96 lines
3.7 KiB
C++
96 lines
3.7 KiB
C++
//----------------------------------------------------------------------------
|
|
// Anti-Grain Geometry - Version 2.4
|
|
// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
|
|
//
|
|
// Permission to copy, use, modify, sell and distribute this software
|
|
// is granted provided this copyright notice appears in all copies.
|
|
// This software is provided "as is" without express or implied
|
|
// warranty, and with no claim as to its suitability for any purpose.
|
|
//
|
|
//----------------------------------------------------------------------------
|
|
// Contact: mcseem@antigrain.com
|
|
// mcseemagg@yahoo.com
|
|
// http://www.antigrain.com
|
|
//----------------------------------------------------------------------------
|
|
//
|
|
// class gamma_spline
|
|
//
|
|
//----------------------------------------------------------------------------
|
|
|
|
#ifndef AGG_GAMMA_SPLINE_INCLUDED
|
|
#define AGG_GAMMA_SPLINE_INCLUDED
|
|
|
|
#include "agg_basics.h"
|
|
#include "agg_bspline.h"
|
|
|
|
namespace agg
|
|
{
|
|
|
|
//------------------------------------------------------------------------
|
|
// Class-helper for calculation gamma-correction arrays. A gamma-correction
|
|
// array is an array of 256 unsigned chars that determine the actual values
|
|
// of Anti-Aliasing for each pixel coverage value from 0 to 255. If all the
|
|
// values in the array are equal to its index, i.e. 0,1,2,3,... there's
|
|
// no gamma-correction. Class agg::polyfill allows you to use custom
|
|
// gamma-correction arrays. You can calculate it using any approach, and
|
|
// class gamma_spline allows you to calculate almost any reasonable shape
|
|
// of the gamma-curve with using only 4 values - kx1, ky1, kx2, ky2.
|
|
//
|
|
// kx2
|
|
// +----------------------------------+
|
|
// | | | . |
|
|
// | | | . | ky2
|
|
// | | . ------|
|
|
// | | . |
|
|
// | | . |
|
|
// |----------------.|----------------|
|
|
// | . | |
|
|
// | . | |
|
|
// |-------. | |
|
|
// ky1 | . | | |
|
|
// | . | | |
|
|
// +----------------------------------+
|
|
// kx1
|
|
//
|
|
// Each value can be in range [0...2]. Value 1.0 means one quarter of the
|
|
// bounding rectangle. Function values() calculates the curve by these
|
|
// 4 values. After calling it one can get the gamma-array with call gamma().
|
|
// Class also supports the vertex source interface, i.e rewind() and
|
|
// vertex(). It's made for convinience and used in class gamma_ctrl.
|
|
// Before calling rewind/vertex one must set the bounding box
|
|
// box() using pixel coordinates.
|
|
//------------------------------------------------------------------------
|
|
|
|
class gamma_spline
|
|
{
|
|
public:
|
|
gamma_spline();
|
|
|
|
void values(double kx1, double ky1, double kx2, double ky2);
|
|
const unsigned char* gamma() const { return m_gamma; }
|
|
double y(double x) const;
|
|
void values(double* kx1, double* ky1, double* kx2, double* ky2) const;
|
|
void box(double x1, double y1, double x2, double y2);
|
|
|
|
void rewind(unsigned);
|
|
unsigned vertex(double* x, double* y);
|
|
|
|
private:
|
|
unsigned char m_gamma[256];
|
|
double m_x[4];
|
|
double m_y[4];
|
|
bspline m_spline;
|
|
double m_x1;
|
|
double m_y1;
|
|
double m_x2;
|
|
double m_y2;
|
|
double m_cur_x;
|
|
};
|
|
|
|
|
|
|
|
|
|
}
|
|
|
|
#endif
|