icuSources/samples/layout/paragraph.cpp

   1 /*
   2  *******************************************************************************
   3  *
   4  *   © 2016 and later: Unicode, Inc. and others.
   5  *   License & terms of use: http://www.unicode.org/copyright.html#License
   6  *
   7  *******************************************************************************
   8  *******************************************************************************
   9  *
  10  *   Copyright (C) 1999-2015, International Business Machines
  11  *   Corporation and others.  All Rights Reserved.
  12  *
  13  *******************************************************************************
  14  *   file name:  Paragraph.cpp
  15  *
  16  *   created on: 09/06/2000
  17  *   created by: Eric R. Mader
  18  */
  19
  20 #include "unicode/utypes.h"
  21 #include "unicode/uchar.h"
  22 #include "unicode/ubidi.h"
  23 #include "unicode/ustring.h"
  24
  25 #include "layout/ParagraphLayout.h"
  26
  27 #include "RenderingSurface.h"
  28
  29 #include "paragraph.h"
  30 #include "UnicodeReader.h"
  31
  32 #define MARGIN 10
  33 #define LINE_GROW 32
  34 #define PARA_GROW 8
  35
  36 #define CH_LF 0x000A
  37 #define CH_CR 0x000D
  38 #define CH_LSEP 0x2028
  39 #define CH_PSEP 0x2029
  40
  41 static LEUnicode *skipLineEnd(LEUnicode *ptr)
  42 {
  43     if (ptr[0] == CH_CR && ptr[1] == CH_LF) {
  44         ptr += 1;
  45     }
  46
  47     return ptr + 1;
  48 }
  49
  50 static le_int32 findRun(const RunArray *runArray, le_int32 offset)
  51 {
  52     le_int32 runCount = runArray->getCount();
  53
  54     for (le_int32 run = 0; run < runCount; run += 1) {
  55         if (runArray->getLimit(run) > offset) {
  56             return run;
  57         }
  58     }
  59
  60     return -1;
  61 }
  62
  63 static void subsetFontRuns(const FontRuns *fontRuns, le_int32 start, le_int32 limit, FontRuns *sub)
  64 {
  65     le_int32 startRun = findRun(fontRuns, start);
  66     le_int32 endRun   = findRun(fontRuns, limit - 1);
  67
  68     sub->reset();
  69
  70     for (le_int32 run = startRun; run <= endRun; run += 1) {
  71         const LEFontInstance *runFont = fontRuns->getFont(run);
  72         le_int32 runLimit = fontRuns->getLimit(run) - start;
  73
  74         if (run == endRun) {
  75             runLimit = limit - start;
  76         }
  77
  78         sub->add(runFont, runLimit);
  79     }
  80 }
  81
  82 Paragraph::Paragraph(const LEUnicode chars[], int32_t charCount, const FontRuns *fontRuns, LEErrorCode &status)
  83   : fParagraphLayout(NULL), fParagraphCount(0), fParagraphMax(PARA_GROW), fParagraphGrow(PARA_GROW),
  84     fLineCount(0), fLinesMax(LINE_GROW), fLinesGrow(LINE_GROW), fLines(NULL), fChars(NULL),
  85     fLineHeight(-1), fAscent(-1), fWidth(-1), fHeight(-1), fParagraphLevel(UBIDI_DEFAULT_LTR)
  86 {
  87     static const LEUnicode separators[] = {CH_LF, CH_CR, CH_LSEP, CH_PSEP, 0x0000};
  88
  89         if (LE_FAILURE(status)) {
  90                 return;
  91         }
  92
  93     le_int32 ascent  = 0;
  94     le_int32 descent = 0;
  95     le_int32 leading = 0;
  96
  97         LocaleRuns *locales = NULL;
  98     FontRuns fr(0);
  99
 100     fLines = LE_NEW_ARRAY(const ParagraphLayout::Line *, fLinesMax);
 101     fParagraphLayout = LE_NEW_ARRAY(ParagraphLayout *, fParagraphMax);
 102
 103     fChars = LE_NEW_ARRAY(LEUnicode, charCount + 1);
 104     LE_ARRAY_COPY(fChars, chars, charCount);
 105     fChars[charCount] = 0;
 106
 107     LEUnicode *pStart = &fChars[0];
 108
 109     while (*pStart != 0) {
 110         LEUnicode *pEnd = u_strpbrk(pStart, separators);
 111         le_int32 pAscent, pDescent, pLeading;
 112         ParagraphLayout *paragraphLayout = NULL;
 113
 114         if (pEnd == NULL) {
 115             pEnd = &fChars[charCount];
 116         }
 117
 118         if (pEnd != pStart) {
 119             subsetFontRuns(fontRuns, pStart - fChars, pEnd - fChars, &fr);
 120
 121             paragraphLayout = new ParagraphLayout(pStart, pEnd - pStart, &fr, NULL, NULL, locales, fParagraphLevel, FALSE, status);
 122
 123             if (LE_FAILURE(status)) {
 124                 delete paragraphLayout;
 125                 break; // return? something else?
 126             }
 127
 128             if (fParagraphLevel == UBIDI_DEFAULT_LTR) {
 129                 fParagraphLevel = paragraphLayout->getParagraphLevel();
 130             }
 131
 132             pAscent  = paragraphLayout->getAscent();
 133             pDescent = paragraphLayout->getDescent();
 134             pLeading = paragraphLayout->getLeading();
 135
 136             if (pAscent > ascent) {
 137                 ascent = pAscent;
 138             }
 139
 140             if (pDescent > descent) {
 141                 descent = pDescent;
 142             }
 143
 144             if (pLeading > leading) {
 145                 leading = pLeading;
 146             }
 147         }
 148
 149         if (fParagraphCount >= fParagraphMax) {
 150             fParagraphLayout = (ParagraphLayout **) LE_GROW_ARRAY(fParagraphLayout, fParagraphMax + fParagraphGrow);
 151             fParagraphMax += fParagraphGrow;
 152         }
 153
 154         fParagraphLayout[fParagraphCount++] = paragraphLayout;
 155
 156         if (*pEnd == 0) {
 157             break;
 158         }
 159
 160         pStart = skipLineEnd(pEnd);
 161     }
 162
 163     fLineHeight = ascent + descent + leading;
 164     fAscent     = ascent;
 165 }
 166
 167 Paragraph::~Paragraph()
 168 {
 169     for (le_int32 line = 0; line < fLineCount; line += 1) {
 170         delete /*(LineInfo *)*/ fLines[line];
 171     }
 172
 173     for (le_int32 paragraph = 0; paragraph < fParagraphCount; paragraph += 1) {
 174         delete fParagraphLayout[paragraph];
 175     }
 176
 177     LE_DELETE_ARRAY(fLines);
 178     LE_DELETE_ARRAY(fParagraphLayout);
 179     LE_DELETE_ARRAY(fChars);
 180 }
 181
 182 void Paragraph::addLine(const ParagraphLayout::Line *line)
 183 {
 184     if (fLineCount >= fLinesMax) {
 185         fLines = (const ParagraphLayout::Line **) LE_GROW_ARRAY(fLines, fLinesMax + fLinesGrow);
 186         fLinesMax += fLinesGrow;
 187     }
 188
 189     fLines[fLineCount++] = line;
 190 }
 191
 192 void Paragraph::breakLines(le_int32 width, le_int32 height)
 193 {
 194     fHeight = height;
 195
 196     // don't re-break if the width hasn't changed
 197     if (fWidth == width) {
 198         return;
 199     }
 200
 201     fWidth  = width;
 202
 203     float lineWidth = (float) (width - 2 * MARGIN);
 204     const ParagraphLayout::Line *line;
 205
 206     // Free the old LineInfo's...
 207     for (le_int32 li = 0; li < fLineCount; li += 1) {
 208         delete fLines[li];
 209     }
 210
 211     fLineCount = 0;
 212
 213     for (le_int32 p = 0; p < fParagraphCount; p += 1) {
 214         ParagraphLayout *paragraphLayout = fParagraphLayout[p];
 215
 216         if (paragraphLayout != NULL) {
 217             paragraphLayout->reflow();
 218             while ((line = paragraphLayout->nextLine(lineWidth)) != NULL) {
 219                 addLine(line);
 220             }
 221         } else {
 222             addLine(NULL);
 223         }
 224     }
 225 }
 226
 227 void Paragraph::draw(RenderingSurface *surface, le_int32 firstLine, le_int32 lastLine)
 228 {
 229     le_int32 li, x, y;
 230
 231     x = MARGIN;
 232     y = fAscent;
 233
 234     for (li = firstLine; li <= lastLine; li += 1) {
 235         const ParagraphLayout::Line *line = fLines[li];
 236
 237         if (line != NULL) {
 238             le_int32 runCount = line->countRuns();
 239             le_int32 run;
 240
 241                     if (fParagraphLevel == UBIDI_RTL) {
 242                             le_int32 lastX = line->getWidth();
 243
 244                             x = (fWidth - lastX - MARGIN);
 245                     }
 246
 247
 248             for (run = 0; run < runCount; run += 1) {
 249                 const ParagraphLayout::VisualRun *visualRun = line->getVisualRun(run);
 250                 le_int32 glyphCount = visualRun->getGlyphCount();
 251                 const LEFontInstance *font = visualRun->getFont();
 252                 const LEGlyphID *glyphs = visualRun->getGlyphs();
 253                 const float *positions = visualRun->getPositions();
 254
 255                 surface->drawGlyphs(font, glyphs, glyphCount, positions, x, y, fWidth, fHeight);
 256             }
 257         }
 258
 259         y += fLineHeight;
 260     }
 261 }
 262
 263 Paragraph *Paragraph::paragraphFactory(const char *fileName, const LEFontInstance *font, GUISupport *guiSupport)
 264 {
 265     LEErrorCode status  = LE_NO_ERROR;
 266     le_int32 charCount;
 267     const UChar *text = UnicodeReader::readFile(fileName, guiSupport, charCount);
 268     Paragraph *result = NULL;
 269
 270     if (text == NULL) {
 271         return NULL;
 272     }
 273
 274     FontRuns  fontRuns(0);
 275
 276     fontRuns.add(font, charCount);
 277
 278     result = new Paragraph(text, charCount, &fontRuns, status);
 279
 280         if (LE_FAILURE(status)) {
 281                 delete result;
 282                 result = NULL;
 283         }
 284
 285     LE_DELETE_ARRAY(text);
 286
 287     return result;
 288 }
 289