org.bidib.wizard.highlight.TextLineNumber Maven / Gradle / Ivy
package org.bidib.wizard.highlight;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.Point;
import java.awt.Rectangle;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.HashMap;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.border.Border;
import javax.swing.border.CompoundBorder;
import javax.swing.border.EmptyBorder;
import javax.swing.border.MatteBorder;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.Element;
import javax.swing.text.JTextComponent;
import javax.swing.text.StyleConstants;
import javax.swing.text.Utilities;
/**
* This class will display line numbers for a related text component. The text component must use the same line height
* for each line. TextLineNumber supports wrapped lines and will highlight the line number of the current line in the
* text component.
*
* This class was designed to be used as a component added to the row header of a JScrollPane.
*/
public class TextLineNumber extends JPanel implements CaretListener, DocumentListener, PropertyChangeListener {
private static final long serialVersionUID = 1L;
public final static float LEFT = 0.0f;
public final static float CENTER = 0.5f;
public final static float RIGHT = 1.0f;
private final static Border OUTER = new MatteBorder(0, 0, 0, 2, Color.GRAY);
private final static int HEIGHT = Integer.MAX_VALUE - 1000000;
// Text component this TextTextLineNumber component is in sync with
private JTextComponent component;
// Properties that can be changed
private boolean updateFont;
private int borderGap;
private Color currentLineForeground;
private float digitAlignment;
private int minimumDisplayDigits;
// Keep history information to reduce the number of times the component
// needs to be repainted
private int lastDigits;
private int lastHeight;
private int lastLine;
private HashMap fonts;
/**
* Create a line number component for a text component. This minimum display width will be based on 3 digits.
*
* @param component
* the related text component
*/
public TextLineNumber(JTextComponent component) {
this(component, 3);
}
/**
* Create a line number component for a text component.
*
* @param component
* the related text component
* @param minimumDisplayDigits
* the number of digits used to calculate the minimum width of the component
*/
public TextLineNumber(JTextComponent component, int minimumDisplayDigits) {
this.component = component;
setFont(component.getFont());
setBorderGap(5);
setCurrentLineForeground(Color.RED);
setDigitAlignment(RIGHT);
setMinimumDisplayDigits(minimumDisplayDigits);
component.getDocument().addDocumentListener(this);
component.addCaretListener(this);
component.addPropertyChangeListener("font", this);
}
/**
* Gets the update font property
*
* @return the update font property
*/
public boolean getUpdateFont() {
return updateFont;
}
/**
* Set the update font property. Indicates whether this Font should be updated automatically when the Font of the
* related text component is changed.
*
* @param updateFont
* when true update the Font and repaint the line numbers, otherwise just repaint the line numbers.
*/
public void setUpdateFont(boolean updateFont) {
this.updateFont = updateFont;
}
/**
* Gets the border gap
*
* @return the border gap in pixels
*/
public int getBorderGap() {
return borderGap;
}
/**
* The border gap is used in calculating the left and right insets of the border. Default value is 5.
*
* @param borderGap
* the gap in pixels
*/
public void setBorderGap(int borderGap) {
this.borderGap = borderGap;
Border inner = new EmptyBorder(0, borderGap, 0, borderGap);
setBorder(new CompoundBorder(OUTER, inner));
lastDigits = 0;
setPreferredWidth();
}
/**
* Gets the current line rendering Color
*
* @return the Color used to render the current line number
*/
public Color getCurrentLineForeground() {
return currentLineForeground == null ? getForeground() : currentLineForeground;
}
/**
* The Color used to render the current line digits. Default is Coolor.RED.
*
* @param currentLineForeground
* the Color used to render the current line
*/
public void setCurrentLineForeground(Color currentLineForeground) {
this.currentLineForeground = currentLineForeground;
}
/**
* Gets the digit alignment
*
* @return the alignment of the painted digits
*/
public float getDigitAlignment() {
return digitAlignment;
}
/**
* Specify the horizontal alignment of the digits within the component. Common values would be:
*
* - TextLineNumber.LEFT
*
- TextLineNumber.CENTER
*
- TextLineNumber.RIGHT (default)
*
*
* @param currentLineForeground
* the Color used to render the current line
*/
public void setDigitAlignment(float digitAlignment) {
this.digitAlignment = digitAlignment > 1.0f ? 1.0f : digitAlignment < 0.0f ? -1.0f : digitAlignment;
}
/**
* Gets the minimum display digits
*
* @return the minimum display digits
*/
public int getMinimumDisplayDigits() {
return minimumDisplayDigits;
}
/**
* Specify the mimimum number of digits used to calculate the preferred width of the component. Default is 3.
*
* @param minimumDisplayDigits
* the number digits used in the preferred width calculation
*/
public void setMinimumDisplayDigits(int minimumDisplayDigits) {
this.minimumDisplayDigits = minimumDisplayDigits;
setPreferredWidth();
}
/**
* Calculate the width needed to display the maximum line number
*/
private void setPreferredWidth() {
Element root = component.getDocument().getDefaultRootElement();
int lines = root.getElementCount();
int digits = Math.max(String.valueOf(lines).length(), minimumDisplayDigits);
// Update sizes when number of digits in the line number changes
if (lastDigits != digits) {
lastDigits = digits;
FontMetrics fontMetrics = getFontMetrics(getFont());
int width = fontMetrics.charWidth('0') * digits;
Insets insets = getInsets();
int preferredWidth = insets.left + insets.right + width;
Dimension d = getPreferredSize();
d.setSize(preferredWidth, HEIGHT);
setPreferredSize(d);
setSize(d);
}
}
/**
* Draw the line numbers
*/
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
// Determine the width of the space available to draw the line number
FontMetrics fontMetrics = component.getFontMetrics(component.getFont());
Insets insets = getInsets();
int availableWidth = getSize().width - insets.left - insets.right;
// Determine the rows to draw within the clipped bounds.
Rectangle clip = g.getClipBounds();
int rowStartOffset = component.viewToModel(new Point(0, clip.y));
int endOffset = component.viewToModel(new Point(0, clip.y + clip.height));
while (rowStartOffset <= endOffset) {
try {
if (isCurrentLine(rowStartOffset))
g.setColor(getCurrentLineForeground());
else
g.setColor(getForeground());
// Get the line number as a string and then determine the
// "X" and "Y" offsets for drawing the string.
String lineNumber = getTextLineNumber(rowStartOffset);
int stringWidth = fontMetrics.stringWidth(lineNumber);
int x = getOffsetX(availableWidth, stringWidth) + insets.left;
int y = getOffsetY(rowStartOffset, fontMetrics);
g.drawString(lineNumber, x, y);
// Move to the next row
rowStartOffset = Utilities.getRowEnd(component, rowStartOffset) + 1;
}
catch (Exception e) {
break;
}
}
}
/*
* We need to know if the caret is currently positioned on the line we are about to paint so the line number can be
* highlighted.
*/
private boolean isCurrentLine(int rowStartOffset) {
int caretPosition = component.getCaretPosition();
Element root = component.getDocument().getDefaultRootElement();
if (root.getElementIndex(rowStartOffset) == root.getElementIndex(caretPosition))
return true;
else
return false;
}
/*
* Get the line number to be drawn. The empty string will be returned when a line of text has wrapped.
*/
protected String getTextLineNumber(int rowStartOffset) {
Element root = component.getDocument().getDefaultRootElement();
int index = root.getElementIndex(rowStartOffset);
Element line = root.getElement(index);
if (line.getStartOffset() == rowStartOffset)
return String.valueOf(index + 1);
else
return "";
}
/*
* Determine the X offset to properly align the line number when drawn
*/
private int getOffsetX(int availableWidth, int stringWidth) {
return (int) ((availableWidth - stringWidth) * digitAlignment);
}
/*
* Determine the Y offset for the current row
*/
private int getOffsetY(int rowStartOffset, FontMetrics fontMetrics) throws BadLocationException {
// Get the bounding rectangle of the row
Rectangle r = component.modelToView(rowStartOffset);
int lineHeight = fontMetrics.getHeight();
int y = r.y + r.height;
int descent = 0;
// The text needs to be positioned above the bottom of the bounding
// rectangle based on the descent of the font(s) contained on the row.
if (r.height == lineHeight) // default font is being used
{
descent = fontMetrics.getDescent();
}
else // We need to check all the attributes for font changes
{
if (fonts == null)
fonts = new HashMap();
Element root = component.getDocument().getDefaultRootElement();
int index = root.getElementIndex(rowStartOffset);
Element line = root.getElement(index);
for (int i = 0; i < line.getElementCount(); i++) {
Element child = line.getElement(i);
AttributeSet as = child.getAttributes();
String fontFamily = (String) as.getAttribute(StyleConstants.FontFamily);
Integer fontSize = (Integer) as.getAttribute(StyleConstants.FontSize);
String key = fontFamily + fontSize;
FontMetrics fm = fonts.get(key);
if (fm == null) {
Font font = new Font(fontFamily, Font.PLAIN, fontSize);
fm = component.getFontMetrics(font);
fonts.put(key, fm);
}
descent = Math.max(descent, fm.getDescent());
}
}
return y - descent;
}
//
// Implement CaretListener interface
//
@Override
public void caretUpdate(CaretEvent e) {
// Get the line the caret is positioned on
int caretPosition = component.getCaretPosition();
Element root = component.getDocument().getDefaultRootElement();
int currentLine = root.getElementIndex(caretPosition);
// Need to repaint so the correct line number can be highlighted
if (lastLine != currentLine) {
repaint();
lastLine = currentLine;
}
}
//
// Implement DocumentListener interface
//
@Override
public void changedUpdate(DocumentEvent e) {
documentChanged();
}
@Override
public void insertUpdate(DocumentEvent e) {
documentChanged();
}
@Override
public void removeUpdate(DocumentEvent e) {
documentChanged();
}
/*
* A document change may affect the number of displayed lines of text. Therefore the lines numbers will also change.
*/
private void documentChanged() {
// View of the component has not been updated at the time
// the DocumentEvent is fired
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
try {
int endPos = component.getDocument().getLength();
Rectangle rect = component.modelToView(endPos);
if (rect != null && rect.y != lastHeight) {
setPreferredWidth();
repaint();
lastHeight = rect.y;
}
}
catch (BadLocationException ex) { /* nothing to do */
}
}
});
}
//
// Implement PropertyChangeListener interface
//
@Override
public void propertyChange(PropertyChangeEvent evt) {
if (evt.getNewValue() instanceof Font) {
if (updateFont) {
Font newFont = (Font) evt.getNewValue();
setFont(newFont);
lastDigits = 0;
setPreferredWidth();
}
else {
repaint();
}
}
}
}
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