Method generate

dep/agg/include/agg_span_gradient.h:116–135

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        //--------------------------------------------------------------------
        void generate(color_type* span, int x, int y, unsigned len)
        {
            int dd = m_d2 - m_d1;
            if (dd < 1)
                dd = 1;
            m_interpolator->begin(x + 0.5, y + 0.5, len);
            do
            {
                m_interpolator->coordinates(&x, &y);
                int d = m_gradient_function->calculate(
                    x >> downscale_shift, y >> downscale_shift, m_d2);
                d = ((d - m_d1) * (int)m_color_function->size()) / dd;
                if (d < 0)
                    d = 0;
                if (d >= (int)m_color_function->size())
                    d = m_color_function->size() - 1;
                *span++ = (*m_color_function)[d];
                ++(*m_interpolator);
            } while (--len);
        }

    private:
        interpolator_type* m_interpolator;