| |
| //---------------------------------------------------------------------------- |
| // Anti-Grain Geometry - Version 2.3 |
| // 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 |
| //---------------------------------------------------------------------------- |
| // |
| // Liang-Barsky clipping |
| // |
| //---------------------------------------------------------------------------- |
| #ifndef AGG_CLIP_LIANG_BARSKY_INCLUDED |
| #define AGG_CLIP_LIANG_BARSKY_INCLUDED |
| #include "agg_basics.h" |
| #include "core/fxcrt/numerics/safe_math.h" |
| namespace pdfium |
| { |
| namespace agg |
| { |
| template<class T> |
| inline unsigned clipping_flags(T x, T y, const rect_base<T>& clip_box) |
| { |
| return (x > clip_box.x2) | |
| ((y > clip_box.y2) << 1) | |
| ((x < clip_box.x1) << 2) | |
| ((y < clip_box.y1) << 3); |
| } |
| template<class T> |
| inline unsigned clip_liang_barsky(T x1, T y1, T x2, T y2, |
| const rect_base<T>& clip_box, |
| T* x, T* y) |
| { |
| const float nearzero = 1e-30f; |
| |
| pdfium::CheckedNumeric<float> width = x2; |
| width -= x1; |
| if (!width.IsValid()) |
| return 0; |
| pdfium::CheckedNumeric<float> height = y2; |
| height -= y1; |
| if (!height.IsValid()) |
| return 0; |
| |
| float deltax = width.ValueOrDefault(0); |
| float deltay = height.ValueOrDefault(0); |
| unsigned np = 0; |
| if(deltax == 0) { |
| deltax = (x1 > clip_box.x1) ? -nearzero : nearzero; |
| } |
| float xin, xout; |
| if(deltax > 0) { |
| xin = (float)clip_box.x1; |
| xout = (float)clip_box.x2; |
| } else { |
| xin = (float)clip_box.x2; |
| xout = (float)clip_box.x1; |
| } |
| float tinx = (xin - x1) / deltax; |
| if(deltay == 0) { |
| deltay = (y1 > clip_box.y1) ? -nearzero : nearzero; |
| } |
| float yin, yout; |
| if(deltay > 0) { |
| yin = (float)clip_box.y1; |
| yout = (float)clip_box.y2; |
| } else { |
| yin = (float)clip_box.y2; |
| yout = (float)clip_box.y1; |
| } |
| float tiny = (yin - y1) / deltay; |
| float tin1, tin2; |
| if (tinx < tiny) { |
| tin1 = tinx; |
| tin2 = tiny; |
| } else { |
| tin1 = tiny; |
| tin2 = tinx; |
| } |
| if(tin1 <= 1.0f) { |
| if(0 < tin1) { |
| *x++ = (T)xin; |
| *y++ = (T)yin; |
| ++np; |
| } |
| if(tin2 <= 1.0f) { |
| float toutx = (xout - x1) / deltax; |
| float touty = (yout - y1) / deltay; |
| float tout1 = (toutx < touty) ? toutx : touty; |
| if (tin2 > 0 || tout1 > 0) { |
| if(tin2 <= tout1) { |
| if(tin2 > 0) { |
| if(tinx > tiny) { |
| *x++ = (T)xin; |
| *y++ = (T)(y1 + (deltay * tinx)); |
| } else { |
| *x++ = (T)(x1 + (deltax * tiny)); |
| *y++ = (T)yin; |
| } |
| ++np; |
| } |
| if(tout1 < 1.0f) { |
| if(toutx < touty) { |
| *x++ = (T)xout; |
| *y++ = (T)(y1 + (deltay * toutx)); |
| } else { |
| *x++ = (T)(x1 + (deltax * touty)); |
| *y++ = (T)yout; |
| } |
| } else { |
| *x++ = x2; |
| *y++ = y2; |
| } |
| ++np; |
| } else { |
| if(tinx > tiny) { |
| *x++ = (T)xin; |
| *y++ = (T)yout; |
| } else { |
| *x++ = (T)xout; |
| *y++ = (T)yin; |
| } |
| ++np; |
| } |
| } |
| } |
| } |
| return np; |
| } |
| } |
| } // namespace pdfium |
| #endif |