Fixed HSL algorithm. It prefers colours to white/black

This reverts commit 0e7aba5991.

colour_extractor.cpp

@@ -5,36 +5,36 @@
 
 // CONSTRUCTORS
 ColourExtractor::ColourExtractor(size_t h_levels, size_t s_levels,
-	size_t v_levels)
+	size_t l_levels)
 :m_pixels(NULL), m_max_colour_count(0), m_h_levels(h_levels),
-	m_s_levels(s_levels), m_v_levels(v_levels)
+	m_s_levels(s_levels), m_l_levels(l_levels)
 {
-	m_pixels = new size_t[m_h_levels * m_s_levels * m_v_levels];
+	m_pixels = new size_t[m_h_levels * m_s_levels * m_l_levels];
-	memset(m_pixels, 0, m_h_levels * m_s_levels * m_v_levels * sizeof(size_t));
+	memset(m_pixels, 0, m_h_levels * m_s_levels * m_l_levels * sizeof(size_t));
 }
 
 // PROTECTED FUNCS
-size_t ColourExtractor::quantize(struct ColourHSV hsv) const
+size_t ColourExtractor::quantize(struct ColourHSL hsl) const
 {
 	size_t result = 0;
 
 	size_t h_quant = 0;
 	size_t s_quant = 0;
-	size_t v_quant = 0;
+	size_t l_quant = 0;
 
-	v_quant = static_cast<size_t>(round(hsv.v * (m_v_levels - 1)));
+	l_quant = static_cast<size_t>(round(hsl.l * (m_l_levels - 1)));
-	if (0 == v_quant)
+	if (0 == l_quant)
 	{
 		goto end;
 	}
 
-	s_quant = static_cast<size_t>(round(hsv.s * (m_s_levels - 1)));
+	s_quant = static_cast<size_t>(round(hsl.s * (m_s_levels - 1)));
 	if (0 == s_quant)
 	{
 		goto end;
 	}
 
-	h_quant = static_cast<size_t>(round(hsv.h / 360.0 * (m_h_levels - 1)));
+	h_quant = static_cast<size_t>(round(hsl.h / 360.0 * (m_h_levels - 1)));
 
 	end:
 	result += h_quant;
@@ -42,21 +42,21 @@ size_t ColourExtractor::quantize(struct ColourHSV hsv) const
 	result *= m_s_levels;
 	result += s_quant;
 
-	result *= m_v_levels;
+	result *= m_l_levels;
-	result += v_quant;
+	result += l_quant;
 
 	return result;
 }
 
-struct ColourHSV ColourExtractor::dequantize(size_t colour) const
+struct ColourHSL ColourExtractor::dequantize(size_t colour) const
 {
-	struct ColourHSV result;
+	struct ColourHSL result;
 	size_t h_quant;
 	size_t s_quant;
-	size_t v_quant;
+	size_t l_quant;
 
-	v_quant = colour % m_v_levels;
+	l_quant = colour % m_l_levels;
-	colour /= m_v_levels;
+	colour /= m_l_levels;
 
 	s_quant = colour % m_s_levels;
 	colour /= m_s_levels;
@@ -65,31 +65,31 @@ struct ColourHSV ColourExtractor::dequantize(size_t colour) const
 
 	result.h = static_cast<double>(h_quant) * 360.0 / (m_h_levels - 1);
 	result.s = static_cast<double>(s_quant) / (m_s_levels - 1);
-	result.v = static_cast<double>(v_quant) / (m_v_levels - 1);
+	result.l = static_cast<double>(l_quant) / (m_l_levels - 1);
 
 	return result;
 }
 
 // PUBLIC FUNCS
 void ColourExtractor::get_quantization_levels(size_t& h_levels,
-	size_t& s_levels, size_t& v_levels) const
+	size_t& s_levels, size_t& l_levels) const
 {
 	h_levels = m_h_levels;
 	s_levels = m_s_levels;
-	v_levels = m_v_levels;
+	l_levels = m_l_levels;
 }
 
 void ColourExtractor::set_quantization_levels(size_t h_levels, size_t s_levels,
-		size_t v_levels)
+		size_t l_levels)
 {
 	delete[] m_pixels;
 
 	m_h_levels = h_levels;
 	m_s_levels = s_levels;
-	m_v_levels = v_levels;
+	m_l_levels = l_levels;
 
-	m_pixels = new size_t[m_h_levels * m_s_levels * m_v_levels];
+	m_pixels = new size_t[m_h_levels * m_s_levels * m_l_levels];
-	memset(m_pixels, 0, m_h_levels * m_s_levels * m_v_levels * sizeof(size_t));
+	memset(m_pixels, 0, m_h_levels * m_s_levels * m_l_levels * sizeof(size_t));
 }
 
 size_t ColourExtractor::get_h_quantization_levels() const
@@ -103,8 +103,8 @@ void ColourExtractor::set_h_quantization_levels(size_t h_levels)
 
 	m_h_levels = h_levels;
 
-	m_pixels = new size_t[m_h_levels * m_s_levels * m_v_levels];
+	m_pixels = new size_t[m_h_levels * m_s_levels * m_l_levels];
-	memset(m_pixels, 0, m_h_levels * m_s_levels * m_v_levels * sizeof(size_t));
+	memset(m_pixels, 0, m_h_levels * m_s_levels * m_l_levels * sizeof(size_t));
 }
 
 size_t ColourExtractor::get_s_quantization_levels() const
@@ -118,30 +118,30 @@ void ColourExtractor::set_s_quantization_levels(size_t s_levels)
 
 	m_s_levels = s_levels;
 
-	m_pixels = new size_t[m_h_levels * m_s_levels * m_v_levels];
+	m_pixels = new size_t[m_h_levels * m_s_levels * m_l_levels];
-	memset(m_pixels, 0, m_h_levels * m_s_levels * m_v_levels * sizeof(size_t));
+	memset(m_pixels, 0, m_h_levels * m_s_levels * m_l_levels * sizeof(size_t));
 }
 
 size_t ColourExtractor::get_v_quantization_levels() const
 {
-	return m_v_levels;
+	return m_l_levels;
 }
 
-void ColourExtractor::set_v_quantization_levels(size_t v_levels)
+void ColourExtractor::set_v_quantization_levels(size_t l_levels)
 {
 	delete[] m_pixels;
 
-	m_v_levels = v_levels;
+	m_l_levels = l_levels;
 
-	m_pixels = new size_t[m_h_levels * m_s_levels * m_v_levels];
+	m_pixels = new size_t[m_h_levels * m_s_levels * m_l_levels];
-	memset(m_pixels, 0, m_h_levels * m_s_levels * m_v_levels * sizeof(size_t));
+	memset(m_pixels, 0, m_h_levels * m_s_levels * m_l_levels * sizeof(size_t));
 }
 
-void ColourExtractor::add_pixel(struct ColourHSV hsv)
+void ColourExtractor::add_pixel(struct ColourHSL hsl)
 {
 	size_t colour_quant;
 
-	colour_quant = quantize(hsv);
+	colour_quant = quantize(hsl);
 	m_pixels[colour_quant] += 1;
 
 	if (m_max_colour_count < m_pixels[colour_quant])
@@ -152,22 +152,22 @@ void ColourExtractor::add_pixel(struct ColourHSV hsv)
 
 void ColourExtractor::clear_pixels()
 {
-	for (size_t i = 0; i < m_h_levels * m_s_levels * m_v_levels; ++i)
+	for (size_t i = 0; i < m_h_levels * m_s_levels * m_l_levels; ++i)
 	{
 		m_pixels[i] = 0;
 	}
 	m_max_colour_count = 0;
 }
 
-struct ColourHSV ColourExtractor::extract_colour() const
+struct ColourHSL ColourExtractor::extract_colour() const
 {
-	struct ColourHSV result = {0.0, 0.0, 0.0};
+	struct ColourHSL result = {0.0, 0.0, 0.0};
-	struct ColourHSV temp_colour;
+	struct ColourHSL temp_colour;
 	size_t max_colour_value = 0;
 	size_t temp_colour_value;
 	double temp_colour_weight;
 
-	for (size_t i = 0; i < m_h_levels * m_s_levels * m_v_levels; ++i)
+	for (size_t i = 0; i < m_h_levels * m_s_levels * m_l_levels; ++i)
 	{
 		if (0 == m_pixels[i])
 		{

colour_extractor.h

@@ -7,7 +7,7 @@
 
 class ColourExtractor
 {
-private:
+protected:
 	// Holds all quantized pixels
 	size_t* m_pixels;
 
@@ -17,30 +17,30 @@ private:
 	// Quantization levels for the HSV colours
 	size_t m_h_levels;
 	size_t m_s_levels;
-	size_t m_v_levels;
+	size_t m_l_levels;
 
 	// Quantizes the colour
-	size_t quantize(struct ColourHSV hsv) const;
+	size_t quantize(struct ColourHSL hsl) const;
 
 	// Dequantizes the colour
-	struct ColourHSV dequantize(size_t colour) const;
+	struct ColourHSL dequantize(size_t colour) const;
 
 protected:
 	// Evaluates the given colour based on its weight
-	virtual size_t evaluate_colour(struct ColourHSV hsv, double weight)
+	virtual size_t evaluate_colour(struct ColourHSL hsl, double weight)
 		const = 0;
 
 public:
 	// Params: HSV quantization levels
 	ColourExtractor(size_t h_levels = 36, size_t s_levels = 10,
-		size_t v_levels = 10);
+		size_t l_levels = 10);
 
 	void get_quantization_levels(size_t& h_levels, size_t& s_levels,
-		size_t& v_levels) const;
+		size_t& l_levels) const;
 	
 	// Note: clears all pixels
 	void set_quantization_levels(size_t h_levels, size_t s_levels,
-		size_t v_levels);
+		size_t l_levels);
 
 	size_t get_h_quantization_levels() const;
 
@@ -55,16 +55,16 @@ public:
 	size_t get_v_quantization_levels() const;
 	
 	// Note: clears all pixels
-	void set_v_quantization_levels(size_t v_levels);
+	void set_v_quantization_levels(size_t l_levels);
 
 	// Adds a pixel to be considered for extraction
-	void add_pixel(struct ColourHSV hsv);
+	void add_pixel(struct ColourHSL hsl);
 
 	// Clears all pixels
 	void clear_pixels();
 
 	// Extracts a single colour from all added pixels
-	struct ColourHSV extract_colour() const;
+	struct ColourHSL extract_colour() const;
 
 	~ColourExtractor();
 };

complimentary_colour_extractor.cpp

@@ -1,32 +1,31 @@
 #include "complimentary_colour_extractor.h"
-
 #include <math.h>
 
 // CONSTRUCTORS
-ComplimentaryColourExtractor::ComplimentaryColourExtractor(struct ColourHSV hsv,
+ComplimentaryColourExtractor::ComplimentaryColourExtractor(struct ColourHSL hsl,
 	size_t h_levels, size_t s_levels, size_t v_levels)
-:ColourExtractor(h_levels, s_levels, v_levels), m_main_colour(hsv)
+:ColourExtractor(h_levels, s_levels, v_levels), m_main_colour(hsl)
 {
 }
 
 // PROTECTED FUNCS
-size_t ComplimentaryColourExtractor::evaluate_colour(struct ColourHSV hsv,
+size_t ComplimentaryColourExtractor::evaluate_colour(struct ColourHSL hsl,
 	double weight) const
 {
 	size_t result = 0;
 	double angle_delta;
-	double additional_colour_weight;
 
-	if ((0.0 == hsv.s) || (0.0 == m_main_colour.s))
+	if ((0 == (1.0 - fabs(2 * m_main_colour.l - 1.0))) ||
+		(0 == (1.0 - fabs(2 * hsl.l - 1.0))) ||
+		(0 == m_main_colour.s) ||
+		(0 == hsl.s))
 	{
-		angle_delta = 180.0;
+		angle_delta = 90.0;
-		additional_colour_weight = 0.5;
 	}
 	else
 	{
-		additional_colour_weight = 1.0;
 		/* SECTION BEGIN */
-		angle_delta = fabs(hsv.h - m_main_colour.h);
+		angle_delta = fabs(hsl.h - m_main_colour.h);
 		if (angle_delta > 180.0F)
 		{
 			angle_delta = 360.0F - angle_delta;
@@ -34,22 +33,20 @@ size_t ComplimentaryColourExtractor::evaluate_colour(struct ColourHSV hsv,
 		/* SECTION END */
 	}
 
-	// result = static_cast<size_t>(round(1000.0 * pow(weight, 0.3) * hsv.v *
+	result = static_cast<size_t>(round(1000.0 * pow(weight, 0.3) * angle_delta *
-	//     fmin(1.0, hsv.v + hsv.s) * additional_colour_weight * angle_delta));
+		(hsl.s + 1.0 / m_s_levels) *
-
+		pow(((1.0 - fabs(2 * hsl.l - 1.0)) * (1 - 1.0 / m_l_levels) + 1.0 / m_l_levels), 0.3)));
-	result = static_cast<size_t>(round(1000.0 * pow(weight, 0.3) * hsv.v *
-		additional_colour_weight * angle_delta));
 
 	return result;
 }
 
 // PUBLIC FUNCS
-struct ColourHSV ComplimentaryColourExtractor::get_main_colour() const
+struct ColourHSL ComplimentaryColourExtractor::get_main_colour() const
 {
 	return m_main_colour;
 }
 
-void ComplimentaryColourExtractor::set_main_colour(struct ColourHSV hsv)
+void ComplimentaryColourExtractor::set_main_colour(struct ColourHSL hsl)
 {
-	m_main_colour = hsv;
+	m_main_colour = hsl;
 }

complimentary_colour_extractor.h

@@ -7,18 +7,18 @@ class ComplimentaryColourExtractor : public ColourExtractor
 {
 private:
 	// Main colour against which we are finding the complimentary
-	struct ColourHSV m_main_colour;
+	struct ColourHSL m_main_colour;
 
 protected:
 	// Implemented - Evaluates the given colour based on its weight
-	virtual size_t evaluate_colour(struct ColourHSV hsv, double weight) const;
+	virtual size_t evaluate_colour(struct ColourHSL hsl, double weight) const;
 
 public:
-	ComplimentaryColourExtractor(struct ColourHSV hsv, size_t h_levels = 36,
+	ComplimentaryColourExtractor(struct ColourHSL hsl, size_t h_levels = 36,
 		size_t s_levels = 10, size_t v_levels = 10);
 
-	struct ColourHSV get_main_colour() const;
+	struct ColourHSL get_main_colour() const;
-	void set_main_colour(struct ColourHSV hsv);
+	void set_main_colour(struct ColourHSL hsl);
 };
 
 #endif // COMPLIMENTARY_COLOUR_EXTRACTOR_H_

main.cpp

@@ -12,13 +12,6 @@
 
 using namespace std;
 
-void usage(char *name)
-{
-	cout << "Usage: " << name << " [input image]" << endl;
-	cout << "Supported image formats: JPG, PNG, TGA, BMP, GIF" << endl;
-	cout << "Image must have 3 or more channels" << endl;
-}
-
 void print_pixel(ColourRGB rgb)
 {
 	uint8_t r = static_cast<uint8_t>(round(rgb.r * 255));
@@ -28,6 +21,13 @@ void print_pixel(ColourRGB rgb)
 	printf("#%02x%02x%02x - %3d %3d %3d", r, g ,b, r, g, b);
 }
 
+void usage(char *name)
+{
+	cout << "Usage: " << name << " [input image]" << endl;
+	cout << "Supported image formats: JPG, PNG, TGA, BMP, GIF" << endl;
+	cout << "Image must have 3 or more channels" << endl;
+}
+
 int main(int argc, char **argv)
 {
 	int x_size;
@@ -37,8 +37,8 @@ int main(int argc, char **argv)
 	unsigned char *image = nullptr;
 	ColourRGB pixel;
 	ColourRGB pixel2;
-	ColourHSV pixel_hsv;
+	ColourHSL pixel_hsl;
-	MainColourExtractor main_extractor(0.2, 36, 10, 10);
+	MainColourExtractor main_extractor(36, 10, 10);
 	ComplimentaryColourExtractor comp_extractor({0, 0, 0}, 36, 10, 10);
 
 	if (argc < 2)
@@ -85,16 +85,16 @@ int main(int argc, char **argv)
 			// TODO: Handle alpha here
 		}
 
-		pixel_hsv = RGBtoHSV(pixel);
+		pixel_hsl = RGBtoHSL(pixel);
-		main_extractor.add_pixel(pixel_hsv);
+		main_extractor.add_pixel(pixel_hsl);
-		comp_extractor.add_pixel(pixel_hsv);
+		comp_extractor.add_pixel(pixel_hsl);
 	}
 	stbi_image_free(image);
 
-	pixel_hsv = main_extractor.extract_colour();
+	pixel_hsl = main_extractor.extract_colour();
-	comp_extractor.set_main_colour(pixel_hsv);
+	comp_extractor.set_main_colour(pixel_hsl);
-	pixel = HSVtoRGB(pixel_hsv);
+	pixel = HSLtoRGB(pixel_hsl);
-	pixel2 = HSVtoRGB(comp_extractor.extract_colour());
+	pixel2 = HSLtoRGB(comp_extractor.extract_colour());
 	
 	cout << "Main - ";
 	print_pixel(pixel);

main_colour_extractor.cpp

@@ -3,49 +3,21 @@
 #include <math.h>
 
 // CONSTRUCTORS
-MainColourExtractor::MainColourExtractor(double lightness_threshold,
+MainColourExtractor::MainColourExtractor(size_t h_levels, size_t s_levels,
-	size_t h_levels, size_t s_levels, size_t v_levels)
+	size_t l_levels)
-:ColourExtractor(h_levels, s_levels, v_levels),
+: ColourExtractor(h_levels, s_levels, l_levels)
-	m_lightness_threshold(lightness_threshold)
 {
 }
 
-// PRIVATE FUNCS
-double MainColourExtractor::calculate_lightness(struct ColourHSV hsv) const
-{
-	double result = 0.0;
-	struct ColourRGB rgb;
-
-	rgb = HSVtoRGB(hsv);
-	result = 0.299F * rgb.r + 0.587F * rgb.g + 0.114F * rgb.b;
-
-	return result;
-}
-
 // PROTECTED FUNCS
-size_t MainColourExtractor::evaluate_colour(struct ColourHSV hsv, double weight)
+size_t MainColourExtractor::evaluate_colour(struct ColourHSL hsl, double weight)
 	const
 {
 	size_t result = 0;
-	double lightness;
 
-	lightness = calculate_lightness(hsv);
+	result = static_cast<size_t>(round(1000.0 * pow(weight, 0.3) *
-	if (lightness >= m_lightness_threshold)
+		(hsl.s + 1.0 / m_s_levels) *
-	{
+		((1.0 - fabs(2 * hsl.l - 1.0)) * (1 - 1.0 / m_l_levels) + 1.0 / m_l_levels)));
-		result = static_cast<size_t>(round(1000.0 * (pow(weight, 0.3) +
-			0.009999999776482582) * hsv.v * (hsv.s + 0.1)));
-	}
 
 	return result;
 }
-
-// PUBLIC FUNCS
-double MainColourExtractor::get_lightness_threshold() const
-{
-	return m_lightness_threshold;
-}
-
-void MainColourExtractor::set_lightness_threshold(double value)
-{
-	m_lightness_threshold = value;
-}

main_colour_extractor.h

@@ -5,24 +5,13 @@
 
 class MainColourExtractor : public ColourExtractor
 {
-private:
-	// The minimum lightness a colour needs to have to be considered for
-	// evaluation
-	double m_lightness_threshold;
-
-	// Calculates the lightness of a colour
-	double calculate_lightness(struct ColourHSV hsv) const;
-
 protected:
 	// Implemented - Evaluates the given colour based on its weight
-	virtual size_t evaluate_colour(struct ColourHSV hsv, double weight) const;
+	virtual size_t evaluate_colour(struct ColourHSL hsv, double weight) const;
 
 public:
-	MainColourExtractor(double lightness_threshold = 0.2, size_t h_levels = 36,
+	MainColourExtractor(size_t h_levels = 36, size_t s_levels = 10,
-		size_t s_levels = 10, size_t v_levels = 10);
+		size_t l_levels = 10);
-
-	double get_lightness_threshold() const;
-	void set_lightness_threshold(double value);
 };
 
 #endif // MAIN_COLOUR_EXTRACTOR_H_