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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.myfaces.trinidadinternal.image.painter;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.font.TextAttribute;
import java.awt.font.TextHitInfo;
import java.awt.font.TextLayout;
import java.text.AttributedString;
import org.apache.myfaces.trinidadinternal.util.nls.LocaleUtils;
/**
* A painter capable of painting a string using the alignment of its
* PaintContext. If the string contains newlines, multiple lines
* of text will be painted.
*
* This class uses new APIs in Java2 and propertly works with
* BufferedImages.
*
* This TextPainter should be used for all String objects used in the
* ImageGenerator.
*
* @version $Name: $ ($Revision: adfrt/faces/adf-faces-impl/src/main/java/oracle/adfinternal/view/faces/image/painter/TextPainter.java#1 $) $Date: 11-nov-2005.14:59:38 $
*/
public class TextPainter extends AbstractPainter
{
/**
* Creates a TextPainter object, using the default label data key.
* and supporting mnemonics.
*/
public TextPainter()
{
_init(PaintContext.LABEL_KEY, true);
}
/**
* Creates a TextPainter object using the dataKey to get its
* data and supporting mnemonics.
*
* @param dataKey Key used by this TextPainter to retrieve the String
* this TextPainter paints.
*
* @see PaintContext#getPaintData
*/
public TextPainter(
Object dataKey
)
{
_init(dataKey, true);
}
/**
* Creates a TextPainter object.
*
* @param dataKey Key used by this TextPainter to retrieve the
* String this TextPainter paints.
* @param supportMnemonics True if this TextPainter should ask its
* Paint context for a mnemonic to paint.
*
* @see PaintContext#getPaintData
*/
public TextPainter(
Object dataKey,
boolean supportMnemonics
)
{
_init(dataKey, supportMnemonics);
}
/**
* Returns the preferred size of the painter.
*
* @param context Context for determining the preferred size.
* @return The preferred size of the Painter.
*/
@Override
public Dimension getPreferredSize(
PaintContext context
)
{
return _getSize(context, true);
}
/**
* Returns the minimum size of the painter.
*
* @param context Context for determining the minimum size.
* @return The minimum size of the Painter.
*/
public Dimension getMinimumSize(
PaintContext context
)
{
return _getSize(context, false);
}
/**
* Paints the TextPainter at the given location.
*
* @param context Context for painting.
* @param g Graphics object to draw into.
* @param x X position to draw at.
* @param y Y position to draw at.
* @param width Width to draw into.
* @param height Height to draw into.
*/
public void paint(
PaintContext context,
Graphics g,
int x,
int y,
int width,
int height
)
{
// We synchronize on the _FONT_LOCK object so that we only
// render/measure one text String at a time.
// This oddness is due to bug 1852105 (ANTIALIASED TEXT MAY
// SOMETIMES APPEAR BOLD). The problem seems to be due to
// buggy behavior in how AWT maintains internal font state.
// After rendering/measuring with a bold antialiased font,
// subsequent rendering/measuring with the same font results
// in bold appearance/metrics, even if the style is set to
// Font.PLAIN. To avoid this, we serialize all text
// rendering/measuring, and explicitly force the font
// to be reset before doing any rendering/measuring.
// Note: This behavior has not yet been observed in JDK 1.4,
// so hopefully this hack can be removed before long.
synchronized (_FONT_LOCK)
{
// Reset the font state before we do anything.
_resetFont(g);
// Now it should be safe to get/use the FontMetrics,
// as well as to paint the text.
FontMetrics metrics = g.getFontMetrics();
if (metrics != null)
{
String text = getStringData(context);
if (text != null)
{
int textLength = text.length();
if (textLength != 0)
{
float alignmentX = context.getInteriorAlignmentX();
int numLines = _getNumberOfTextLines(text);
//
// adjust Y for vertical alignment
//
float alignmentY = context.getInteriorAlignmentY();
if (alignmentY != Component.TOP_ALIGNMENT)
{
int stringHeight = numLines * metrics.getHeight();
if (stringHeight < height)
{
y += (height - stringHeight) * alignmentY;
}
}
// adjust y for baseline of text
y += metrics.getAscent();
//
// get the mnemonic, if any
//
int mnemonicIndex = -1;
if (_supportMnemonics)
{
Object mnemonic =
context.getPaintData(PaintContext.MNEMONIC_INDEX_KEY);
if ((mnemonic != null) && (mnemonic instanceof Integer))
{
mnemonicIndex = ((Integer)mnemonic).intValue();
}
}
//
// Draw each line of text. We treat single line of text that
// end in a carraige return as multiple lines of text to make
// sure that we don't pass a carraige return at the end of
// a single line of text to paintText()
//
if ((numLines == 1) && (text.charAt(textLength - 1) != '\n'))
{
// all text on the same line
paintText(context,
g,
metrics,
text,
x,
y,
width,
alignmentX,
mnemonicIndex);
}
else
{
int lastIndex;
int currIndex = -1;
int lineHeight = metrics.getHeight();
do
{
lastIndex = currIndex + 1;
if (lastIndex >= textLength)
break;
currIndex = text.indexOf('\n', lastIndex);
if (currIndex == -1)
{
currIndex = textLength;
}
paintText(context,
g,
metrics,
text.substring(lastIndex, currIndex),
x,
y,
width,
alignmentX,
mnemonicIndex - lastIndex);
// move down to next line
y += lineHeight;
} while (true);
}
}
}
}
}
}
/**
* This method is called for each line of text painted. Given a line of text,
* return the line of text to actually draw. Subclasses, that wish to modify
* the text displayed should override this method.
*
* @param context Context for determining the text to paint.
* @param text Text data for this line.
* @param metrics FontMetrics to use to paint the text.
* @param availableWidth Number of pixels available to paint the text.
*
* @return The String to actually paint.
*/
protected String getPaintText(
PaintContext context,
String text,
FontMetrics metrics,
int availableWidth
)
{
return text;
}
/**
* Typesafe method to return the String to Paint.
* Subclasses that do not use data keys to retrieve
* their data should override this method, rather than
* getData(), as overriding getStringData()
* directly is more efficient.
*
* @param context PaintContext to use to retrieve the TextPainter's
* String data.
*
* @return The String to paint.
*
* @see #getData
*/
protected String getStringData(
PaintContext context
)
{
return (String)getData(context);
}
/**
* Returns the String to use for the minimum size calculation. This allows
* subclasses to create TextPainters that use different strings for
* calculating their minimum sizes than they do for actually displaying
* the current value. The default implementation is to use the current
* value.
*/
protected String getMinimumStringData(
PaintContext context
)
{
return getStringData(context);
}
@Override
protected Object getData(
PaintContext context
)
{
Object data = super.getData(context);
if (data != null)
{
return data.toString();
}
else
{
return null;
}
}
@Override
protected Object getDataKey()
{
return _dataKey;
}
private Dimension _getSize(
PaintContext context,
boolean usePreferredSize
)
{
int width = 0;
int height = 0;
Font font = context.getPaintFont();
Graphics g = context.getPaintGraphics();
if (font != null)
{
String text = (usePreferredSize
? getStringData(context)
: getMinimumStringData(context));
// Due to bug 1852105 (ANTIALIASED TEXT MAY SOMETIMES APPEAR BOLD),
// we synchronize on the _FONT_LOCK object to serialize all text
// rendering/measuring. See comment in paint() method above for
// more details.
synchronized (_FONT_LOCK)
{
// Reset the font state before we do anything.
_resetFont(g);
// Now it should be safe to get/use the FontMetrics
FontMetrics metrics = context.getFontMetrics(font);
if ((metrics != null) && (text != null))
{
int numLines = _getNumberOfTextLines(text);
if (numLines == 1)
{
text = StringUtils.getDisplayString(text, context);
// get the string width
width = _getStringWidth(text, metrics, g);
}
else
{
width = _getMaxLineWidth(context, text, metrics, g);
}
height = (numLines * metrics.getHeight()) - metrics.getLeading();
}
}
}
return new Dimension(width, height);
}
/**
* Computer the number of lines of text that the passed in text contains
*/
private static final int _getNumberOfTextLines(
String text
)
{
int numLines = 0;
int currIndex;
int foundIndex = -1;
int textLength = text.length();
do
{
currIndex = foundIndex + 1;
if (currIndex == textLength)
break;
foundIndex = text.indexOf('\n', currIndex);
numLines++;
} while (foundIndex != -1);
return numLines;
}
private static final int _getStringWidth(
String text,
FontMetrics metrics,
Graphics g
)
{
// =-=AEW Techically, this isn't correct. We really should
// be using AttributedString and TextLayout after setting up
// the reading direction. However, as long as we're only
// ever getting the width of the _entire_ string, we should be OK.
return (int)metrics.getStringBounds(text, g).getWidth();
}
private static final int _getMaxLineWidth(
PaintContext context,
String text,
FontMetrics metrics,
Graphics g
)
{
int maxWidth = 0;
int lastIndex;
int currIndex = -1;
int textLength = text.length();
do
{
lastIndex = currIndex + 1;
if (lastIndex >= textLength)
break;
currIndex = text.indexOf('\n', lastIndex);
if (currIndex == -1)
currIndex = textLength;
String subtext = StringUtils.getDisplayString(
text.substring(lastIndex, currIndex),
context);
// get the width of the string
int currWidth = _getStringWidth(subtext, metrics, g);
if (maxWidth < currWidth)
maxWidth = currWidth;
} while (true);
return maxWidth;
}
protected int paintText(
PaintContext context,
Graphics g,
FontMetrics metrics,
String text,
int x,
int y,
int availableWidth,
float alignmentX,
int mnemonicIndex
)
{
// Convert the text to bidi
text = StringUtils.getDisplayString(text, context);
// get the text to paint
String paintText = getPaintText(context, text, metrics, availableWidth);
if (alignmentX != Component.LEFT_ALIGNMENT)
{
int stringWidth = _getStringWidth(paintText, metrics, g);
if (stringWidth < availableWidth)
{
x += (availableWidth - stringWidth) * alignmentX;
}
}
// paint the text. Before drawing the text, make sure
// we clue the system in on the default direction of the run -
// we do _not_ want to use the direction of the first character
// in this text.
Graphics2D g2 = (Graphics2D) g;
AttributedString as = new AttributedString(paintText);
as.addAttribute(TextAttribute.FONT, g2.getFont());
Object direction;
if (context.getReadingDirection() == LocaleUtils.DIRECTION_LEFTTORIGHT)
direction = TextAttribute.RUN_DIRECTION_LTR;
else
direction = TextAttribute.RUN_DIRECTION_RTL;
as.addAttribute(TextAttribute.RUN_DIRECTION, direction);
g2.drawString(as.getIterator(), x, y);
//
// paint the mnemonic if necessary
//
if ((mnemonicIndex >= 0) && (mnemonicIndex < paintText.length()))
{
TextLayout layout = new TextLayout(as.getIterator(),
g2.getFontRenderContext());
TextHitInfo leading = TextHitInfo.leading(mnemonicIndex);
TextHitInfo trailing = TextHitInfo.trailing(mnemonicIndex);
Rectangle r =
layout.getVisualHighlightShape(leading, trailing).getBounds();
// draw a horizontal line under the specified character to indicate
// that it is the mnemonic.
int left = r.x + x;
g.drawLine(left + 1,
y + 1,
left + r.width - 1,
y + 1);
}
return x;
}
private void _init(
Object dataKey,
boolean supportMnemonics
)
{
_dataKey = dataKey;
_supportMnemonics = supportMnemonics;
}
// This method is needed to work around
// bug 1852105 (ANTIALIASED TEXT MAY SOMETIMES APPEAR BOLD).
// To get AWT to pick up the right Font/FontMetrics, we
// first reset the font on the Graphics object to a 1pt
// version of the current font, and then get the font
// metrics. Then, we reset the Graphics object to use the
// actual font that we want, at which point subsequent calls
// to Graphics.getFontMetrics()/paintText() work correctly.
private static void _resetFont(Graphics g)
{
Font font = g.getFont();
// We set the font to be the same font family/style as
// the current font, but a different size (1pt).
g.setFont(new Font(font.getName(), font.getStyle(), 1));
// Then, get the font metrics, this seems to reset the
// graphics state.
g.getFontMetrics();
// Finally, reset the original font. Now, if we get the
// font metrics again or paint some text, the right font/
// font metrics will be used.
g.setFont(font);
}
private boolean _supportMnemonics;
private Object _dataKey;
// This lock is used to serialize all text rendering/measuring,
// which is done to work around bug 1852105 (ANTIALIASED TEXT
// MAY SOMETIMES APPEAR BOLD).
private static final Object _FONT_LOCK = new Object();
}