| /* |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| /* |
| * |
| * (C) Copyright IBM Corp. 2003 - All Rights Reserved |
| */ |
| |
| package sun.font; |
| |
| /** |
| * Iterates over runs of fonts in a CompositeFont, optionally taking script runs into account. |
| */ |
| public final class FontRunIterator { |
| CompositeFont font; |
| char[] text; |
| int start; |
| int limit; |
| |
| CompositeGlyphMapper mapper; // handy cache |
| |
| int slot = -1; |
| int pos; |
| |
| public void init(CompositeFont font, char[] text, int start, int limit) { |
| if (font == null || text == null || start < 0 || limit < start || limit > text.length) { |
| throw new IllegalArgumentException(); |
| } |
| |
| this.font = font; |
| this.text = text; |
| this.start = start; |
| this.limit = limit; |
| |
| this.mapper = (CompositeGlyphMapper)font.getMapper(); |
| this.slot = -1; |
| this.pos = start; |
| } |
| |
| public PhysicalFont getFont() { |
| return slot == -1 ? null : font.getSlotFont(slot); |
| } |
| |
| public int getGlyphMask() { |
| return slot << 24; |
| } |
| |
| public int getPos() { |
| return pos; |
| } |
| |
| /* |
| * characters that are in the 'common' script become part of the |
| * surrounding script run. we want to fetch these from the same font |
| * used to get surrounding characters, where possible. but we don't |
| * want to force non-common characters to come from other than their |
| * standard font. |
| * |
| * what we really want to do is this: |
| * 1) fetch a code point from the text. |
| * 2) get its 'native' script code |
| * 3) determine its 'resolved' script code |
| * 4) if its native script is COMMON, and its resolved script is the same as the previous |
| * code point's, then see if the previous font supports this code point. if so, use it. |
| * 5) otherwise resolve the font as usual |
| * 6) break the run when either the physical font or the resolved script changes. |
| * |
| * problems: we optimize latin-1 and cjk text assuming a fixed |
| * width for each character. since latin-1 digits and punctuation |
| * are common, following this algorithm they will change to match |
| * the fonts used for the preceding text, and potentially change metrics. |
| * |
| * this also seems to have the potential for changing arbitrary runs of text, e.g. |
| * any number of digits and spaces can change depending on the preceding (or following!) |
| * non-COMMON character's font assignment. this is not good. |
| * |
| * since the goal is to enable layout to be performed using as few physical fonts as |
| * possible, and the primary cause of switching fonts is to handle spaces, perhaps |
| * we should just special-case spaces and assign them from the current font, whatever |
| * it may be. |
| * |
| * One could also argue that the job of the composite font is to assign physical fonts |
| * to text runs, however it wishes. we don't necessarily have to provide script info |
| * to let it do this. it can determine based on whatever. so having a special 'next' |
| * function that takes script (and limit) is redundant. It can fetch the script again |
| * if need be. |
| * |
| * both this and the script iterator are turning char sequences into code point |
| * sequences. maybe it would be better to feed a single code point into each iterator-- push |
| * the data instead of pull it? |
| */ |
| |
| public boolean next(int script, int lim) { |
| if (pos == lim) { |
| return false; |
| } |
| |
| int ch = nextCodePoint(lim); |
| int sl = mapper.charToGlyph(ch) & CompositeGlyphMapper.SLOTMASK; |
| slot = sl >>> 24; |
| while ((ch = nextCodePoint(lim)) != DONE && (mapper.charToGlyph(ch) & CompositeGlyphMapper.SLOTMASK) == sl); |
| pushback(ch); |
| |
| return true; |
| } |
| |
| public boolean next() { |
| return next(Script.COMMON, limit); |
| } |
| |
| static final int SURROGATE_START = 0x10000; |
| static final int LEAD_START = 0xd800; |
| static final int LEAD_LIMIT = 0xdc00; |
| static final int TAIL_START = 0xdc00; |
| static final int TAIL_LIMIT = 0xe000; |
| static final int LEAD_SURROGATE_SHIFT = 10; |
| static final int SURROGATE_OFFSET = SURROGATE_START - (LEAD_START << LEAD_SURROGATE_SHIFT) - TAIL_START; |
| |
| static final int DONE = -1; |
| |
| int nextCodePoint() { |
| return nextCodePoint(limit); |
| } |
| |
| int nextCodePoint(int lim) { |
| if (pos >= lim) { |
| return DONE; |
| } |
| int ch = text[pos++]; |
| if (ch >= LEAD_START && ch < LEAD_LIMIT && pos < lim) { |
| int nch = text[pos]; |
| if (nch >= TAIL_START && nch < TAIL_LIMIT) { |
| ++pos; |
| ch = (ch << LEAD_SURROGATE_SHIFT) + nch + SURROGATE_OFFSET; |
| } |
| } |
| return ch; |
| } |
| |
| void pushback(int ch) { |
| if (ch >= 0) { |
| if (ch >= 0x10000) { |
| pos -= 2; |
| } else { |
| pos -= 1; |
| } |
| } |
| } |
| } |