Bug 434194: [painting] "Show whitespace character" option makes the
editor slow if there are many spaces
Space characters (and their visible place holders) are drawn with a
single call, not separately, if they are all of the same width.
Conflicts:
org.eclipse.jface.text/src/org/eclipse/jface/text/WhitespaceCharacterPainter.java
Change-Id: I29249a775030fe3f805b69a6265fff285a67eb22
Signed-off-by: John Hendrikx <hjohn@xs4all.nl>
diff --git a/org.eclipse.jface.text/src/org/eclipse/jface/text/WhitespaceCharacterPainter.java b/org.eclipse.jface.text/src/org/eclipse/jface/text/WhitespaceCharacterPainter.java
index 4a5bd8e..475b82a 100644
--- a/org.eclipse.jface.text/src/org/eclipse/jface/text/WhitespaceCharacterPainter.java
+++ b/org.eclipse.jface.text/src/org/eclipse/jface/text/WhitespaceCharacterPainter.java
@@ -1,5 +1,5 @@
/*******************************************************************************
- * Copyright (c) 2006, 2012 Wind River Systems, Inc., IBM Corporation and others.
+ * Copyright (c) 2006, 2017 Wind River Systems, Inc., IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
@@ -10,6 +10,7 @@
* Anton Leherbauer (Wind River Systems) - [painting] Long lines take too long to display when "Show Whitespace Characters" is enabled - https://bugs.eclipse.org/bugs/show_bug.cgi?id=196116
* Anton Leherbauer (Wind River Systems) - [painting] Whitespace characters not drawn when scrolling to right slowly - https://bugs.eclipse.org/bugs/show_bug.cgi?id=206633
* Tom Eicher (Avaloq Evolution AG) - block selection mode
+ * John Hendrikx - [painting] Performance improvement of space character rendering - https://bugs.eclipse.org/bugs/show_bug.cgi?id=434194
*******************************************************************************/
package org.eclipse.jface.text;
@@ -40,6 +41,9 @@
private static final char CARRIAGE_RETURN_SIGN= '\u00a4';
private static final char LINE_FEED_SIGN= '\u00b6';
+ private static final String SPACE_SIGN_STRING= String.valueOf(SPACE_SIGN);
+ private static final String IDEOGRAPHIC_SPACE_SIGN_STRING= String.valueOf(IDEOGRAPHIC_SPACE_SIGN);
+
/** Indicates whether this painter is active. */
private boolean fIsActive= false;
/** The source viewer this painter is attached to. */
@@ -215,6 +219,10 @@
*/
private void drawLineRange(GC gc, int startLine, int endLine, int x, int w) {
final int viewPortWidth= fTextWidget.getClientArea().width;
+ int spaceCharWidth= gc.stringExtent(" ").x; //$NON-NLS-1$
+ boolean spaceCharsAreSameWidth= spaceCharWidth == gc.stringExtent(SPACE_SIGN_STRING).x &&
+ spaceCharWidth == gc.stringExtent(IDEOGRAPHIC_SPACE_SIGN_STRING).x;
+
for (int line= startLine; line <= endLine; line++) {
int lineOffset= fTextWidget.getOffsetAtLine(line);
// line end offset including line delimiter
@@ -268,7 +276,7 @@
}
// draw character range
if (endOffset > startOffset) {
- drawCharRange(gc, startOffset, endOffset, lineOffset, lineEndOffset);
+ drawCharRange(gc, startOffset, endOffset, lineOffset, lineEndOffset, spaceCharsAreSameWidth);
}
}
}
@@ -285,8 +293,10 @@
* @param endOffset exclusive end index of the drawing range
* @param lineOffset inclusive start index of the line
* @param lineEndOffset exclusive end index of the line
+ * @param spaceCharsAreSameWidth whether or not all space chars are same width, if <code>true</code>
+ * rendering can be optimized
*/
- private void drawCharRange(GC gc, int startOffset, int endOffset, int lineOffset, int lineEndOffset) {
+ private void drawCharRange(GC gc, int startOffset, int endOffset, int lineOffset, int lineEndOffset, boolean spaceCharsAreSameWidth) {
StyledTextContent content= fTextWidget.getContent();
String lineText= content.getTextRange(lineOffset, lineEndOffset - lineOffset);
int startOffsetInLine= startOffset - lineOffset;
@@ -312,12 +322,12 @@
StyleRange styleRange= null;
Color fg= null;
- StringBuffer visibleChar= new StringBuffer(10);
+ StringBuilder visibleChar= new StringBuilder(10);
+ int delta= 0;
for (int textOffset= startOffsetInLine; textOffset <= endOffsetInLine; ++textOffset) {
- int delta= 0;
boolean eol= false;
+ delta++;
if (textOffset < endOffsetInLine) {
- delta= 1;
char c= lineText.charAt(textOffset);
switch (c) {
case ' ':
@@ -338,8 +348,12 @@
visibleChar.append(SPACE_SIGN);
}
}
- // 'continue' would improve performance but may produce drawing errors
- // for long runs of space if width of space and dot differ
+ // 'continue' improves performance but may produce drawing errors
+ // for long runs of space if width of space and dot differ, therefore
+ // it can be used only for monospace fonts
+ if (spaceCharsAreSameWidth) {
+ continue;
+ }
break;
case '\u3000': // ideographic whitespace
if (isEmptyLine) {
@@ -359,8 +373,12 @@
visibleChar.append(IDEOGRAPHIC_SPACE_SIGN);
}
}
- // 'continue' would improve performance but may produce drawing errors
- // for long runs of space if width of space and dot differ
+ // 'continue' improves performance but may produce drawing errors
+ // for long runs of space if width of space and dot differ, therefore
+ // it can be used only for monospace fonts
+ if (spaceCharsAreSameWidth) {
+ continue;
+ }
break;
case '\t':
if (isEmptyLine) {
@@ -397,12 +415,11 @@
eol= true;
break;
default:
- delta= 0;
break;
}
}
if (visibleChar.length() > 0) {
- int widgetOffset= startOffset + textOffset - startOffsetInLine - visibleChar.length() + delta;
+ int widgetOffset= startOffset + textOffset - startOffsetInLine - delta + 1;
if (!eol || !isFoldedLine(content.getLineAtOffset(widgetOffset))) {
/*
* Block selection is drawn using alpha and no selection-inverting
@@ -422,6 +439,7 @@
}
visibleChar.delete(0, visibleChar.length());
}
+ delta= 0;
}
}
