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jeremybenn |
/* TrueTypeScaler.java -- Font scaler for TrueType outlines.
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Copyright (C) 2006 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package gnu.java.awt.font.opentype.truetype;
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import gnu.java.awt.font.opentype.Hinter;
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import gnu.java.awt.font.opentype.Scaler;
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import java.awt.FontFormatException;
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import java.awt.geom.AffineTransform;
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import java.awt.geom.GeneralPath;
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import java.awt.geom.Point2D;
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import java.nio.ByteBuffer;
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/**
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* A scaler for fonts whose outlines are described in the TrueType
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* format.
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*
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* <p><b>Lack of Thread Safety:</b> Font scalers are intentionally
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* <i>not</i> safe to access from multiple concurrent threads.
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* Synchronization needs to be performed externally. Usually, the font
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* that uses this scaler already has obtained a lock before calling
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* the scaler.
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*
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* @author Sascha Brawer (brawer@dandelis.ch)
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*/
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public final class TrueTypeScaler
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extends Scaler
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{
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/**
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* The TrueType or OpenType table that contains the glyph outlines.
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*/
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private ByteBuffer glyfTable;
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/**
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* A helper object for loading glyph outlines.
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*/
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private GlyphLoader glyphLoader;
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/**
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* A helper object for measuring the advance width and height of a
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* glyph.
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*/
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private final GlyphMeasurer glyphMeasurer;
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private final Zone glyphZone;
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/**
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* The number of units per em. A typical value is 2048, but some
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* font use other numbers as well.
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*/
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private int unitsPerEm;
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/**
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* Constructs a new TrueTypeScaler.
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*
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* @param unitsPerEm the number of font units per em. This value can
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* be retrieved from the font’s <code>head</code> table.
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*
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* @param maxp the <code>maxp</code> table of the font, which
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* contains various constants needed for setting up the virtual
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* machine that interprets TrueType bytecodes.
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*
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* @param controlValueTable the <code>cvt</code> table of the font,
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* which contains the initial values of the control value table.
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*
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* @param fpgm the <code>fpgm</code> table of the font, which
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* contains a font program that is executed exactly once. The
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* purpose of the font program is to define functions and to patch
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* the interpreter.
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*
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* @param locaFormat the format of the <code>loca</code> table. The
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* value must be 0 for two-byte offsets, or 1 for four-byte
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* offsets. TrueType and OpenType fonts indicate the format in the
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* <code>indexToLoc</code> field of the <a href=
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* "http://partners.adobe.com/asn/tech/type/opentype/head.html"
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* >font header</a>.
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*
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* @param loca the <code>loca</code> table of the font, which
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* contains for each glyph the offset of its outline data
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* in <code>glyf</code>.
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*
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* @param glyf the <code>glyf</code> table of the font, which
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* contains the outline data for all glyphs in the font.
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*
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* @param preProgram the <code>prep</code> table of the font, which
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* contains a program that is executed whenever the point size or
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* the device transform have changed. This program is called
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* pre-program because it gets executed before the instructions of
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* the individual glyphs. If the font does not contain a
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* pre-program, pass <code>null</code>.
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*
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* @throws FontFormatException if <code>format</code> is neither 0
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* nor 1.
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*/
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public TrueTypeScaler(int unitsPerEm,
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ByteBuffer hhea,
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ByteBuffer htmx,
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ByteBuffer vhea,
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ByteBuffer vtmx,
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ByteBuffer maxp,
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ByteBuffer controlValueTable,
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ByteBuffer fpgm,
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int locaFormat, ByteBuffer loca,
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ByteBuffer glyf,
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ByteBuffer preProgram)
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throws FontFormatException
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{
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int maxContours, maxPoints;
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VirtualMachine vm;
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maxContours = Math.max(/* maxContours */ (int) maxp.getChar(8),
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/* maxCompositeContours */ (int) maxp.getChar(12))
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+ /* fix for some broken fonts */ 8;
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maxPoints = Math.max(/* maxPoints */ (int) maxp.getChar(6),
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/* maxCompositePoints */ (int) maxp.getChar(10))
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+ /* fix for some broken fonts */ 12;
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glyphZone = new Zone(maxPoints + /* four phantom points */ 4);
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this.glyfTable = glyf;
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vm = new VirtualMachine(unitsPerEm, maxp,
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controlValueTable, fpgm,
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preProgram);
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GlyphLocator locator = GlyphLocator.forTable(locaFormat, loca, glyf);
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glyphMeasurer = new GlyphMeasurer(hhea, htmx, vhea, vtmx);
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glyphLoader = new GlyphLoader(locator, vm, unitsPerEm,
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maxContours, maxPoints,
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glyphMeasurer);
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this.unitsPerEm = unitsPerEm;
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}
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/**
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* Retrieves the scaled outline of a glyph, adjusting control points
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* to the raster grid if necessary.
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*
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* @param glyphIndex the glyph number whose outline is retrieved.
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*
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* @param pointSize the point size for the glyph.
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*
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* @param deviceTransform an affine transformation for the device.
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*
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* @param antialias whether or not the rasterizer will perform
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* anti-aliasing on the returned path.
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*
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* @param fractionalMetrics <code>false</code> for adjusting glyph
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* positions to the raster grid of device space.
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*/
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public GeneralPath getOutline(int glyphIndex,
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float pointSize,
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AffineTransform deviceTransform,
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boolean antialias,
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boolean fractionalMetrics, Hinter hinter,
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int type)
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{
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glyphLoader.loadGlyph(glyphIndex, pointSize, deviceTransform,
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antialias, glyphZone, hinter);
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return glyphZone.getPath(type);
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}
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public Zone getRawOutline(int glyphIndex, AffineTransform transform)
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{
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Zone zone = new Zone(glyphZone.getCapacity());
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glyphLoader.loadGlyph(glyphIndex, transform, zone, null);
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return zone;
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}
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/**
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* Determines the advance width and height for a glyph.
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*
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* @param glyphIndex the glyph whose advance width and height is to
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* be determined.
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*
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* @param pointSize the point size of the font.
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*
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* @param transform a transform that is applied in addition to
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* scaling to the specified point size. This is often used for
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* scaling according to the device resolution. Those who lack any
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* aesthetic sense may also use the transform to slant or stretch
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* glyphs.
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*
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* @param antialias <code>true</code> for anti-aliased rendering,
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* <code>false</code> for normal rendering. For hinted fonts,
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* this parameter may indeed affect the result.
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*
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* @param fractionalMetrics <code>true</code> for fractional metrics,
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* <code>false</code> for rounding the result to a pixel boundary.
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*
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* @param horizontal <code>true</code> for horizontal line layout,
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* <code>false</code> for vertical line layout.
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*
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* @param advance a point whose <code>x</code> and <code>y</code>
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* fields will hold the advance in each direction. It is possible
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* that both values are non-zero, for example if
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* <code>transform</code> is a rotation, or in the case of Urdu
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* fonts.
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*/
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public void getAdvance(int glyphIndex,
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float pointSize,
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AffineTransform transform,
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boolean antialias,
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boolean fractionalMetrics,
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boolean horizontal,
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Point2D advance)
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{
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double x, y;
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double scaleFactor = (double) pointSize / unitsPerEm;
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/* FIXME: Should grid-fit if needed. Also, use cache if present
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* in the font.
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*/
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advance.setLocation(
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scaleFactor * glyphMeasurer.getAdvanceWidth(glyphIndex, horizontal),
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scaleFactor * glyphMeasurer.getAdvanceHeight(glyphIndex, horizontal));
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transform.transform(advance, advance);
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}
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/**
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* Scales a value from font units to pixels, given the point size
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* and the transform.
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*
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* @param pointSize the point size of the font.
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*
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* @param transform a transform that is applied in addition to
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* scaling to the specified point size. This is often used for
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* scaling according to the device resolution.
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*
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* @param fractionalMetrics <code>true</code> for fractional
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* metrics, <code>false</code> for rounding the result to a pixel
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* boundary.
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*
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* @param horizontal <code>true</code> if the <code>funits</code>
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* value is along the x axis, <code>false</code> if it is along the
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* y axis.
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*/
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private float scaleFromFUnits(int funits,
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float pointSize,
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AffineTransform transform,
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boolean fractionalMetrics,
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boolean horizontal)
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{
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double s;
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s = (double) pointSize / unitsPerEm;
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if (transform != null)
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s *= horizontal ? transform.getScaleY() : transform.getScaleX();
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s *= funits;
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if (!fractionalMetrics)
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s = Math.round(s);
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return (float) s;
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}
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/**
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* Determines the distance between the base line and the highest
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* ascender.
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*
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* @param pointSize the point size of the font.
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*
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* @param transform a transform that is applied in addition to
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* scaling to the specified point size. This is often used for
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* scaling according to the device resolution. Those who lack any
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* aesthetic sense may also use the transform to slant or stretch
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* glyphs.
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*
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* @param antialias <code>true</code> for anti-aliased rendering,
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* <code>false</code> for normal rendering. For hinted fonts,
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* this parameter may indeed affect the result.
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*
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* @param fractionalMetrics <code>true</code> for fractional metrics,
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* <code>false</code> for rounding the result to a pixel boundary.
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*
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* @param horizontal <code>true</code> for horizontal line layout,
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* <code>false</code> for vertical line layout.
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*
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* @return the ascent, which usually is a positive number.
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*/
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public float getAscent(float pointSize,
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AffineTransform transform,
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boolean antialias,
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boolean fractionalMetrics,
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boolean horizontal)
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{
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/* Note that the ascent is orthogonal to the direction of line
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* layout: If the line direction is horizontal, the measurement of
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* ascent is along the vertical axis, and vice versa.
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*/
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return scaleFromFUnits(glyphMeasurer.getAscent(horizontal),
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pointSize,
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transform,
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fractionalMetrics,
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/* reverse */ !horizontal);
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}
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/**
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* Determines the distance between the base line and the lowest
|
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* descender.
|
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*
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* @param pointSize the point size of the font.
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*
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|
* @param transform a transform that is applied in addition to
|
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|
* scaling to the specified point size. This is often used for
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348 |
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|
* scaling according to the device resolution. Those who lack any
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349 |
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|
* aesthetic sense may also use the transform to slant or stretch
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* glyphs.
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*
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|
* @param antialiased <code>true</code> for anti-aliased rendering,
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* <code>false</code> for normal rendering. For hinted fonts,
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* this parameter may indeed affect the result.
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*
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* @param fractionalMetrics <code>true</code> for fractional metrics,
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* <code>false</code> for rounding the result to a pixel boundary.
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*
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* @param horizontal <code>true</code> for horizontal line layout,
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|
|
* <code>false</code> for vertical line layout.
|
361 |
|
|
*
|
362 |
|
|
* @return the descent, which usually is a nagative number.
|
363 |
|
|
*/
|
364 |
|
|
public float getDescent(float pointSize,
|
365 |
|
|
AffineTransform transform,
|
366 |
|
|
boolean antialiased,
|
367 |
|
|
boolean fractionalMetrics,
|
368 |
|
|
boolean horizontal)
|
369 |
|
|
{
|
370 |
|
|
/* Note that the descent is orthogonal to the direction of line
|
371 |
|
|
* layout: If the line direction is horizontal, the measurement of
|
372 |
|
|
* descent is along the vertical axis, and vice versa.
|
373 |
|
|
*/
|
374 |
|
|
return scaleFromFUnits(glyphMeasurer.getDescent(horizontal),
|
375 |
|
|
pointSize,
|
376 |
|
|
transform,
|
377 |
|
|
fractionalMetrics,
|
378 |
|
|
/* reverse */ !horizontal);
|
379 |
|
|
}
|
380 |
|
|
}
|