Merge to XFA: Separate agg-authored code from fx-authored code.

Original Review URL: https://codereview.chromium.org/1152743007.
BUG=pdfium:166
R=brucedawson@chromium.org, thestig@chromium.org
TBR=brucedawson@chromium.org, thestig@chromium.org

Review URL: https://codereview.chromium.org/1186423003.

1 files changed, 125 insertions, 0 deletions

diff --git a/third_party/agg23/agg_clip_liang_barsky.h b/third_party/agg23/agg_clip_liang_barsky.h
new file mode 100644
index 0000000000..cfc4c91f60
--- /dev/null
+++ b/third_party/agg23/agg_clip_liang_barsky.h
@@ -0,0 +1,125 @@
+
+//----------------------------------------------------------------------------
+// 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"
+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 FX_FLOAT nearzero = 1e-30f;
+    FX_FLOAT deltax = (FX_FLOAT)(x2 - x1);
+    FX_FLOAT deltay = (FX_FLOAT)(y2 - y1);
+    unsigned np = 0;
+    if(deltax == 0) {
+        deltax = (x1 > clip_box.x1) ? -nearzero : nearzero;
+    }
+    FX_FLOAT xin, xout;
+    if(deltax > 0) {
+        xin  = (FX_FLOAT)clip_box.x1;
+        xout = (FX_FLOAT)clip_box.x2;
+    } else {
+        xin  = (FX_FLOAT)clip_box.x2;
+        xout = (FX_FLOAT)clip_box.x1;
+    }
+    FX_FLOAT tinx = FXSYS_Div(xin - x1, deltax);
+    if(deltay == 0) {
+        deltay = (y1 > clip_box.y1) ? -nearzero : nearzero;
+    }
+    FX_FLOAT yin, yout;
+    if(deltay > 0) {
+        yin  = (FX_FLOAT)clip_box.y1;
+        yout = (FX_FLOAT)clip_box.y2;
+    } else {
+        yin  = (FX_FLOAT)clip_box.y2;
+        yout = (FX_FLOAT)clip_box.y1;
+    }
+    FX_FLOAT tiny = FXSYS_Div(yin - y1, deltay);
+    FX_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) {
+            FX_FLOAT toutx = FXSYS_Div(xout - x1, deltax);
+            FX_FLOAT touty = FXSYS_Div(yout - y1, deltay);
+            FX_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 + FXSYS_Mul(deltay, tinx));
+                        } else {
+                            *x++ = (T)(x1 + FXSYS_Mul(deltax, tiny));
+                            *y++ = (T)yin;
+                        }
+                        ++np;
+                    }
+                    if(tout1 < 1.0f) {
+                        if(toutx < touty) {
+                            *x++ = (T)xout;
+                            *y++ = (T)(y1 + FXSYS_Mul(deltay, toutx));
+                        } else {
+                            *x++ = (T)(x1 + FXSYS_Mul(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;
+}
+}
+#endif