b9c7e1bdd9
While here, do not interpolate style properties that are not transitionable. The previous behavior was to switch from old to new value halfway through the transition; now the new value is used immediately, as in JS.
79 lines
1.5 KiB
C++
79 lines
1.5 KiB
C++
#ifndef MBGL_UTIL_TRANSITION
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#define MBGL_UTIL_TRANSITION
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#include <mbgl/util/noncopyable.hpp>
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#include <mbgl/util/time.hpp>
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#include <mbgl/style/types.hpp>
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namespace mbgl {
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namespace util {
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class transition : private noncopyable {
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public:
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enum state {
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running,
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complete
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};
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inline transition(timestamp start, timestamp duration)
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: start(start),
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duration(duration) {}
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inline float progress(timestamp now) const {
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if (duration == 0) return 1;
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if (start > now) return 0;
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return (float)(now - start) / duration;
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}
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virtual state update(timestamp now) const = 0;
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virtual ~transition();
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protected:
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const timestamp start, duration;
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};
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template <typename T>
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class ease_transition : public transition {
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public:
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ease_transition(T from, T to, T& value, timestamp start, timestamp duration)
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: transition(start, duration),
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from(from),
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to(to),
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value(value) {}
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state update(timestamp now) const;
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private:
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const T from, to;
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T& value;
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};
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template <typename T>
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class timeout : public transition {
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public:
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timeout(T final_value, T& value, timestamp start, timestamp duration)
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: transition(start, duration),
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final_value(final_value),
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value(value) {}
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state update(timestamp now) const {
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if (progress(now) >= 1) {
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value = final_value;
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return complete;
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} else {
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return running;
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}
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}
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private:
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const T final_value;
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T& value;
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};
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}
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}
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#endif
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