grab from latest android
git-svn-id: http://skia.googlecode.com/svn/trunk@27 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/effects/SkDashPathEffect.cpp b/src/effects/SkDashPathEffect.cpp
new file mode 100644
index 0000000..48581b5
--- /dev/null
+++ b/src/effects/SkDashPathEffect.cpp
@@ -0,0 +1,178 @@
+/* libs/graphics/effects/SkDashPathEffect.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 "SkDashPathEffect.h"
+#include "SkBuffer.h"
+#include "SkPathMeasure.h"
+
+static inline int is_even(int x)
+{
+ return (~x) << 31;
+}
+
+static SkScalar FindFirstInterval(const SkScalar intervals[], SkScalar phase, int32_t* index)
+{
+ int i;
+
+ for (i = 0; phase > intervals[i]; i++)
+ phase -= intervals[i];
+ *index = i;
+ return intervals[i] - phase;
+}
+
+SkDashPathEffect::SkDashPathEffect(const SkScalar intervals[], int count, SkScalar phase, bool scaleToFit)
+ : fScaleToFit(scaleToFit)
+{
+ SkASSERT(intervals);
+ SkASSERT(count > 1 && SkAlign2(count) == count);
+
+ fIntervals = (SkScalar*)sk_malloc_throw(sizeof(SkScalar) * count);
+ fCount = count;
+
+ SkScalar len = 0;
+ for (int i = 0; i < count; i++)
+ {
+ SkASSERT(intervals[i] >= 0);
+ fIntervals[i] = intervals[i];
+ len += intervals[i];
+ }
+ fIntervalLength = len;
+
+ if (len > 0) // we don't handle 0 length dash arrays
+ {
+ if (phase < 0)
+ {
+ phase = -phase;
+ if (phase > len)
+ phase = SkScalarMod(phase, len);
+ phase = len - phase;
+ }
+ else if (phase >= len)
+ phase = SkScalarMod(phase, len);
+
+ SkASSERT(phase >= 0 && phase < len);
+ fInitialDashLength = FindFirstInterval(intervals, phase, &fInitialDashIndex);
+
+ SkASSERT(fInitialDashLength >= 0);
+ SkASSERT(fInitialDashIndex >= 0 && fInitialDashIndex < fCount);
+ }
+ else
+ fInitialDashLength = -1; // signal bad dash intervals
+}
+
+SkDashPathEffect::~SkDashPathEffect()
+{
+ sk_free(fIntervals);
+}
+
+bool SkDashPathEffect::filterPath(SkPath* dst, const SkPath& src, SkScalar* width)
+{
+ // we do nothing if the src wants to be filled, or if our dashlength is 0
+ if (*width < 0 || fInitialDashLength < 0)
+ return false;
+
+ SkPathMeasure meas(src, false);
+ const SkScalar* intervals = fIntervals;
+
+ do {
+ bool skipFirstSegment = meas.isClosed();
+ bool addedSegment = false;
+ SkScalar length = meas.getLength();
+ int index = fInitialDashIndex;
+ SkScalar scale = SK_Scalar1;
+
+ if (fScaleToFit)
+ {
+ if (fIntervalLength >= length)
+ scale = SkScalarDiv(length, fIntervalLength);
+ else
+ {
+ SkScalar div = SkScalarDiv(length, fIntervalLength);
+ int n = SkScalarFloor(div);
+ scale = SkScalarDiv(length, n * fIntervalLength);
+ }
+ }
+
+ SkScalar distance = 0;
+ SkScalar dlen = SkScalarMul(fInitialDashLength, scale);
+
+ while (distance < length)
+ {
+ SkASSERT(dlen >= 0);
+ addedSegment = false;
+ if (is_even(index) && dlen > 0 && !skipFirstSegment)
+ {
+ addedSegment = true;
+ meas.getSegment(distance, distance + dlen, dst, true);
+ }
+ distance += dlen;
+
+ // clear this so we only respect it the first time around
+ skipFirstSegment = false;
+
+ // wrap around our intervals array if necessary
+ index += 1;
+ SkASSERT(index <= fCount);
+ if (index == fCount)
+ index = 0;
+
+ // fetch our next dlen
+ dlen = SkScalarMul(intervals[index], scale);
+ }
+
+ // extend if we ended on a segment and we need to join up with the (skipped) initial segment
+ if (meas.isClosed() && is_even(fInitialDashIndex) && fInitialDashLength > 0)
+ meas.getSegment(0, SkScalarMul(fInitialDashLength, scale), dst, !addedSegment);
+ } while (meas.nextContour());
+ return true;
+}
+
+SkFlattenable::Factory SkDashPathEffect::getFactory()
+{
+ return fInitialDashLength < 0 ? NULL : CreateProc;
+}
+
+void SkDashPathEffect::flatten(SkFlattenableWriteBuffer& buffer)
+{
+ SkASSERT(fInitialDashLength >= 0);
+
+ buffer.write32(fCount);
+ buffer.write32(fInitialDashIndex);
+ buffer.writeScalar(fInitialDashLength);
+ buffer.writeScalar(fIntervalLength);
+ buffer.write32(fScaleToFit);
+ buffer.writeMul4(fIntervals, fCount * sizeof(fIntervals[0]));
+}
+
+SkFlattenable* SkDashPathEffect::CreateProc(SkFlattenableReadBuffer& buffer)
+{
+ return SkNEW_ARGS(SkDashPathEffect, (buffer));
+}
+
+SkDashPathEffect::SkDashPathEffect(SkFlattenableReadBuffer& buffer)
+{
+ fCount = buffer.readS32();
+ fInitialDashIndex = buffer.readS32();
+ fInitialDashLength = buffer.readScalar();
+ fIntervalLength = buffer.readScalar();
+ fScaleToFit = (buffer.readS32() != 0);
+
+ fIntervals = (SkScalar*)sk_malloc_throw(sizeof(SkScalar) * fCount);
+ buffer.read(fIntervals, fCount * sizeof(fIntervals[0]));
+}
+
+