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#ifndef MBGL_UTIL_TRANSITION
#define MBGL_UTIL_TRANSITION
#include <mbgl/util/noncopyable.hpp>
#include <mbgl/util/time.hpp>
#include <mbgl/style/types.hpp>
namespace mbgl {
namespace util {
class transition : private noncopyable {
public:
enum state {
running,
complete
};
inline transition(timestamp start, timestamp duration)
: start(start),
duration(duration) {}
inline float progress(timestamp now) const {
if (duration == 0) return 1;
if (start > now) return 0;
return (float)(now - start) / duration;
}
virtual state update(timestamp now) const = 0;
virtual ~transition();
protected:
double interpolateDouble(double from, double to, double t) const;
float interpolateFloat(float from, float to, double t) const;
Color interpolateColor(Color from, Color to, double t) const;
std::array<float, 2> interpolateFloatArray(std::array<float, 2> from, std::array<float, 2> to, double t) const;
protected:
const timestamp start, duration;
};
template <typename T>
class ease_transition : public transition {
public:
ease_transition(T from, T to, T& value, timestamp start, timestamp duration)
: transition(start, duration),
from(from),
to(to),
value(value) {}
state update(timestamp now) const;
private:
const T from, to;
T& value;
};
template <typename T>
class timeout : public transition {
public:
timeout(T final_value, T& value, timestamp start, timestamp duration)
: transition(start, duration),
final_value(final_value),
value(value) {}
state update(timestamp now) const {
if (progress(now) >= 1) {
value = final_value;
return complete;
} else {
return running;
}
}
private:
const T final_value;
T& value;
};
}
}
#endif
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