Move shaping to native.

Add internal API (getTextRunAdvances) to Paint, use when measuring.
Add internal API (getTextRunCursor) to Paint, use when determining
valid cursor positions.

Remove java-level shaping code.  Remove 'prep' code in TextLine
(except for replacement text) since shaping now is done on the fly as
needed in native.

Provide explicit shaping context bounds to internal text measuring,
cursor movement, and rendering APIs.

Update for to changes in external API in ushape.h.

Change-Id: I146958b624802ce8553125e5c3c6c03031bc9608

1 files changed, 65 insertions, 21 deletions

diff --git a/core/java/android/text/SpannableStringBuilder.java b/core/java/android/text/SpannableStringBuilder.java
index 756317932d06..56f130284464 100644
--- a/core/java/android/text/SpannableStringBuilder.java
+++ b/core/java/android/text/SpannableStringBuilder.java
@@ -1055,35 +1055,27 @@ implements CharSequence, GetChars, Spannable, Editable, Appendable,
         }
     }
 
+
     /**
      * Don't call this yourself -- exists for Canvas to use internally.
      * {@hide}
      */
     public void drawTextRun(Canvas c, int start, int end,
-                         float x, float y, int flags, Paint p) {
+            int contextStart, int contextEnd,
+            float x, float y, int flags, Paint p) {
         checkRange("drawTextRun", start, end);
 
-        // Assume context requires no more than 8 chars on either side.
-        // This is ample, only decomposed U+FDFA falls into this
-        // category, and no one should put a style break within it 
-        // anyway.
-        int cstart = start - 8;
-        if (cstart < 0) {
-            cstart = 0;
-        }
-        int cend = end + 8;
-        int max = length();
-        if (cend > max) {
-            cend = max;
-        }
-        if (cend <= mGapStart) {
-            c.drawTextRun(mText, start, end - start, x, y, flags, p);
-        } else if (cstart >= mGapStart) {
-            c.drawTextRun(mText, start + mGapLength, end - start, x, y, flags, p);
+        int contextLen = contextEnd - contextStart;
+        int len = end - start;
+        if (contextEnd <= mGapStart) {
+            c.drawTextRun(mText, start, len, contextStart, contextLen, x, y, flags, p);
+        } else if (contextStart >= mGapStart) {
+            c.drawTextRun(mText, start + mGapLength, len, contextStart + mGapLength,
+                    contextLen, x, y, flags, p);
         } else {
-            char[] buf = TextUtils.obtain(cend - cstart);
-            getChars(cstart, cend, buf, 0);
-            c.drawTextRun(buf, start - cstart, end - start, x, y, flags, p);
+            char[] buf = TextUtils.obtain(contextLen);
+            getChars(contextStart, contextEnd, buf, 0);
+            c.drawTextRun(buf, start - contextStart, len, 0, contextLen, x, y, flags, p);
             TextUtils.recycle(buf);
         }
     }
@@ -1137,6 +1129,58 @@ implements CharSequence, GetChars, Spannable, Editable, Appendable,
         return ret;
     }
 
+    /**
+     * Don't call this yourself -- exists for Paint to use internally.
+     * {@hide}
+     */
+    public float getTextRunAdvances(int start, int end, int contextStart, int contextEnd, int flags,
+            float[] advances, int advancesPos, Paint p) {
+
+        float ret;
+
+        int contextLen = contextEnd - contextStart;
+        int len = end - start;
+
+        if (end <= mGapStart) {
+            ret = p.getTextRunAdvances(mText, start, len, contextStart, contextLen,
+                    flags, advances, advancesPos);
+        } else if (start >= mGapStart) {
+            ret = p.getTextRunAdvances(mText, start + mGapLength, len,
+                    contextStart + mGapLength, contextLen, flags, advances, advancesPos);
+        } else {
+            char[] buf = TextUtils.obtain(contextLen);
+            getChars(contextStart, contextEnd, buf, 0);
+            ret = p.getTextRunAdvances(buf, start - contextStart, len,
+                    0, contextLen, flags, advances, advancesPos);
+            TextUtils.recycle(buf);
+        }
+
+        return ret;
+    }
+
+    public int getTextRunCursor(int contextStart, int contextEnd, int flags, int offset,
+            int cursorOpt, Paint p) {
+
+        int ret;
+
+        int contextLen = contextEnd - contextStart;
+        if (contextEnd <= mGapStart) {
+            ret = p.getTextRunCursor(mText, contextStart, contextLen,
+                    flags, offset, cursorOpt);
+        } else if (contextStart >= mGapStart) {
+            ret = p.getTextRunCursor(mText, contextStart + mGapLength, contextLen,
+                    flags, offset + mGapLength, cursorOpt);
+        } else {
+            char[] buf = TextUtils.obtain(contextLen);
+            getChars(contextStart, contextEnd, buf, 0);
+            ret = p.getTextRunCursor(buf, 0, contextLen,
+                    flags, offset - contextStart, cursorOpt) + contextStart;
+            TextUtils.recycle(buf);
+        }
+
+        return ret;
+    }
+
     // Documentation from interface
     public void setFilters(InputFilter[] filters) {
         if (filters == null) {