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gnu.java.awt.font.opentype

Class Scaler

Known Direct Subclasses:
TrueTypeScaler
public abstract class Scaler
extends Object
An common superclass for all font scalers. The main task of font scaler is to retrieve a scaled and hinted outline for a glyph.

To make text more legible, high-quality fonts contain instructions (sometimes also called “hints”) for moving the scaled control points towards the coordinate grid of the display device.

Lack of Thread Safety: Font scalers are intentionally not safe to access from multiple concurrent threads. Synchronization needs to be performed externally. Usually, the font that uses this scaler already has obtained a lock before calling the scaler.

Method Summary

abstract void
getAdvance(int glyphIndex, float pointSize, AffineTransform transform, boolean antialias, boolean fractionalMetrics, boolean horizontal, Point2D advance)
Determines the advance width and height for a glyph.
abstract float
getAscent(float pointSize, AffineTransform transform, boolean antialias, boolean fractionalMetrics, boolean horizontal)
Determines the distance between the base line and the highest ascender.
abstract float
getDescent(float pointSize, AffineTransform transform, boolean antialiased, boolean fractionalMetrics, boolean horizontal)
Determines the distance between the base line and the lowest descender.
abstract GeneralPath
getOutline(int glyph, float pointSize, AffineTransform transform, boolean antialias, boolean fractionalMetrics, Hinter hinter, int type)
Retrieves the scaled outline of a glyph, adjusting control points to the raster grid if necessary.
abstract Zone
getRawOutline(int glyph, AffineTransform transform)
Returns the raw outline data.

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

getAdvance

public abstract void getAdvance(int glyphIndex,
                                float pointSize,
                                AffineTransform transform,
                                boolean antialias,
                                boolean fractionalMetrics,
                                boolean horizontal,
                                Point2D advance)
Determines the advance width and height for a glyph.
Parameters:
glyphIndex - the glyph whose advance width is to be determined.
pointSize - the point size of the font.
transform - a transform that is applied in addition to scaling to the specified point size. This is often used for scaling according to the device resolution. Those who lack any aesthetic sense may also use the transform to slant or stretch glyphs.
antialias - true for anti-aliased rendering, false for normal rendering. For hinted fonts, this parameter may indeed affect the result.
fractionalMetrics - true for fractional metrics, false for rounding the result to a pixel boundary.
horizontal - true for horizontal line layout, false for vertical line layout.
advance - a point whose x and y fields will hold the advance in each direction. It is well possible that both values are non-zero, for example for rotated text or for Urdu fonts.

getAscent

public abstract float getAscent(float pointSize,
                                AffineTransform transform,
                                boolean antialias,
                                boolean fractionalMetrics,
                                boolean horizontal)
Determines the distance between the base line and the highest ascender.
Parameters:
pointSize - the point size of the font.
transform - a transform that is applied in addition to scaling to the specified point size. This is often used for scaling according to the device resolution. Those who lack any aesthetic sense may also use the transform to slant or stretch glyphs.
antialias - true for anti-aliased rendering, false for normal rendering. For hinted fonts, this parameter may indeed affect the result.
fractionalMetrics - true for fractional metrics, false for rounding the result to a pixel boundary.
horizontal - true for horizontal line layout, false for vertical line layout.
Returns:
the ascent, which usually is a positive number.

getDescent

public abstract float getDescent(float pointSize,
                                 AffineTransform transform,
                                 boolean antialiased,
                                 boolean fractionalMetrics,
                                 boolean horizontal)
Determines the distance between the base line and the lowest descender.
Parameters:
pointSize - the point size of the font.
transform - a transform that is applied in addition to scaling to the specified point size. This is often used for scaling according to the device resolution. Those who lack any aesthetic sense may also use the transform to slant or stretch glyphs.
antialiased - true for anti-aliased rendering, false for normal rendering. For hinted fonts, this parameter may indeed affect the result.
fractionalMetrics - true for fractional metrics, false for rounding the result to a pixel boundary.
horizontal - true for horizontal line layout, false for vertical line layout.
Returns:
the descent, which usually is a nagative number.

getOutline

public abstract GeneralPath getOutline(int glyph,
                                       float pointSize,
                                       AffineTransform transform,
                                       boolean antialias,
                                       boolean fractionalMetrics,
                                       Hinter hinter,
                                       int type)
Retrieves the scaled outline of a glyph, adjusting control points to the raster grid if necessary.
Parameters:
glyph - the glyph number whose outline is retrieved.
pointSize - the point size of the font.
transform - a transform that is applied in addition to scaling to the specified point size. This is often used for scaling according to the device resolution. Those who lack any aesthetic sense may also use the transform to slant or stretch glyphs.
antialias - whether or not the rasterizer will perform anti-aliasing on the returned path.
fractionalMetrics - false for adjusting glyph positions to the raster grid of device space.
Returns:
the scaled and grid-fitted outline of the specified glyph, or null for bitmap fonts.

getRawOutline

public abstract Zone getRawOutline(int glyph,
                                   AffineTransform transform)
Returns the raw outline data. This is used for the autofitter atm.
Parameters:
glyph - the glyph index
transform - the transform to apply
Returns:
the raw glyph outline
Scaler.java -- Common superclass for font scalers. Copyright (C) 2006 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath 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 for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.

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