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      1 /*
      2  * Copyright (C) 2017 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 #ifndef MINIKIN_ANDROID_LINE_BREAKER_HELPERS_H
     18 #define MINIKIN_ANDROID_LINE_BREAKER_HELPERS_H
     19 
     20 #include <algorithm>
     21 
     22 #include "minikin/LineBreaker.h"
     23 
     24 namespace minikin {
     25 namespace android {
     26 
     27 class AndroidLineWidth : public LineWidth {
     28 public:
     29     AndroidLineWidth(float firstWidth, int32_t firstLineCount, float restWidth,
     30                      const std::vector<float>& indents, const std::vector<float>& leftPaddings,
     31                      const std::vector<float>& rightPaddings, int32_t indentsAndPaddingsOffset)
     32             : mFirstWidth(firstWidth),
     33               mFirstLineCount(firstLineCount),
     34               mRestWidth(restWidth),
     35               mIndents(indents),
     36               mLeftPaddings(leftPaddings),
     37               mRightPaddings(rightPaddings),
     38               mOffset(indentsAndPaddingsOffset) {}
     39 
     40     float getAt(size_t lineNo) const override {
     41         const float width = ((ssize_t)lineNo < (ssize_t)mFirstLineCount) ? mFirstWidth : mRestWidth;
     42         return std::max(0.0f, width - get(mIndents, lineNo));
     43     }
     44 
     45     float getMin() const override {
     46         // A simpler algorithm would have been simply looping until the larger of
     47         // mFirstLineCount and mIndents.size()-mOffset, but that does unnecessary calculations
     48         // when mFirstLineCount is large. Instead, we measure the first line, all the lines that
     49         // have an indent, and the first line after firstWidth ends and restWidth starts.
     50         float minWidth = std::min(getAt(0), getAt(mFirstLineCount));
     51         for (size_t lineNo = 1; lineNo + mOffset < mIndents.size(); lineNo++) {
     52             minWidth = std::min(minWidth, getAt(lineNo));
     53         }
     54         return minWidth;
     55     }
     56 
     57     float getLeftPaddingAt(size_t lineNo) const override { return get(mLeftPaddings, lineNo); }
     58 
     59     float getRightPaddingAt(size_t lineNo) const override { return get(mRightPaddings, lineNo); }
     60 
     61 private:
     62     float get(const std::vector<float>& vec, size_t lineNo) const {
     63         if (vec.empty()) {
     64             return 0;
     65         }
     66         const size_t index = lineNo + mOffset;
     67         if (index < vec.size()) {
     68             return vec[index];
     69         } else {
     70             return vec.back();
     71         }
     72     }
     73 
     74     const float mFirstWidth;
     75     const int32_t mFirstLineCount;
     76     const float mRestWidth;
     77     const std::vector<float>& mIndents;
     78     const std::vector<float>& mLeftPaddings;
     79     const std::vector<float>& mRightPaddings;
     80     const int32_t mOffset;
     81 };
     82 
     83 class StaticLayoutNative {
     84 public:
     85     StaticLayoutNative(BreakStrategy strategy, HyphenationFrequency frequency, bool isJustified,
     86                        std::vector<float>&& indents, std::vector<float>&& leftPaddings,
     87                        std::vector<float>&& rightPaddings)
     88             : mStrategy(strategy),
     89               mFrequency(frequency),
     90               mIsJustified(isJustified),
     91               mIndents(std::move(indents)),
     92               mLeftPaddings(std::move(leftPaddings)),
     93               mRightPaddings(std::move(rightPaddings)) {}
     94 
     95     LineBreakResult computeBreaks(const U16StringPiece& textBuf, const MeasuredText& measuredText,
     96                                   // Line width arguments
     97                                   float firstWidth, int32_t firstWidthLineCount, float restWidth,
     98                                   int32_t indentsOffset,
     99                                   // Tab stop arguments
    100                                   const int32_t* tabStops, int32_t tabStopSize,
    101                                   int32_t defaultTabStopWidth) const {
    102         AndroidLineWidth lineWidth(firstWidth, firstWidthLineCount, restWidth, mIndents,
    103                                    mLeftPaddings, mRightPaddings, indentsOffset);
    104         return breakIntoLines(textBuf, mStrategy, mFrequency, mIsJustified, measuredText, lineWidth,
    105                               TabStops(tabStops, tabStopSize, defaultTabStopWidth));
    106     }
    107 
    108     inline BreakStrategy getStrategy() const { return mStrategy; }
    109     inline HyphenationFrequency getFrequency() const { return mFrequency; }
    110     inline bool isJustified() const { return mIsJustified; }
    111 
    112 private:
    113     const BreakStrategy mStrategy;
    114     const HyphenationFrequency mFrequency;
    115     const bool mIsJustified;
    116     const std::vector<float> mIndents;
    117     const std::vector<float> mLeftPaddings;
    118     const std::vector<float> mRightPaddings;
    119 };
    120 
    121 }  // namespace android
    122 }  // namespace minikin
    123 
    124 #endif  // MINIKIN_ANDROID_LINE_BREAKER_HELPERS_H
    125