Move Dashing filterPath to a dashing utils file

From inside GrContext, we have a need to create an SkPath an original path and
some dashing info. We do not have access to the original path effect so we need
a way to make the FilterPath function accessible outside of the effect. So I moved
the core filterPath code (and all need helper functions) out of SkDashPathEffect
and created a SkDashPath in utils to store these helper functions.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/576dcdc793a762ec63fbecdbfd5768066b548fe5

Author: egdaniel@google.com

Review URL: https://codereview.chromium.org/314623004

1 files changed, 32 insertions, 0 deletions

diff --git a/src/utils/SkDashPathPriv.h b/src/utils/SkDashPathPriv.h
new file mode 100644
index 0000000000..94222a271a
--- /dev/null
+++ b/src/utils/SkDashPathPriv.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkDashPathPriv_DEFINED
+#define SkDashPathPriv_DEFINED
+
+#include "SkPathEffect.h"
+
+namespace SkDashPath {
+    /*
+     * Calculates the initialDashLength, initialDashIndex, and intervalLength based on the
+     * inputed phase and intervals. If adjustedPhase is passed in, then the phase will be
+     * adjusted to be between 0 and intervalLength. The result will be stored in adjustedPhase.
+     * If adjustedPhase is NULL then it is assumed phase is already between 0 and intervalLength
+     */
+    void CalcDashParameters(SkScalar phase, const SkScalar intervals[], int32_t count,
+                            SkScalar* initialDashLength, int32_t* initialDashIndex,
+                            SkScalar* intervalLength, SkScalar* adjustedPhase = NULL);
+
+    bool FilterDashPath(SkPath* dst, const SkPath& src, SkStrokeRec*, const SkRect*,
+                        const SkScalar aIntervals[], int32_t count, SkScalar initialDashLength,
+                        int32_t initialDashIndex, SkScalar intervalLength);
+    
+    bool FilterDashPath(SkPath* dst, const SkPath& src, SkStrokeRec*, const SkRect*,
+                        const SkPathEffect::DashInfo& info);
+}
+
+#endif