Add asADash entry point into SkPathEffect to allow extracting Dash info from PathEffects

BUG=skia:
R=bsalomon@google.com, reed@google.com

Author: egdaniel@google.com

Review URL: https://codereview.chromium.org/212103010

git-svn-id: http://skia.googlecode.com/svn/trunk@14297 2bbb7eff-a529-9590-31e7-b0007b416f81

2 files changed, 29 insertions, 1 deletions

diff --git a/include/core/SkPathEffect.h b/include/core/SkPathEffect.h
index 86ccf86a92..638287d07c 100644
--- a/include/core/SkPathEffect.h
+++ b/include/core/SkPathEffect.h
@@ -104,6 +104,33 @@ public:
                           const SkStrokeRec&, const SkMatrix&,
                           const SkRect* cullR) const;
 
+    /**
+     *  If the PathEffect can be represented as a dash pattern, asADash will return kDash_DashType
+     *  and None otherwise. If a non NULL info is passed in, the various DashInfo will be filled
+     *  in if the PathEffect can be a dash pattern. If passed in info has an fCount equal or
+     *  greater to that of the effect, it will memcpy the values of the dash intervals into the
+     *  info. Thus the general approach will be call asADash once with default info to get DashType
+     *  and fCount. If effect can be represented as a dash pattern, allocate space for the intervals
+     *  in info, then call asADash again with the same info and the intervals will get copied in.
+     */
+
+    enum DashType {
+        kNone_DashType, //!< ignores the info parameter
+        kDash_DashType, //!< fills in all of the info parameter
+    };
+
+    struct DashInfo {
+        DashInfo() : fIntervals(NULL), fCount(0), fPhase(0) {}
+
+        SkScalar*   fIntervals;         //!< Length of on/off intervals for dashed lines
+                                        //   Even values represent ons, and odds offs
+        int32_t     fCount;             //!< Number of intervals in the dash. Should be even number
+        SkScalar    fPhase;             //!< Offset into the dashed interval pattern
+                                        //   mod the sum of all intervals
+    };
+
+    virtual DashType asADash(DashInfo* info) const;
+
     SK_DEFINE_FLATTENABLE_TYPE(SkPathEffect)
 
 protected:
diff --git a/include/core/SkPicture.h b/include/core/SkPicture.h
index bf9ec4f8bb..996d85716e 100644
--- a/include/core/SkPicture.h
+++ b/include/core/SkPicture.h
@@ -324,13 +324,14 @@ protected:
     // V22: SK_PICT_FACTORY_TAG's size is now the chunk size in bytes
     // V23: SkPaint::FilterLevel became a real enum
     // V24: SkTwoPointConicalGradient now has fFlipped flag for gradient flipping
+    // V25: SkDashPathEffect now only writes phase and interval array when flattening
 
     // Note: If the picture version needs to be increased then please follow the
     // steps to generate new SKPs in (only accessible to Googlers): http://goo.gl/qATVcw
 
     // Only SKPs within the min/current picture version range (inclusive) can be read.
     static const uint32_t MIN_PICTURE_VERSION = 19;
-    static const uint32_t CURRENT_PICTURE_VERSION = 24;
+    static const uint32_t CURRENT_PICTURE_VERSION = 25;
 
     mutable uint32_t      fUniqueID;