Add new colourmaps feature for visualisations.

cvd/colourmaps.h

@@ -0,0 +1,115 @@
+#ifndef CVD_INC_COLOURMAPS_H
+#define CVD_INC_COLOURMAPS_H
+
+#include <cvd/rgb.h>
+#include <cvd/rgba.h>
+#include <cvd/internal/convert_pixel_types.h>
+#include <cvd/internal/rgb_components.h>
+
+#include <utility>
+
+namespace CVD
+{
+
+	namespace Internal
+	{
+
+		Rgb<float> hot(float d)
+		{
+			using std::max; 
+			using std::min;
+			d = max(0.f, min(d, 1.0f));
+
+			if(d < 1./3.)
+				return Rgb<float>(d*3, 0, 0);
+			else if(d < 2./3.)
+				return Rgb<float>(1, (d-1./3.)*3, 0);
+			else
+				return Rgb<float>(1, 1, (d-2./3.)*3);
+		}
+
+		Rgb<float> jet(float d)
+		{
+			using std::max; 
+			using std::min;
+			d = max(0.f, min(d, 1.0f));
+			double r=0,g=0,b=0;
+
+			if(d < 1./4.) // Red to yello
+			{
+				r=1;
+				g=d/(1./4.);
+				b=0;
+			}
+			else if(d < 2./4.) //Yello to green
+			{
+				g=1;
+				r=1-(d-1./4.)/(1./4.);
+				b=0;
+			}	
+			else if(d < 3./4.) // Green to cyan
+			{
+				r=0;
+				g=1;
+				b=(d-2./4.)/(1./4.);
+			}
+			else //cyan to blue
+			{
+				b=1;
+				g = 1- (d-3./4.)/(1./4.);
+				r=0;
+			}
+
+			return Rgb<float>(r, g, b);
+		}
+
+		Rgb<float> gkr(float d)
+		{
+			using std::max; 
+			using std::min;
+
+			if(d < 1./2.)
+				return Rgb<float>(1-d*2, 0, 0);
+			else
+				return Rgb<float>(0, (d-1./2.)*2, 0);
+
+
+		}
+
+
+		template<class C, class D>
+		Rgb<C> conv(const D& func, float d)
+		{
+			Rgb<float> col = func(d);
+			Rgb<C> r;
+			Pixel::ConvertPixels<Rgb<float>, Rgb<C> >::convert(&col, &r, 1);
+			return r;
+		}
+	};
+
+
+
+	template<class C> struct Colourmap;
+
+
+	///Handy class for generating a colourscale.
+	///
+	///Expected range is \f$[0, 1)\f$, and clamping is performed.
+	///Currently only RGB scales are provided. TODO: RGBA scales.
+	///@ingroup gDraw
+	template<class C> struct Colourmap<Rgb<C> >
+	{
+
+		///Glow/Hot colourscale (red-yellow-white)
+		static Rgb<C> hot(double d) { return Internal::conv<C>(Internal::hot, d);} 
+
+		///Jet colourscale (red-yellow-green-cyan-blue)
+		static Rgb<C> jet(double d) { return Internal::conv<C>(Internal::jet, d);} 
+
+		///Green-black-red colourscale
+		static Rgb<C> gkr(double d) { return Internal::conv<C>(Internal::gkr, d);} 
+	};
+};
+
+
+#endif