std::string &s);
+
+	double get(double reference) const {
+		return absolute + relative * reference;
+	}
+
+	explicit operator std::string() const;
+
+	bool operator==(const Length &other) const {
+		return absolute == other.absolute
+			&& relative == other.relative;
+	}
+
+	Length operator*(double scale) const {
+		return Length(absolute * scale, relative * scale);
+	}
+
+	Length operator+(const Length &other) const {
+		return Length(absolute + other.absolute, relative + other.relative);
+	}
+};
+
+}
+
+#endif