You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
95 lines
3.7 KiB
95 lines
3.7 KiB
//---------------------------------------------------------------------------- |
|
// 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
|
|
|