nr-filter-utils.h revision d9a7c806ee7f408ddb61ff4f233c9d96111ee2b5
#ifndef __NR_FILTER_UTILS_H__
#define __NR_FILTER_UTILS_H__
/** \file
* filter utils. Definition of functions needed by several filters.
*
* Authors:
* Jean-Rene Reinhard <jr@komite.net>
*
* Copyright (C) 2007 authors
*
* Released under GNU GPL, read the file 'COPYING' for more information
*/
#include "round.h"
/* Shouldn't these be inlined? */
namespace Inkscape {
namespace Filters {
/**
* Clamps an integer value to a value between 0 and 255. Needed by filters where
* rendering computations can lead to component values out of bound.
*
* \return 0 if the value is smaller than 0, 255 if it is greater 255, else v
* \param v the value to clamp
*/
int clamp(int const val);
/**
* Clamps an integer value to a value between 0 and 255^3.
*
* \return 0 if the value is smaller than 0, 255^3 (16581375) if it is greater than 255^3, else v
* \param v the value to clamp
*/
int clamp3(int const val);
/**
* Macro to use the clamp function with double inputs and unsigned char output
*/
#define CLAMP_D_TO_U8(v) (unsigned char) clamp((int)round((v)))
/**
* Clamps an integer to a value between 0 and alpha. Useful when handling
* images with premultiplied alpha, as setting some of RGB channels
* to a value bigger than alpha confuses the alpha blending in Inkscape
* \return 0 if val is negative, alpha if val is bigger than alpha, val otherwise
* \param val the value to clamp
* \param alpha the maximum value to clamp to
*/
int clamp_alpha(int const val, int const alpha);
} /* namespace Filters */
} /* namespace Inkscape */
#endif /* __NR_FILTER_UTILS_H__ */
/*
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End:
*/
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