/* 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
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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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
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permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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package gnu.java.awt.font.opentype;
import gnu.java.awt.font.opentype.truetype.Zone;
import java.awt.geom.AffineTransform;
import java.awt.geom.GeneralPath;
import java.awt.geom.Point2D;
/**
* An common superclass for all font scalers. The main task of font
* scaler is to retrieve a scaled and hinted outline for a glyph.
*
* <p>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.
*
* <p><b>Lack of Thread Safety:</b> Font scalers are intentionally
* <i>not</i> 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.
*
* @author Sascha Brawer (brawer@dandelis.ch)
*/
public abstract class Scaler
{
/**
* Retrieves the scaled outline of a glyph, adjusting control points
* to the raster grid if necessary.
*
* @param glyph the glyph number whose outline is retrieved.
*
* @param pointSize the point size of the font.
*
* @param 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.
*
* @param antialias whether or not the rasterizer will perform
* anti-aliasing on the returned path.
*
* @param fractionalMetrics <code>false</code> for adjusting glyph
* positions to the raster grid of device space.
*
* @return the scaled and grid-fitted outline of the specified
* glyph, or <code>null</code> for bitmap fonts.
*/
public abstract GeneralPath getOutline(int glyph,
float pointSize,
AffineTransform transform,
boolean antialias,
boolean fractionalMetrics,
Hinter hinter, int type);
/**
* Determines the advance width and height for a glyph.
*
* @param glyphIndex the glyph whose advance width is to be
* determined.
*
* @param pointSize the point size of the font.
*
* @param 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.
*
* @param antialias <code>true</code> for anti-aliased rendering,
* <code>false</code> for normal rendering. For hinted fonts,
* this parameter may indeed affect the result.
*
* @param fractionalMetrics <code>true</code> for fractional metrics,
* <code>false</code> for rounding the result to a pixel boundary.
*
* @param horizontal <code>true</code> for horizontal line layout,
* <code>false</code> for vertical line layout.
*
* @param advance a point whose <code>x</code> and <code>y</code>
* 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.
*/
public abstract void getAdvance(int glyphIndex,
float pointSize,
AffineTransform transform,
boolean antialias,
boolean fractionalMetrics,
boolean horizontal,
Point2D advance);
/**
* Determines the distance between the base line and the highest
* ascender.
*
* @param pointSize the point size of the font.
*
* @param 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.
*
* @param antialias <code>true</code> for anti-aliased rendering,
* <code>false</code> for normal rendering. For hinted fonts,
* this parameter may indeed affect the result.
*
* @param fractionalMetrics <code>true</code> for fractional metrics,
* <code>false</code> for rounding the result to a pixel boundary.
*
* @param horizontal <code>true</code> for horizontal line layout,
* <code>false</code> for vertical line layout.
*
* @return the ascent, which usually is a positive number.
*/
public abstract float getAscent(float pointSize,
AffineTransform transform,
boolean antialias,
boolean fractionalMetrics,
boolean horizontal);
/**
* Determines the distance between the base line and the lowest
* descender.
*
* @param pointSize the point size of the font.
*
* @param 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.
*
* @param antialiased <code>true</code> for anti-aliased rendering,
* <code>false</code> for normal rendering. For hinted fonts,
* this parameter may indeed affect the result.
*
* @param fractionalMetrics <code>true</code> for fractional metrics,
* <code>false</code> for rounding the result to a pixel boundary.
*
* @param horizontal <code>true</code> for horizontal line layout,
* <code>false</code> for vertical line layout.
*
* @return the descent, which usually is a nagative number.
*/
public abstract float getDescent(float pointSize,
AffineTransform transform,
boolean antialiased,
boolean fractionalMetrics,
boolean horizontal);
/**
* Returns the raw outline data. This is used for the autofitter atm.
*
* @param glyph the glyph index
* @param transform the transform to apply
*
* @return the raw glyph outline
*/
public abstract Zone getRawOutline(int glyph, AffineTransform transform);
}