1 #ifndef __NR_FILTER_UTILS_H__
2 #define __NR_FILTER_UTILS_H__
4 /** \file
5 * filter utils. Definition of functions needed by several filters.
6 *
7 * Authors:
8 * Jean-Rene Reinhard <jr@komite.net>
9 *
10 * Copyright (C) 2007 authors
11 *
12 * Released under GNU GPL, read the file 'COPYING' for more information
13 */
15 #include "round.h"
17 /* Shouldn't these be inlined? */
18 namespace Inkscape {
19 namespace Filters {
21 /**
22 * Clamps an integer value to a value between 0 and 255. Needed by filters where
23 * rendering computations can lead to component values out of bound.
24 *
25 * \return 0 if the value is smaller than 0, 255 if it is greater 255, else v
26 * \param v the value to clamp
27 */
28 int clamp(int const val);
30 /**
31 * Clamps an integer value to a value between 0 and 255^3.
32 *
33 * \return 0 if the value is smaller than 0, 255^3 (16581375) if it is greater than 255^3, else v
34 * \param v the value to clamp
35 */
36 int clamp3(int const val);
38 /**
39 * Macro to use the clamp function with double inputs and unsigned char output
40 */
41 #define CLAMP_D_TO_U8(v) (unsigned char) clamp((int)round((v)))
43 /**
44 * Clamps an integer to a value between 0 and alpha. Useful when handling
45 * images with premultiplied alpha, as setting some of RGB channels
46 * to a value bigger than alpha confuses the alpha blending in Inkscape
47 * \return 0 if val is negative, alpha if val is bigger than alpha, val otherwise
48 * \param val the value to clamp
49 * \param alpha the maximum value to clamp to
50 */
51 int clamp_alpha(int const val, int const alpha);
53 } /* namespace Filters */
54 } /* namespace Inkscape */
56 #endif /* __NR_FILTER_UTILS_H__ */
57 /*
58 Local Variables:
59 mode:c++
60 c-file-style:"stroustrup"
61 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
62 indent-tabs-mode:nil
63 fill-column:99
64 End:
65 */
66 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :