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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "jni.h"
     18 
     19 #include "SkCanvas.h"
     20 #include "SkPaint.h"
     21 #include "unicode/utypes.h"
     22 
     23 #include "TextLayoutCache.h"
     24 
     25 namespace android {
     26 
     27 #define UNICODE_NOT_A_CHAR              0xffff
     28 #define UNICODE_ZWSP                    0x200b
     29 #define UNICODE_FIRST_LOW_SURROGATE     0xdc00
     30 #define UNICODE_FIRST_HIGH_SURROGATE    0xd800
     31 #define UNICODE_FIRST_PRIVATE_USE       0xe000
     32 #define UNICODE_FIRST_RTL_CHAR          0x0590
     33 
     34 /*
     35  * Temporary buffer size
     36  */
     37 #define CHAR_BUFFER_SIZE 80
     38 
     39 /**
     40  * Turn on for using the Cache
     41  */
     42 #define USE_TEXT_LAYOUT_CACHE 1
     43 
     44 enum {
     45     kBidi_LTR = 0,
     46     kBidi_RTL = 1,
     47     kBidi_Default_LTR = 2,
     48     kBidi_Default_RTL = 3,
     49     kBidi_Force_LTR = 4,
     50     kBidi_Force_RTL = 5,
     51 
     52     kBidi_Mask = 0x7
     53 };
     54 
     55 enum {
     56     kDirection_LTR = 0,
     57     kDirection_RTL = 1,
     58 
     59     kDirection_Mask = 0x1
     60 };
     61 
     62 class TextLayout {
     63 public:
     64 
     65     /*
     66      * Draws a unidirectional run of text.
     67      */
     68     static void drawTextRun(SkPaint* paint, const jchar* chars,
     69                             jint start, jint count, jint contextCount,
     70                             int dirFlags, jfloat x, jfloat y, SkCanvas* canvas);
     71 
     72     static void getTextRunAdvances(SkPaint* paint, const jchar* chars, jint start,
     73                                    jint count, jint contextCount, jint dirFlags,
     74                                    jfloat* resultAdvances, jfloat* resultTotalAdvance);
     75 
     76     static void getTextRunAdvancesICU(SkPaint* paint, const jchar* chars, jint start,
     77                                    jint count, jint contextCount, jint dirFlags,
     78                                    jfloat* resultAdvances, jfloat& resultTotalAdvance);
     79 
     80     static void drawText(SkPaint* paint, const jchar* text, jsize len,
     81                          jint bidiFlags, jfloat x, jfloat y, SkCanvas* canvas);
     82 
     83     static void getTextPath(SkPaint* paint, const jchar* text, jsize len,
     84                             jint bidiFlags, jfloat x, jfloat y, SkPath* path);
     85 
     86     static void drawTextOnPath(SkPaint* paint, const jchar* text, jsize len,
     87                                int bidiFlags, jfloat hOffset, jfloat vOffset,
     88                                SkPath* path, SkCanvas* canvas);
     89 
     90     static bool prepareText(SkPaint* paint, const jchar* text, jsize len, jint bidiFlags,
     91         const jchar** outText, int32_t* outBytes, jchar** outBuffer);
     92 
     93     static bool prepareRtlTextRun(const jchar* context, jsize start, jsize& count,
     94         jsize contextCount, jchar* shaped);
     95 
     96 
     97 private:
     98     static bool needsLayout(const jchar* text, jint len, jint bidiFlags);
     99     static int shapeRtlText(const jchar* context, jsize start, jsize count, jsize contextCount,
    100                             jchar* shaped, UErrorCode& status);
    101     static jint layoutLine(const jchar* text, jint len, jint flags, int &dir, jchar* buffer,
    102                            UErrorCode &status);
    103     static void handleText(SkPaint* paint, const jchar* text, jsize len,
    104                            int bidiFlags, jfloat x, jfloat y, SkCanvas* canvas, SkPath* path);
    105 
    106     static void computeAdvancesWithICU(SkPaint* paint, const UChar* chars,
    107             size_t start, size_t count, size_t contextCount, int dirFlags,
    108             jfloat* outAdvances, jfloat* outTotalAdvance);
    109 };
    110 } // namespace android
    111