grab from latest android
git-svn-id: http://skia.googlecode.com/svn/trunk@27 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/utils/SkCullPoints.cpp b/src/utils/SkCullPoints.cpp
new file mode 100644
index 0000000..23d00b6
--- /dev/null
+++ b/src/utils/SkCullPoints.cpp
@@ -0,0 +1,168 @@
+/* libs/graphics/effects/SkCullPoints.cpp
+**
+** Copyright 2006, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+** http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+
+#include "SkCullPoints.h"
+#include "Sk64.h"
+
+static bool cross_product_is_neg(const SkIPoint& v, int dx, int dy)
+{
+#if 0
+ return v.fX * dy - v.fY * dx < 0;
+#else
+ Sk64 tmp0, tmp1;
+
+ tmp0.setMul(v.fX, dy);
+ tmp1.setMul(dx, v.fY);
+ tmp0.sub(tmp1);
+ return tmp0.isNeg();
+#endif
+}
+
+bool SkCullPoints::sect_test(int x0, int y0, int x1, int y1) const
+{
+ const SkIRect& r = fR;
+
+ if (x0 < r.fLeft && x1 < r.fLeft ||
+ x0 > r.fRight && x1 > r.fRight ||
+ y0 < r.fTop && y1 < r.fTop ||
+ y0 > r.fBottom && y1 > r.fBottom)
+ return false;
+
+ // since the crossprod test is a little expensive, check for easy-in cases first
+ if (r.contains(x0, y0) || r.contains(x1, y1))
+ return true;
+
+ // At this point we're not sure, so we do a crossprod test
+ SkIPoint vec;
+ const SkIPoint* rAsQuad = fAsQuad;
+
+ vec.set(x1 - x0, y1 - y0);
+ bool isNeg = cross_product_is_neg(vec, x0 - rAsQuad[0].fX, y0 - rAsQuad[0].fY);
+ for (int i = 1; i < 4; i++) {
+ if (cross_product_is_neg(vec, x0 - rAsQuad[i].fX, y0 - rAsQuad[i].fY) != isNeg)
+ {
+ return true;
+ }
+ }
+ return false; // we didn't intersect
+}
+
+static void toQuad(const SkIRect& r, SkIPoint quad[4])
+{
+ SkASSERT(quad);
+
+ quad[0].set(r.fLeft, r.fTop);
+ quad[1].set(r.fRight, r.fTop);
+ quad[2].set(r.fRight, r.fBottom);
+ quad[3].set(r.fLeft, r.fBottom);
+}
+
+SkCullPoints::SkCullPoints()
+{
+ SkIRect r;
+ r.setEmpty();
+ this->reset(r);
+}
+
+SkCullPoints::SkCullPoints(const SkIRect& r)
+{
+ this->reset(r);
+}
+
+void SkCullPoints::reset(const SkIRect& r)
+{
+ fR = r;
+ toQuad(fR, fAsQuad);
+ fPrevPt.set(0, 0);
+ fPrevResult = kNo_Result;
+}
+
+void SkCullPoints::moveTo(int x, int y)
+{
+ fPrevPt.set(x, y);
+ fPrevResult = kNo_Result; // so we trigger a movetolineto later
+}
+
+SkCullPoints::LineToResult SkCullPoints::lineTo(int x, int y, SkIPoint line[])
+{
+ SkASSERT(line != NULL);
+
+ LineToResult result = kNo_Result;
+ int x0 = fPrevPt.fX;
+ int y0 = fPrevPt.fY;
+
+ // need to upgrade sect_test to chop the result
+ // and to correctly return kLineTo_Result when the result is connected
+ // to the previous call-out
+ if (this->sect_test(x0, y0, x, y))
+ {
+ line[0].set(x0, y0);
+ line[1].set(x, y);
+
+ if (fPrevResult != kNo_Result && fPrevPt.equals(x0, y0))
+ result = kLineTo_Result;
+ else
+ result = kMoveToLineTo_Result;
+ }
+
+ fPrevPt.set(x, y);
+ fPrevResult = result;
+
+ return result;
+}
+
+/////////////////////////////////////////////////////////////////////////////////////////////////
+
+#include "SkPath.h"
+
+SkCullPointsPath::SkCullPointsPath()
+ : fCP(), fPath(NULL)
+{
+}
+
+SkCullPointsPath::SkCullPointsPath(const SkIRect& r, SkPath* dst)
+ : fCP(r), fPath(dst)
+{
+}
+
+void SkCullPointsPath::reset(const SkIRect& r, SkPath* dst)
+{
+ fCP.reset(r);
+ fPath = dst;
+}
+
+void SkCullPointsPath::moveTo(int x, int y)
+{
+ fCP.moveTo(x, y);
+}
+
+void SkCullPointsPath::lineTo(int x, int y)
+{
+ SkIPoint pts[2];
+
+ switch (fCP.lineTo(x, y, pts)) {
+ case SkCullPoints::kMoveToLineTo_Result:
+ fPath->moveTo(SkIntToScalar(pts[0].fX), SkIntToScalar(pts[0].fY));
+ // fall through to the lineto case
+ case SkCullPoints::kLineTo_Result:
+ fPath->lineTo(SkIntToScalar(pts[1].fX), SkIntToScalar(pts[1].fY));
+ break;
+ default:
+ break;
+ }
+}
+