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, 77 insertions, 62 deletions

diff --git a/core/jni/android/graphics/Canvas.cpp b/core/jni/android/graphics/Canvas.cpp
index 4c7e762..b044271 100644
--- a/core/jni/android/graphics/Canvas.cpp
+++ b/core/jni/android/graphics/Canvas.cpp
@@ -31,6 +31,10 @@
 #include "SkMeshUtils.h"
 
 #include "unicode/ubidi.h"
+#include "unicode/ushape.h"
+
+// temporary for debugging
+#include <utils/Log.h>
 
 #define TIME_DRAWx
 
@@ -764,19 +768,43 @@ public:
                              indices, indexCount, *paint);
     }
 
-    static void shapeRtlText__(const jchar* text, jsize len, jsize start, jsize count, jchar* shaped) {
-        // fake shaping, just reverse the text
-        for (int i = 0; i < count; ++i) {
-            shaped[i] = text[start + count - 1 - i];
+    /**
+     * @context the text context
+     * @start the start of the text to render
+     * @count the length of the text to render, start + count  must be <= len
+     * @contextCount the length of the context
+     * @shaped where to put the shaped text, must have capacity for count uchars
+     * @return the length of the shaped text, or -1 if error
+     */
+    static int shapeRtlText__(const jchar* context, jsize start, jsize count, jsize contextCount,
+                              jchar* shaped, UErrorCode &status) {
+        jchar buffer[contextCount];
+
+        // We'd rather use harfbuzz here.  Use character based shaping for now.
+
+        // Use fixed length since we need to keep start and count valid
+        u_shapeArabic(context, contextCount, buffer, contextCount,
+                       U_SHAPE_LENGTH_FIXED_SPACES_NEAR |
+                       U_SHAPE_TEXT_DIRECTION_LOGICAL | U_SHAPE_LETTERS_SHAPE |
+                       U_SHAPE_X_LAMALEF_SUB_ALTERNATE, &status);
+
+        if (!U_SUCCESS(status)) {
+            return 0;
         }
-        // fix surrogate pairs, if any
-        for (int i = 1; i < count; ++i) {
-            if (shaped[i] >= 0xd800 && shaped[i] < 0xdc00 && 
-                    shaped[i-1] >= 0xdc00 && shaped[i-1] < 0xe000) {
-                jchar c = shaped[i]; shaped[i] = shaped[i-1]; shaped[i-1] = c;
-                i += 1;
+
+        // trim out 0xffff following ligatures, if any
+        int end = 0;
+        for (int i = start, e = start + count; i < e; ++i) {
+            if (buffer[i] == 0xffff) {
+              continue;
             }
+            buffer[end++] = buffer[i];
         }
+        count = end;
+        // LOG(LOG_INFO, "CSRTL", "start %d count %d ccount %d\n", start, count, contextCount);
+        ubidi_writeReverse(buffer, count, shaped, count, UBIDI_DO_MIRRORING | UBIDI_OUTPUT_REVERSE
+                           | UBIDI_KEEP_BASE_COMBINING, &status);
+        return count;
     }
 
     static void drawText__(JNIEnv* env, SkCanvas* canvas, const jchar* text, jsize len,
@@ -784,7 +812,7 @@ public:
         SkScalar x_ = SkFloatToScalar(x);
         SkScalar y_ = SkFloatToScalar(y);
 
-	SkPaint::Align horiz = paint->getTextAlign();
+        SkPaint::Align horiz = paint->getTextAlign();
 
         bool needBidi = (flags == kBidi_RTL) || (flags == kBidi_Default_RTL);
         if (!needBidi && flags < kBidi_Force_LTR) {
@@ -815,7 +843,7 @@ public:
                     case kBidi_Default_LTR: lineDir = UBIDI_DEFAULT_LTR; break;
                     case kBidi_Default_RTL: lineDir = UBIDI_DEFAULT_RTL; break;
                     }
-                      
+
                     UBiDi* bidi = ubidi_open();
                     ubidi_setPara(bidi, text, len, lineDir, NULL, &status);
                     if (U_SUCCESS(status)) {
@@ -843,9 +871,9 @@ public:
                             }
                         }
                         ubidi_close(bidi);
-                    } 
+                    }
                 } else {
-                    shapeRtlText__(text, len, 0, len, shaped);
+                  len = shapeRtlText__(text, 0, len, len, shaped, status);
                 }
             }
         }
@@ -886,7 +914,7 @@ public:
             free(shaped);
         }
     }
-    
+
     static void drawText___CIIFFIPaint(JNIEnv* env, jobject, SkCanvas* canvas,
                                       jcharArray text, int index, int count,
                                       jfloat x, jfloat y, int flags, SkPaint* paint) {
@@ -894,72 +922,60 @@ public:
         drawText__(env, canvas, textArray + index, count, x, y, flags, paint);
         env->ReleaseCharArrayElements(text, textArray, JNI_ABORT);
     }
- 
+
     static void drawText__StringIIFFIPaint(JNIEnv* env, jobject,
-                                          SkCanvas* canvas, jstring text, 
+                                          SkCanvas* canvas, jstring text,
                                           int start, int end,
                                           jfloat x, jfloat y, int flags, SkPaint* paint) {
         const jchar* textArray = env->GetStringChars(text, NULL);
         drawText__(env, canvas, textArray + start, end - start, x, y, flags, paint);
         env->ReleaseStringChars(text, textArray);
     }
-    
-    // Draws a unidirectional run of text.  Does not run bidi, but does reorder the
-    // text and run shaping (or will, when we have harfbuzz support).
-    static void drawTextRun__(JNIEnv* env, SkCanvas* canvas, const jchar* chars, int len, 
-                              int start, int count,
+
+    // Draws a unidirectional run of text.
+    static void drawTextRun__(JNIEnv* env, SkCanvas* canvas, const jchar* chars,
+                              jint start, jint count, jint contextCount,
                               jfloat x, jfloat y, int flags, SkPaint* paint) {
 
         SkScalar x_ = SkFloatToScalar(x);
         SkScalar y_ = SkFloatToScalar(y);
 
         uint8_t rtl = flags & 0x1;
-
-        UErrorCode status = U_ZERO_ERROR;
-        jchar *shaped = NULL;
         if (rtl) {
-            shaped = (jchar *)malloc(count * sizeof(jchar));
-            if (!shaped) {
-                status = U_MEMORY_ALLOCATION_ERROR;
+            jchar context[contextCount];
+            UErrorCode status = U_ZERO_ERROR;
+            count = shapeRtlText__(chars, start, count, contextCount, context, status);
+            if (U_SUCCESS(status)) {
+                canvas->drawText(context, count << 1, x_, y_, *paint);
             } else {
-                shapeRtlText__(chars, len, start, count, shaped);
+                doThrowIAE(env, "shaping error");
             }
-        }
-
-        if (!U_SUCCESS(status)) {
-            char buffer[30];
-            sprintf(buffer, "DrawTextRun error %d", status);
-            doThrowIAE(env, buffer);
         } else {
-            if (shaped) {
-                canvas->drawText(shaped, count << 1, x_, y_, *paint);
-            } else {
-                canvas->drawText(chars + start, count << 1, x_, y_, *paint);
-            }
-        }
-
-        if (shaped) {
-            free(shaped);
+            canvas->drawText(chars + start, count << 1, x_, y_, *paint);
         }
     }
 
-    static void drawTextRun___CIIFFIPaint(
+    static void drawTextRun___CIIIIFFIPaint(
         JNIEnv* env, jobject, SkCanvas* canvas, jcharArray text, int index,
-        int count, jfloat x, jfloat y, int flags, SkPaint* paint) {
+        int count, int contextIndex, int contextCount,
+        jfloat x, jfloat y, int flags, SkPaint* paint) {
 
-        jint len = env->GetArrayLength(text);
         jchar* chars = env->GetCharArrayElements(text, NULL);
-        drawTextRun__(env, canvas, chars, len, index, count, x, y, flags, paint);
+        drawTextRun__(env, canvas, chars + contextIndex, index - contextIndex,
+                      count, contextCount, x, y, flags, paint);
         env->ReleaseCharArrayElements(text, chars, JNI_ABORT);
     }
 
-    static void drawTextRun__StringIIFFIPaint(
-        JNIEnv* env, jobject obj, SkCanvas* canvas, jstring text, int start,
-        int end, jfloat x, jfloat y, int flags, SkPaint* paint) {
+    static void drawTextRun__StringIIIIFFIPaint(
+        JNIEnv* env, jobject obj, SkCanvas* canvas, jstring text, jint start,
+        jint end, jint contextStart, jint contextEnd,
+        jfloat x, jfloat y, jint flags, SkPaint* paint) {
 
-        jint len = env->GetStringLength(text);
+        jint count = end - start;
+        jint contextCount = contextEnd - contextStart;
         const jchar* chars = env->GetStringChars(text, NULL);
-        drawTextRun__(env, canvas, chars, len, start, end - start, x, y, flags, paint);
+        drawTextRun__(env, canvas, chars + contextStart, start - contextStart,
+                      count, contextCount, x, y, flags, paint);
         env->ReleaseStringChars(text, chars);
     }
 
@@ -985,7 +1001,7 @@ public:
         }
         delete[] posPtr;
     }
- 
+
     static void drawPosText__String_FPaint(JNIEnv* env, jobject,
                                            SkCanvas* canvas, jstring text,
                                            jfloatArray pos, SkPaint* paint) {
@@ -1008,7 +1024,7 @@ public:
         }
         delete[] posPtr;
     }
- 
+
     static void drawTextOnPath___CIIPathFFPaint(JNIEnv* env, jobject,
                         SkCanvas* canvas, jcharArray text, int index, int count,
                 SkPath* path, jfloat hOffset, jfloat vOffset, SkPaint* paint) {
@@ -1018,7 +1034,7 @@ public:
                     SkFloatToScalar(hOffset), SkFloatToScalar(vOffset), *paint);
         env->ReleaseCharArrayElements(text, textArray, 0);
     }
- 
+
     static void drawTextOnPath__StringPathFFPaint(JNIEnv* env, jobject,
                             SkCanvas* canvas, jstring text, SkPath* path,
                             jfloat hOffset, jfloat vOffset, SkPaint* paint) {
@@ -1028,7 +1044,7 @@ public:
                     SkFloatToScalar(hOffset), SkFloatToScalar(vOffset), *paint);
         env->ReleaseStringChars(text, text_);
     }
- 
+
     static bool getClipBounds(JNIEnv* env, jobject, SkCanvas* canvas,
                               jobject bounds) {
         SkRect   r;
@@ -1121,7 +1137,6 @@ static JNINativeMethod gCanvasMethods[] = {
         (void*) SkCanvasGlue::drawBitmapRR},
     {"native_drawBitmap", "(I[IIIFFIIZI)V",
     (void*)SkCanvasGlue::drawBitmapArray},
-    
     {"nativeDrawBitmapMatrix", "(IIII)V",
         (void*)SkCanvasGlue::drawBitmapMatrix},
     {"nativeDrawBitmapMesh", "(IIII[FI[III)V",
@@ -1132,10 +1147,10 @@ static JNINativeMethod gCanvasMethods[] = {
         (void*) SkCanvasGlue::drawText___CIIFFIPaint},
     {"native_drawText","(ILjava/lang/String;IIFFII)V",
         (void*) SkCanvasGlue::drawText__StringIIFFIPaint},
-    {"native_drawTextRun","(I[CIIFFII)V",
-        (void*) SkCanvasGlue::drawTextRun___CIIFFIPaint},
-    {"native_drawTextRun","(ILjava/lang/String;IIFFII)V",
-        (void*) SkCanvasGlue::drawTextRun__StringIIFFIPaint},
+    {"native_drawTextRun","(I[CIIIIFFII)V",
+        (void*) SkCanvasGlue::drawTextRun___CIIIIFFIPaint},
+    {"native_drawTextRun","(ILjava/lang/String;IIIIFFII)V",
+        (void*) SkCanvasGlue::drawTextRun__StringIIIIFFIPaint},
     {"native_drawPosText","(I[CII[FI)V",
         (void*) SkCanvasGlue::drawPosText___CII_FPaint},
     {"native_drawPosText","(ILjava/lang/String;[FI)V",