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| |
| #ifndef _BGFX_TOOLS_KEYSTOPLERP_HXX |
| #define _BGFX_TOOLS_KEYSTOPLERP_HXX |
| |
| #include <basegfx/numeric/ftools.hxx> |
| #include <vector> |
| |
| namespace com{ namespace sun{ namespace star{ namespace uno { |
| template<typename T> class Sequence; |
| }}}} |
| |
| namespace basegfx |
| { |
| namespace tools |
| { |
| /** Lerp in a vector of key stops |
| |
| This class holds a key stop vector and provides the |
| functionality to lerp inside it. Useful e.g. for |
| multi-stop gradients, or the SMIL key time activity. |
| |
| For those, given a global [0,1] lerp alpha, one need to |
| find the suitable bucket index from key stop vector, and |
| then calculate the relative alpha between the two buckets |
| found. |
| */ |
| class KeyStopLerp |
| { |
| public: |
| typedef std::pair<std::ptrdiff_t,double> ResultType; |
| |
| /** Create lerper with given vector of stops |
| |
| @param rKeyStops |
| |
| Vector of stops, must contain at least two elements |
| (though preferrably more, otherwise you probably don't |
| need key stop lerping in the first place). All |
| elements must be of monotonically increasing value. |
| */ |
| explicit KeyStopLerp( const std::vector<double>& rKeyStops ); |
| |
| /** Create lerper with given sequence of stops |
| |
| @param rKeyStops |
| |
| Sequence of stops, must contain at least two elements |
| (though preferrably more, otherwise you probably don't |
| need key stop lerping in the first place). All |
| elements must be of monotonically increasing value. |
| */ |
| explicit KeyStopLerp( const ::com::sun::star::uno::Sequence<double>& rKeyStops ); |
| |
| /** Find two nearest bucket index & interpolate |
| |
| @param fAlpha |
| Find bucket index i, with keyStops[i] < fAlpha <= |
| keyStops[i+1]. Return new alpha value in [0,1), |
| proportional to fAlpha's position between keyStops[i] |
| and keyStops[i+1] |
| */ |
| ResultType lerp(double fAlpha) const; |
| |
| private: |
| std::vector<double> maKeyStops; |
| mutable std::ptrdiff_t mnLastIndex; |
| }; |
| } |
| } |
| |
| #endif |