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#include "colorscale.h"
#include <cmath>
const float EPSILON = 1e-3f;
Color::Color()
: Color(0, 0, 0, 255)
{
}
Color::Color(int r, int g, int b)
: Color(r, g, b, 255)
{
}
Color::Color(int r, int g, int b, int a)
: r(r)
, g(g)
, b(b)
, a(a)
{
}
Color::Color(float r, float g, float b)
: Color(r, g, b, 0.0f)
{
}
Color::Color(float r, float g, float b, float a)
: Color(static_cast<int>(round(255 * r)),
static_cast<int>(round(255 * g)),
static_cast<int>(round(255 * b)),
static_cast<int>(round(255 * a)))
{
}
void Color::getRgbF(float *r, float *g, float *b) const
{
*r = round(static_cast<float>(this->r) / 255.0f);
*g = round(static_cast<float>(this->g) / 255.0f);
*b = round(static_cast<float>(this->b) / 255.0f);
}
void Color::getRgbF(float *r, float *g, float *b, float *a) const
{
getRgbF(r, g, b);
*a = round(static_cast<float>(this->a) / 255.0f);
}
void Color::setRgb(int r, int g, int b)
{
setRgb(r, g, b, 255);
}
void Color::setRgb(int r, int g, int b, int a)
{
this->r = r;
this->g = g;
this->b = b;
this->a = a;
}
void Color::setRgbF(float r, float g, float b)
{
setRgb(static_cast<int>(round(255 * r)),
static_cast<int>(round(255 * g)),
static_cast<int>(round(255 * b)));
}
void Color::setRgbF(float r, float g, float b, float a)
{
setRgb(static_cast<int>(round(255 * r)),
static_cast<int>(round(255 * g)),
static_cast<int>(round(255 * b)),
static_cast<int>(round(255 * a)));
}
ColorScale::ColorScale(const Color &firstColor, const Color &lastColor)
: m_colors{{firstColor, lastColor}}
{
setExtents(0.0f, 1.0f);
}
ColorScale::ColorScale(std::initializer_list<Color> colors)
: m_colors(colors)
{
setExtents(0.0f, 1.0f);
}
ColorScale::ColorScale(const std::vector<Color> &colors)
: m_colors(colors)
{
setExtents(0.0f, 1.0f);
}
ColorScale::~ColorScale()
{
}
void ColorScale::setExtents(float min, float max)
{
if (min >= max) {
return;
}
m_min = min;
m_max = max;
}
Color ColorScale::lerp(const Color &c1, const Color &c2, float _t)
{
float r1, g1, b1, a1;
float r2, g2, b2, a2;
float t = _t;
c1.getRgbF(&r1, &g1, &b1, &a1);
c2.getRgbF(&r2, &g2, &b2, &a2);
Color color;
color.setRgbF(r1 * (1.0f - t) + r2 * t,
g1 * (1.0f - t) + g2 * t,
b1 * (1.0f - t) + b2 * t,
a1 * (1.0f - t) + a2 * t);
return color;
}
Color ColorScale::color(float t) const
{
if (t < m_min || t > m_max) {
return Color();
}
// normalize t
t = (t - m_min) / (m_max - m_min);
// two colors, use a simpler solution
if (m_colors.size() == 2) {
return lerp(m_colors.front(), m_colors.back(), t);
}
if (fabs(t - m_min) < EPSILON) {
return m_colors.front();
}
if (fabs(t - m_max) < EPSILON) {
return m_colors.back();
}
// find which colors in the scale are adjacent to ours
int i = int(t * m_colors.size());
int j = i + 1;
if (i >= m_colors.size() - 1) {
return Color(m_colors.back());
}
// normalize t between the two colors
float step = 1.0f / m_colors.size();
t = (t - i*step) / (j*step - i*step);
return lerp(m_colors[i], m_colors[j], t);
}
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