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#define LOG_TAG "TextLayout"
18
19#include "TextLayout.h"
20#include "TextLayoutCache.h"
21
22#include <android_runtime/AndroidRuntime.h>
23
24#include "SkTemplates.h"
25#include "unicode/ubidi.h"
26#include "unicode/ushape.h"
27#include <utils/Log.h>
28
29namespace android {
30
31// Returns true if we might need layout.  If bidiFlags force LTR, assume no layout, if
32// bidiFlags indicate there probably is RTL, assume we do, otherwise scan the text
33// looking for a character >= the first RTL character in unicode and assume we do if
34// we find one.
35bool TextLayout::needsLayout(const jchar* text, jint len, jint bidiFlags) {
36    if (bidiFlags == kBidi_Force_LTR) {
37        return false;
38    }
39    if ((bidiFlags == kBidi_RTL) || (bidiFlags == kBidi_Default_RTL) ||
40            bidiFlags == kBidi_Force_RTL) {
41        return true;
42    }
43    for (int i = 0; i < len; ++i) {
44        if (text[i] >= UNICODE_FIRST_RTL_CHAR) {
45            return true;
46        }
47    }
48    return false;
49}
50
51// Draws or gets the path of a paragraph of text on a single line, running bidi and shaping.
52// This will draw if canvas is not null, otherwise path must be non-null and it will create
53// a path representing the text that would have been drawn.
54void TextLayout::handleText(SkPaint *paint, const jchar* text, jsize len,
55                            jint bidiFlags, jfloat x, jfloat y, SkPath *path) {
56    sp<TextLayoutValue> value = TextLayoutEngine::getInstance().getValue(paint,
57            text, 0, len, len, bidiFlags);
58    if (value == NULL) {
59        return ;
60    }
61    SkScalar x_ = SkFloatToScalar(x);
62    SkScalar y_ = SkFloatToScalar(y);
63    // Beware: this needs Glyph encoding (already done on the Paint constructor)
64    paint->getTextPath(value->getGlyphs(), value->getGlyphsCount() * 2, x_, y_, path);
65}
66
67void TextLayout::getTextRunAdvances(SkPaint* paint, const jchar* chars, jint start,
68                                    jint count, jint contextCount, jint dirFlags,
69                                    jfloat* resultAdvances, jfloat* resultTotalAdvance) {
70    sp<TextLayoutValue> value = TextLayoutEngine::getInstance().getValue(paint,
71            chars, start, count, contextCount, dirFlags);
72    if (value == NULL) {
73        return ;
74    }
75    if (resultAdvances) {
76        memcpy(resultAdvances, value->getAdvances(), value->getAdvancesCount() * sizeof(jfloat));
77    }
78    if (resultTotalAdvance) {
79        *resultTotalAdvance = value->getTotalAdvance();
80    }
81}
82
83void TextLayout::getTextPath(SkPaint *paint, const jchar *text, jsize len,
84                             jint bidiFlags, jfloat x, jfloat y, SkPath *path) {
85    handleText(paint, text, len, bidiFlags, x, y, path);
86}
87
88
89void TextLayout::drawTextOnPath(SkPaint* paint, const jchar* text, int count,
90                                int bidiFlags, jfloat hOffset, jfloat vOffset,
91                                SkPath* path, SkCanvas* canvas) {
92
93    SkScalar h_ = SkFloatToScalar(hOffset);
94    SkScalar v_ = SkFloatToScalar(vOffset);
95
96    sp<TextLayoutValue> value = TextLayoutEngine::getInstance().getValue(paint,
97            text, 0, count, count, bidiFlags);
98    if (value == NULL) {
99        return;
100    }
101
102    // Beware: this needs Glyph encoding (already done on the Paint constructor)
103    canvas->drawTextOnPathHV(value->getGlyphs(), value->getGlyphsCount() * 2, *path, h_, v_, *paint);
104}
105
106}
107