108 lines
3.1 KiB
C
108 lines
3.1 KiB
C
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//----------------------------------------------------------------------------
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// Anti-Grain Geometry - Version 2.2
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// Copyright (C) 2002-2004 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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//
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// color type gray8
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//
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//----------------------------------------------------------------------------
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#ifndef AGG_GRAY8_INCLUDED
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#define AGG_GRAY8_INCLUDED
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#include "agg_basics.h"
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#include "agg_color_rgba.h"
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#include "agg_color_rgba8.h"
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namespace agg
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{
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//===================================================================gray8
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struct gray8
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{
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int8u v;
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int8u a;
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//--------------------------------------------------------------------
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gray8() {}
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//--------------------------------------------------------------------
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gray8(unsigned v_, unsigned a_=255) :
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v(int8u(v_)), a(int8u(a_)) {}
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//--------------------------------------------------------------------
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gray8(const rgba& c) :
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v(int8u((0.299*c.r + 0.587*c.g + 0.114*c.b) * 255.0 + 0.5)),
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a(int8u(c.a*255.0)) {}
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//--------------------------------------------------------------------
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gray8(const rgba8& c) :
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v((c.r*77 + c.g*150 + c.b*29) >> 8),
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a(c.a) {}
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//--------------------------------------------------------------------
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void clear()
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{
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v = a = 0;
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}
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//--------------------------------------------------------------------
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const gray8& transparent()
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{
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a = 0;
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return *this;
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}
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//--------------------------------------------------------------------
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void opacity(double a_)
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{
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if(a_ < 0.0) a_ = 0.0;
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if(a_ > 1.0) a_ = 1.0;
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a = int8u(a_ * 255.0);
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}
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//--------------------------------------------------------------------
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double opacity() const
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{
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return double(a) / 255.0;
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}
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//--------------------------------------------------------------------
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gray8 gradient(gray8 c, double k) const
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{
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gray8 ret;
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int ik = int(k * 256);
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ret.v = int8u(int(v) + (((int(c.v) - int(v)) * ik) >> 8));
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ret.a = int8u(int(a) + (((int(c.a) - int(a)) * ik) >> 8));
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return ret;
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}
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//--------------------------------------------------------------------
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gray8 pre() const
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{
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return gray8((v*a) >> 8, a);
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}
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//--------------------------------------------------------------------
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static gray8 no_color() { return gray8(0,0); }
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};
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}
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#endif
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