WIP fix for #160 - Configurable Line Height. This currently makes the line height configurable when word wrap is NOT enabled. Line number list is also updated. Fold indicators do not currently work properly - they only update in the demo app because I've tied '8' and '9' keypresses to tweaking the line height for quick testing. I think what still needs to be done is: fold indicator immediate updating, fold indicator rendering of 'active' fold line, and *everything* when word wrap is enabled

Author: bobbylight

RSyntaxTextArea/src/main/java/org/fife/ui/rsyntaxtextarea/RSyntaxTextArea.java

@@ -1044,6 +1044,18 @@ public boolean forceReparsing(Parser parser) {
 	}
 
 
+	/**
+	 * Overridden to return account for all fonts being used
+	 * when determining the line height.
+	 *
+	 * @return The line height.
+	 */
+	@Override
+	public int getActualLineHeight() {
+		return lineHeight;
+	}
+
+
 	/**
 	 * Returns whether bracket matching should be animated.
 	 *
@@ -1411,17 +1423,6 @@ public int getLastVisibleOffset() {
 	}
 
 
-	/**
-	 * Returns the height to use for a line of text in this text area.
-	 *
-	 * @return The height of a line of text in this text area.
-	 */
-	@Override
-	public int getLineHeight() {
-		return lineHeight;
-	}
-
-
 	public LinkGenerator getLinkGenerator() {
 		return linkGenerator;
 	}

RSyntaxTextArea/src/main/java/org/fife/ui/rsyntaxtextarea/SyntaxView.java

@@ -736,10 +736,13 @@ public void paint(Graphics g, Shape a) {
 		int heightAbove = clip.y - alloc.y;
 		int linesAbove = Math.max(0, heightAbove / lineHeight);
 
+		// Top and bottom spacing around font if line height > font size
+		int verticalSpacing = (lineHeight - host.getActualLineHeight()) / 2;
+
 		FoldManager fm = host.getFoldManager();
 		linesAbove += fm.getHiddenLineCountAbove(linesAbove, true);
 		Rectangle lineArea = lineToRect(a, linesAbove);
-		int y = lineArea.y + ascent;
+		int y = lineArea.y + verticalSpacing + ascent;
 		int x = lineArea.x;
 		Element map = getElement();
 		int lineCount = map.getElementCount();
@@ -790,8 +793,8 @@ public void paint(Graphics g, Shape a) {
 				Color c = RSyntaxUtilities.getFoldedLineBottomColor(host);
 				if (c!=null) {
 					g.setColor(c);
-					g.drawLine(x,y+lineHeight-ascent-1,
-							host.getWidth(),y+lineHeight-ascent-1);
+					int lineY = y - verticalSpacing - ascent + lineHeight - 1;
+					g.drawLine(x, lineY, host.getWidth(), lineY);
 				}
 
 				// Skip to next line to paint, taking extra care for lines with

RSyntaxTextArea/src/main/java/org/fife/ui/rtextarea/FoldIndicator.java

@@ -485,7 +485,7 @@ protected void paintComponent(Graphics g) {
 		int topLine = (visibleRect.y-textAreaInsets.top)/cellHeight;
 		int y = topLine*cellHeight +
 			(cellHeight-collapsedFoldIcon.getIconHeight())/2;
-		y += textAreaInsets.top;
+		y += textAreaInsets.top - 1;
 
 		// Get the first and last lines to paint.
 		FoldManager fm = rsta.getFoldManager();
@@ -521,7 +521,7 @@ protected void paintComponent(Graphics g) {
 						if (paintingOutlineLine) {
 							g.setColor(getForeground());
 							int w2 = width / 2;
-							g.drawLine(w2, y + cellHeight / 2, w2, y + cellHeight);
+							g.drawLine(w2, y, w2, y + cellHeight / 2);
 						}
 					}
 					if (mouseOverFoldIcon) {

RSyntaxTextArea/src/main/java/org/fife/ui/rtextarea/Gutter.java

@@ -1224,10 +1224,12 @@ public void propertyChange(PropertyChangeEvent e) {
 
 			String name = e.getPropertyName();
 
-			// If they change the text area's font, we need to update cell
-			// heights to match the font's height.
+			// If they change the text area's font, or any other property
+			// related to line height, we need to update cell heights to
+			// match the font's height.
 			if ("font".equals(name) ||
-					RSyntaxTextArea.SYNTAX_SCHEME_PROPERTY.equals(name)) {
+					RSyntaxTextArea.SYNTAX_SCHEME_PROPERTY.equals(name) ||
+					RTextArea.LINE_HEIGHT_MULTIPLIER_PROPERTY.equals(name)) {
 				for (int i=0; i<getComponentCount(); i++) {
 					AbstractGutterComponent agc =
 								(AbstractGutterComponent)getComponent(i);

RSyntaxTextArea/src/main/java/org/fife/ui/rtextarea/LineNumberList.java

@@ -377,6 +377,9 @@ protected void paintComponent(Graphics g) {
 			return;
 		}
 
+		// Top and bottom spacing around font if line height > font size
+		int verticalSpacing = (cellHeight - textArea.getActualLineHeight()) / 2;
+
 		// Get where to start painting (top of the row), and where to paint
 		// the line number (drawString expects y==baseline).
 		// We need to be "scrolled up" just enough for the missing part of
@@ -388,7 +391,7 @@ protected void paintComponent(Graphics g) {
 		}
 		int topLine = (visibleRect.y-textAreaInsets.top)/cellHeight;
 		int actualTopY = topLine*cellHeight + textAreaInsets.top;
-		int y = actualTopY + ascent;
+		int y = actualTopY + verticalSpacing + ascent;
 
 		// Get the actual first line to paint, taking into account folding.
 		FoldManager fm = null;
@@ -726,9 +729,9 @@ public void setTextArea(RTextArea textArea) {
 
 
 	/**
-	 * Changes the height of the cells in the JList so that they are as tall as
-	 * font. This function should be called whenever the user changes the Font
-	 * of <code>textArea</code>.
+	 * Changes the height of the cells in this component so that they are as
+	 * tall as the font. This function should be called whenever the user
+	 * changes the Font of <code>textArea</code>.
 	 */
 	private void updateCellHeights() {
 		if (textArea!=null) {
@@ -744,8 +747,8 @@ private void updateCellHeights() {
 
 
 	/**
-	 * Changes the width of the cells in the JList so you can see every digit
-	 * of each.
+	 * Changes the width of the cells in this component so you can see every
+	 * digit of each.
 	 */
 	void updateCellWidths() {
 

RSyntaxTextArea/src/main/java/org/fife/ui/rtextarea/RTextAreaBase.java

@@ -48,6 +48,7 @@ public abstract class RTextAreaBase extends JTextArea {
 	public static final String CURRENT_LINE_HIGHLIGHT_COLOR_PROPERTY	= "RTA.currentLineHighlightColor";
 	public static final String CURRENT_LINE_HIGHLIGHT_FADE_PROPERTY	= "RTA.currentLineHighlightFade";
 	public static final String HIGHLIGHT_CURRENT_LINE_PROPERTY		= "RTA.currentLineHighlight";
+	public static final String LINE_HEIGHT_MULTIPLIER_PROPERTY		= "RTA.lineHeightMultiplier";
 	public static final String ROUNDED_SELECTION_PROPERTY			= "RTA.roundedSelection";
 
 	private boolean tabsEmulatedWithSpaces;		// If true, tabs will be expanded to spaces.
@@ -60,6 +61,7 @@ public abstract class RTextAreaBase extends JTextArea {
 	private int marginSizeInChars;			// How many 'm' widths the margin line is over.
 	private boolean fadeCurrentLineHighlight;	// "Fade effect" for current line highlight.
 	private boolean roundedSelectionEdges;
+	private float lineHeightMultiplier;
 	private int previousCaretY;
 	int currentCaretY;							// Used to know when to highlight current line.
 
@@ -311,6 +313,21 @@ protected void forceCurrentLineHighlightRepaint() {
 	}
 
 
+	/**
+	 * Returns the actual height of a line of text in this editor.  This
+	 * is essentially the font height.  There may be additional space
+	 * between lines; to get the actual, full height of a line, see
+	 * {@link #getLineHeight()}.
+	 *
+	 * @return The height of a line of text, not including any extra
+	 *         spacing.
+	 * @see #getLineHeight()
+	 */
+	public int getActualLineHeight() {
+		return getRowHeight();
+	}
+
+
 	/**
 	 * Returns the <code>java.awt.Color</code> used as the background color for
 	 * this text area.  If a <code>java.awt.Image</code> image is currently
@@ -532,11 +549,32 @@ public final int getLineEndOffsetOfCurrentLine() {
 
 	/**
 	 * Returns the height of a line of text in this text area.
+	 * This may be larger than the height of the font if extra
+	 * spacing is requested between lines.<p>
+	 * This is equal to the font's height times the line height
+	 * multiplier.
 	 *
 	 * @return The height of a line of text.
+	 * @see #getLineHeightMultiplier()
+	 * @see #getActualLineHeight()
 	 */
 	public int getLineHeight() {
-		return getRowHeight();
+		return (int)(getActualLineHeight() * lineHeightMultiplier);
+	}
+
+
+	/**
+	 * Returns a multiplier used to determine a line's height.
+	 * This is multiplied by the font height to determine how
+	 * tall each line of text is.  This can be used to add
+	 * extra whitespace between each line.
+	 *
+	 * @return The line height multiplier.
+	 * @see #setLineHeightMultiplier(float)
+	 * #see #getLineHeight()
+	 */
+	public float getLineHeightMultiplier() {
+		return lineHeightMultiplier;
 	}
 
 
@@ -631,6 +669,7 @@ protected void init() {
 		enableEvents(AWTEvent.COMPONENT_EVENT_MASK|AWTEvent.KEY_EVENT_MASK);
 
 		// Defaults for various properties.
+		lineHeightMultiplier = 1;
 		setHighlightCurrentLine(true);
 		setCurrentLineHighlightColor(getDefaultCurrentLineHighlightColor());
 		setMarginLineEnabled(false);
@@ -972,6 +1011,35 @@ public void setHighlightCurrentLine(boolean highlight) {
 	}
 
 
+	/**
+	 * Sets the line height multiplier.
+	 * This is multiplied by the font height to determine how
+	 * tall each line of text is.  This can be used to add
+	 * extra whitespace between each line.
+	 *
+	 * @param multiplier The new multiplier value.  This
+	 *        should be between {@code 0.9} and {code 3},
+	 *        inclusive.
+	 * @see #getLineHeightMultiplier()
+	 * @see #getLineHeight()
+	 */
+	public void setLineHeightMultiplier(float multiplier) {
+
+		if (multiplier < 0.9 || multiplier > 3) {
+			throw new IllegalArgumentException("Invalid multiplier: " +
+				multiplier);
+		}
+
+		if (multiplier != lineHeightMultiplier) {
+			float old = lineHeightMultiplier;
+			lineHeightMultiplier = multiplier;
+			firePropertyChange(LINE_HEIGHT_MULTIPLIER_PROPERTY, old,
+				multiplier);
+			repaint();
+		}
+	}
+
+
 	/**
 	 * Sets whether word wrap is enabled.  This is overridden so that
 	 * the "current line highlight" gets updated if it needs to be.

RSyntaxTextAreaDemo/src/main/java/org/fife/ui/rsyntaxtextarea/demo/DemoRootPane.java

@@ -261,6 +261,21 @@ private RSyntaxTextArea createTextArea() {
 
 			im.put(KeyStroke.getKeyStroke(KeyEvent.VK_E, ctrlShift), "copyAsStyledTextEclipse");
 			am.put("copyAsStyledTextEclipse", createCopyAsStyledTextAction("eclipse"));
+
+			im.put(KeyStroke.getKeyStroke(KeyEvent.VK_8, 0), "inc");
+			am.put("inc", new AbstractAction() {
+				@Override
+				public void actionPerformed(ActionEvent e) {
+					textArea.setLineHeightMultiplier(textArea.getLineHeightMultiplier() + 0.1f);
+				}
+			});
+			im.put(KeyStroke.getKeyStroke(KeyEvent.VK_9, 0), "dec");
+			am.put("dec", new AbstractAction() {
+				@Override
+				public void actionPerformed(ActionEvent e) {
+					textArea.setLineHeightMultiplier(textArea.getLineHeightMultiplier() - 0.1f);
+				}
+			});
 		} catch (IOException ioe) {
 			ioe.printStackTrace();
 		}