418 lines
14 KiB
C++
418 lines
14 KiB
C++
//----------------------------------------------------------------------------
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// Anti-Grain Geometry - Version 2.4
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// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
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//
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// Permission to copy, use, modify, sell and distribute this software
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// is granted provided this copyright notice appears in all copies.
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// This software is provided "as is" without express or implied
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// warranty, and with no claim as to its suitability for any purpose.
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//
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//----------------------------------------------------------------------------
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// Contact: mcseem@antigrain.com
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// mcseemagg@yahoo.com
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// http://www.antigrain.com
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//----------------------------------------------------------------------------
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#ifndef AGG_SPAN_GRADIENT_INCLUDED
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#define AGG_SPAN_GRADIENT_INCLUDED
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#include <math.h>
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#include <stdlib.h>
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#include <string.h>
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#include "agg_basics.h"
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#include "agg_math.h"
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#include "agg_array.h"
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namespace agg
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{
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enum gradient_subpixel_scale_e
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{
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gradient_subpixel_shift = 4, //-----gradient_subpixel_shift
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gradient_subpixel_scale = 1 << gradient_subpixel_shift, //-----gradient_subpixel_scale
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gradient_subpixel_mask = gradient_subpixel_scale - 1 //-----gradient_subpixel_mask
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};
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//==========================================================span_gradient
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template<class ColorT,
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class Interpolator,
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class GradientF,
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class ColorF>
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class span_gradient
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{
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public:
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typedef Interpolator interpolator_type;
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typedef ColorT color_type;
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enum downscale_shift_e
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{
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downscale_shift = interpolator_type::subpixel_shift -
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gradient_subpixel_shift
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};
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//--------------------------------------------------------------------
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span_gradient() {}
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//--------------------------------------------------------------------
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span_gradient(interpolator_type& inter,
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const GradientF& gradient_function,
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const ColorF& color_function,
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double d1, double d2) :
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m_interpolator(&inter),
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m_gradient_function(&gradient_function),
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m_color_function(&color_function),
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m_d1(iround(d1 * gradient_subpixel_scale)),
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m_d2(iround(d2 * gradient_subpixel_scale))
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{}
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//--------------------------------------------------------------------
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interpolator_type& interpolator() { return *m_interpolator; }
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const GradientF& gradient_function() const { return *m_gradient_function; }
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const ColorF& color_function() const { return *m_color_function; }
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double d1() const { return double(m_d1) / gradient_subpixel_scale; }
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double d2() const { return double(m_d2) / gradient_subpixel_scale; }
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//--------------------------------------------------------------------
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void interpolator(interpolator_type& i) { m_interpolator = &i; }
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void gradient_function(const GradientF& gf) { m_gradient_function = &gf; }
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void color_function(const ColorF& cf) { m_color_function = &cf; }
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void d1(double v) { m_d1 = iround(v * gradient_subpixel_scale); }
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void d2(double v) { m_d2 = iround(v * gradient_subpixel_scale); }
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//--------------------------------------------------------------------
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void prepare() {}
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//--------------------------------------------------------------------
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void generate(color_type* span, int x, int y, unsigned len)
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{
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int dd = m_d2 - m_d1;
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if(dd < 1) dd = 1;
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m_interpolator->begin(x+0.5, y+0.5, len);
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do
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{
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m_interpolator->coordinates(&x, &y);
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int d = m_gradient_function->calculate(x >> downscale_shift,
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y >> downscale_shift, m_d2);
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d = ((d - m_d1) * (int)m_color_function->size()) / dd;
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if(d < 0) d = 0;
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if(d >= (int)m_color_function->size()) d = m_color_function->size() - 1;
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*span++ = (*m_color_function)[d];
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++(*m_interpolator);
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}
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while(--len);
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}
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private:
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interpolator_type* m_interpolator;
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const GradientF* m_gradient_function;
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const ColorF* m_color_function;
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int m_d1;
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int m_d2;
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};
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//=====================================================gradient_linear_color
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template<class ColorT>
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struct gradient_linear_color
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{
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typedef ColorT color_type;
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gradient_linear_color() {}
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gradient_linear_color(const color_type& c1, const color_type& c2,
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unsigned size = 256) :
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m_c1(c1), m_c2(c2), m_size(size) {}
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unsigned size() const { return m_size; }
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color_type operator [] (unsigned v) const
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{
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return m_c1.gradient(m_c2, double(v) / double(m_size - 1));
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}
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void colors(const color_type& c1, const color_type& c2, unsigned size = 256)
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{
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m_c1 = c1;
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m_c2 = c2;
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m_size = size;
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}
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color_type m_c1;
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color_type m_c2;
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unsigned m_size;
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};
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//==========================================================gradient_circle
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class gradient_circle
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{
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// Actually the same as radial. Just for compatibility
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public:
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static AGG_INLINE int calculate(int x, int y, int)
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{
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return int(fast_sqrt(x*x + y*y));
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}
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};
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//==========================================================gradient_radial
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class gradient_radial
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{
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public:
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static AGG_INLINE int calculate(int x, int y, int)
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{
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return int(fast_sqrt(x*x + y*y));
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}
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};
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//========================================================gradient_radial_d
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class gradient_radial_d
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{
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public:
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static AGG_INLINE int calculate(int x, int y, int)
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{
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return uround(sqrt(double(x)*double(x) + double(y)*double(y)));
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}
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};
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//====================================================gradient_radial_focus
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class gradient_radial_focus
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{
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public:
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//---------------------------------------------------------------------
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gradient_radial_focus() :
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m_radius(100 * gradient_subpixel_scale),
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m_focus_x(0),
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m_focus_y(0)
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{
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update_values();
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}
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//---------------------------------------------------------------------
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gradient_radial_focus(double r, double fx, double fy) :
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m_radius (iround(r * gradient_subpixel_scale)),
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m_focus_x(iround(fx * gradient_subpixel_scale)),
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m_focus_y(iround(fy * gradient_subpixel_scale))
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{
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update_values();
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}
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//---------------------------------------------------------------------
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void init(double r, double fx, double fy)
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{
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m_radius = iround(r * gradient_subpixel_scale);
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m_focus_x = iround(fx * gradient_subpixel_scale);
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m_focus_y = iround(fy * gradient_subpixel_scale);
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update_values();
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}
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//---------------------------------------------------------------------
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double radius() const { return double(m_radius) / gradient_subpixel_scale; }
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double focus_x() const { return double(m_focus_x) / gradient_subpixel_scale; }
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double focus_y() const { return double(m_focus_y) / gradient_subpixel_scale; }
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//---------------------------------------------------------------------
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int calculate(int x, int y, int) const
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{
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double solution_x;
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double solution_y;
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// Special case to avoid divide by zero or very near zero
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//---------------------------------
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if(x == iround(m_focus_x))
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{
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solution_x = m_focus_x;
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solution_y = 0.0;
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solution_y += (y > m_focus_y) ? m_trivial : -m_trivial;
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}
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else
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{
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// Slope of the focus-current line
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//-------------------------------
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double slope = double(y - m_focus_y) / double(x - m_focus_x);
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// y-intercept of that same line
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//--------------------------------
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double yint = double(y) - (slope * x);
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// Use the classical quadratic formula to calculate
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// the intersection point
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//--------------------------------
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double a = (slope * slope) + 1;
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double b = 2 * slope * yint;
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double c = yint * yint - m_radius2;
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double det = sqrt((b * b) - (4.0 * a * c));
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solution_x = -b;
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// Choose the positive or negative root depending
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// on where the X coord lies with respect to the focus.
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solution_x += (x < m_focus_x) ? -det : det;
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solution_x /= 2.0 * a;
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// Calculating of Y is trivial
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solution_y = (slope * solution_x) + yint;
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}
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// Calculate the percentage (0...1) of the current point along the
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// focus-circumference line and return the normalized (0...d) value
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//-------------------------------
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solution_x -= double(m_focus_x);
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solution_y -= double(m_focus_y);
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double int_to_focus = solution_x * solution_x + solution_y * solution_y;
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double cur_to_focus = double(x - m_focus_x) * double(x - m_focus_x) +
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double(y - m_focus_y) * double(y - m_focus_y);
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return iround(sqrt(cur_to_focus / int_to_focus) * m_radius);
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}
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private:
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//---------------------------------------------------------------------
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void update_values()
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{
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// For use in the quadratic equation
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//-------------------------------
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m_radius2 = double(m_radius) * double(m_radius);
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double dist = sqrt(double(m_focus_x) * double(m_focus_x) +
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double(m_focus_y) * double(m_focus_y));
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// Test if distance from focus to center is greater than the radius
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// For the sake of assurance factor restrict the point to be
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// no further than 99% of the radius.
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//-------------------------------
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double r = m_radius * 0.99;
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if(dist > r)
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{
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// clamp focus to radius
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// x = r cos theta, y = r sin theta
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//------------------------
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double a = atan2(double(m_focus_y), double(m_focus_x));
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m_focus_x = iround(r * cos(a));
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m_focus_y = iround(r * sin(a));
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}
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// Calculate the solution to be used in the case where x == focus_x
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//------------------------------
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m_trivial = sqrt(m_radius2 - (m_focus_x * m_focus_x));
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}
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int m_radius;
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int m_focus_x;
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int m_focus_y;
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double m_radius2;
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double m_trivial;
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};
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//==============================================================gradient_x
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class gradient_x
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{
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public:
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static int calculate(int x, int, int) { return x; }
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};
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//==============================================================gradient_y
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class gradient_y
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{
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public:
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static int calculate(int, int y, int) { return y; }
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};
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//========================================================gradient_diamond
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class gradient_diamond
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{
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public:
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static AGG_INLINE int calculate(int x, int y, int)
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{
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int ax = abs(x);
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int ay = abs(y);
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return ax > ay ? ax : ay;
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}
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};
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//=============================================================gradient_xy
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class gradient_xy
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{
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public:
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static AGG_INLINE int calculate(int x, int y, int d)
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{
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return abs(x) * abs(y) / d;
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}
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};
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//========================================================gradient_sqrt_xy
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class gradient_sqrt_xy
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{
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public:
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static AGG_INLINE int calculate(int x, int y, int)
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{
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return fast_sqrt(abs(x) * abs(y));
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}
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};
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//==========================================================gradient_conic
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class gradient_conic
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{
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public:
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static AGG_INLINE int calculate(int x, int y, int d)
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{
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return uround(fabs(atan2(double(y), double(x))) * double(d) / pi);
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}
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};
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//=================================================gradient_repeat_adaptor
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template<class GradientF> class gradient_repeat_adaptor
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{
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public:
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gradient_repeat_adaptor(const GradientF& gradient) :
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m_gradient(&gradient) {}
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AGG_INLINE int calculate(int x, int y, int d) const
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{
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int ret = m_gradient->calculate(x, y, d) % d;
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if(ret < 0) ret += d;
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return ret;
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}
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private:
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const GradientF* m_gradient;
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};
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//================================================gradient_reflect_adaptor
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template<class GradientF> class gradient_reflect_adaptor
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{
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public:
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gradient_reflect_adaptor(const GradientF& gradient) :
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m_gradient(&gradient) {}
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AGG_INLINE int calculate(int x, int y, int d) const
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{
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int d2 = d << 1;
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int ret = m_gradient->calculate(x, y, d) % d2;
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if(ret < 0) ret += d2;
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if(ret >= d) ret = d2 - ret;
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return ret;
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}
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private:
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const GradientF* m_gradient;
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};
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}
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#endif
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