/*
* 10/28/2004
*
* VisibleWhitespaceToken.java - Token that paints special symbols for its
* whitespace characters (space and tab).
*
* This library is distributed under a modified BSD license. See the included
* RSyntaxTextArea.License.txt file for details.
*/
package org.fife.ui.rsyntaxtextarea;
import java.awt.Color;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.geom.Rectangle2D;
import javax.swing.text.Segment;
import javax.swing.text.TabExpander;
/**
* This token class paints spaces and tabs with special symbols so the user
* can see the whitespace in his document. Rendering hints are honored.<p>
*
* The current implementation paints as follows:
* <ul>
* <li>The first tab or space, if any, is found in the token.</li>
* <li>If a tab was found, all characters up to it are painted as a
* group.</li>
* <li>If a space was found, all characters up to and including it are
* painted (it is painted with a special symbol to denote it as
* a space).</li>
* <li>If neither a tab nor a whitespace was found, all characters in the
* token are painted.</li>
* <li>Repeat until all characters are painted.</li>
* </ul>
* This means that rendering hints are applied to all groups of characters
* within a token, excluding whitespace and tabs.<p>
*
* A problem with this implementation is that FontMetrics.charsWidth() is still
* used to calculate the width of a group of chars painted. Thus, the group of
* characters will be painted with the rendering hints specified, but the
* following tab (or group of characters if the current group was the end of a
* token) will not necessarily be painted at the proper x-coordinate (as
* FontMetrics.charsWidth() returns an <code>int</code> and not a
* <code>float</code>). The way around this would be to calculate the token's
* width in such a way that a float is returned (Font.getStringBounds()?).
*
* @author Robert Futrell
* @version 0.5
* @see Token
* @see DefaultToken
*/
public class VisibleWhitespaceToken extends DefaultToken {
private Rectangle2D.Float dotRect;
/**
* Creates a "null token." The token itself is not null; rather, it
* signifies that it is the last token in a linked list of tokens and
* that it is not part of a "multi-line token."
*/
public VisibleWhitespaceToken() {
super();
dotRect = new Rectangle2D.Float(0,0, 1,1);
}
/**
* Constructor.
*
* @param line The segment from which to get the token.
* @param beg The first character's position in <code>line</code>.
* @param end The last character's position in <code>line</code>.
* @param startOffset The offset into the document at which this
* token begins.
* @param type A token type listed as "generic" above.
*/
public VisibleWhitespaceToken(final Segment line, final int beg,
final int end, final int startOffset, final int type) {
this(line.array, beg,end, startOffset, type);
}
/**
* Constructor.
*
* @param line The segment from which to get the token.
* @param beg The first character's position in <code>line</code>.
* @param end The last character's position in <code>line</code>.
* @param startOffset The offset into the document at which this
* token begins.
* @param type A token type listed as "generic" above.
*/
public VisibleWhitespaceToken(final char[] line, final int beg,
final int end, final int startOffset, final int type) {
super(line, beg,end, startOffset, type);
}
/**
* Paints this token, using special symbols for whitespace characters.
*
* @param g The graphics context in which to paint.
* @param x The x-coordinate at which to paint.
* @param y The y-coordinate at which to paint.
* @param host The text area this token is in.
* @param e How to expand tabs.
* @param clipStart The left boundary of the clip rectangle in which we're
* painting. This optimizes painting by allowing us to not paint
* not paint when this token is "to the left" of the clip rectangle.
* @return The x-coordinate representing the end of the painted text.
*/
public final float paint(Graphics2D g, float x, float y,
RSyntaxTextArea host, TabExpander e,
float clipStart) {
int origX = (int)x;
int end = textOffset + textCount;
float nextX = x;
int flushLen = 0;
int flushIndex = textOffset;
Color fg = host.getForegroundForToken(this);
Color bg = host.getBackgroundForToken(this);
g.setFont(host.getFontForTokenType(type));
FontMetrics fm = host.getFontMetricsForTokenType(type);
int ascent = fm.getAscent();
int height = fm.getHeight();
for (int i=textOffset; i<end; i++) {
switch (text[i]) {
case '\t':
// Fill in background.
nextX = x+fm.charsWidth(text, flushIndex,flushLen);
float nextNextX = e.nextTabStop(nextX, 0);
if (bg!=null) {
paintBackground(x,y, nextNextX-x,height, g,
ascent, host, bg);
}
g.setColor(fg);
// Paint chars cached before the tab.
if (flushLen > 0) {
g.drawChars(text, flushIndex, flushLen, (int)x,(int)y);
flushLen = 0;
}
flushIndex = i + 1;
// Draw an arrow representing the tab.
int halfHeight = height / 2;
int quarterHeight = halfHeight / 2;
int ymid = (int)y - ascent + halfHeight;
g.drawLine((int)nextX,ymid, (int)nextNextX,ymid);
g.drawLine((int)nextNextX,ymid, (int)nextNextX-4,ymid-quarterHeight);
g.drawLine((int)nextNextX,ymid, (int)nextNextX-4,ymid+quarterHeight);
x = nextNextX;
break;
case ' ':
// NOTE: There is a little bit of a "fudge factor"
// here when "smooth text" is enabled, as "width"
// below may well not be the width given to the space
// by fm.charsWidth() (it depends on how it places the
// space with respect to the preceding character).
// But, we assume the approximation is close enough for
// our drawing a dot for the space.
// "flushLen+1" ensures text is aligned correctly (or,
// aligned the same as in getWidth()).
nextX = x+fm.charsWidth(text, flushIndex,flushLen+1);
int width = fm.charWidth(' ');
// Paint background.
if (bg!=null) {
paintBackground(x,y, nextX-x,height, g,
ascent, host, bg);
}
g.setColor(fg);
// Paint chars before space.
if (flushLen>0) {
g.drawChars(text, flushIndex, flushLen, (int)x,(int)y);
flushLen = 0;
}
// Paint a dot representing the space.
dotRect.x = nextX - width/2.0f; // "2.0f" for FindBugs
dotRect.y = y - ascent + height/2.0f; // Ditto
g.fill(dotRect);
flushIndex = i + 1;
x = nextX;
break;
case '\f':
// ???
// fall-through for now.
default:
flushLen += 1;
break;
}
}
nextX = x+fm.charsWidth(text, flushIndex,flushLen);
if (flushLen>0 && nextX>=clipStart) {
if (bg!=null) {
paintBackground(x,y, nextX-x,height, g,
ascent, host, bg);
}
g.setColor(fg);
g.drawChars(text, flushIndex, flushLen, (int)x,(int)y);
}
if (host.getUnderlineForToken(this)) {
g.setColor(fg);
int y2 = (int)(y+1);
g.drawLine(origX,y2, (int)nextX,y2);
}
// Don't check if it's whitespace - some TokenMakers may return types
// other than Token.WHITESPACE for spaces (such as Token.IDENTIFIER).
// This also allows us to paint tab lines for MLC's.
if (host.getPaintTabLines() && origX==host.getMargin().left) {// && isWhitespace()) {
paintTabLines(origX, (int)y, (int)nextX, g, e, host);
}
return nextX;
}
}