--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.desktop/share/classes/sun/font/FontRunIterator.java Sun Aug 17 15:54:13 2014 +0100
@@ -0,0 +1,171 @@
+/*
+ * 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;
+
+ final int nextCodePoint() {
+ return nextCodePoint(limit);
+ }
+
+ final 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;
+ }
+
+ final void pushback(int ch) {
+ if (ch >= 0) {
+ if (ch >= 0x10000) {
+ pos -= 2;
+ } else {
+ pos -= 1;
+ }
+ }
+ }
+}