How can I improve Java2D performance of TextLayout.draw(..) - performance

Question

I'm using the Java2D TextLayout class together with a LineBreakMeasurer and an AttributedCharacterIterator to draw a piece of text into a box. The text is wrapped.
Profiling shows me that the code is very slow. Most of the time is lost in the method TextLayout.draw(..).
Does anyone have a suggestion for speed improvement?
// Get iterator for string
AttributedCharacterIterator iterator = attribText.getIterator();
// Create measurer
LineBreakMeasurer measurer = new LineBreakMeasurer(iterator, context);
// loop over the lines
int i = 1;
while (measurer.getPosition() < iterator.getEndIndex()) {
// Get line
TextLayout textLayout = measurer.nextLayout(w);
// get measurements
float ascent = textLayout.getAscent();
float descent = textLayout.getDescent();
float leading = textLayout.getLeading();
float size = ascent + descent;
// Move down to baseline
if( i == 1 ) {
if( coverType == CoverType.SPINE ) {
y = (box.height-size)/2;
y -= (size+leading)*(lines-1)/2;
} else if( vAlign == Alignment.Center ) {
y += (h-size)/2-(size+leading)*(lines-1)/2;
} else if( vAlign == Alignment.Bottom ) {
y += (h-size) - (size+leading)*(lines-1);
}
}
y += ascent;
// calculate starting point for alignment
float paintX = x;
switch( hAlign ) {
case Right: {
paintX = x + w - textLayout.getVisibleAdvance();
break;
}
case Center: {
paintX = x + (w - textLayout.getVisibleAdvance())/2;
break;
}
}
// Draw line
textLayout.draw(g2d, paintX, y);
// Move down to top of next line
y += descent + leading;
i++;
}
The relevant code snippet is shown above. attribText is an AttributtedString set before. context is the g2d.getFontRenderContext().

Answer 1

This post is rather old now so I hope you have found a solution that works for your needs. If you haven't here is something to think about. You only need to draw the text that is within the visible region. Since you know the y coordinate of each line it is easy to check to see if the y lies within the bounds of getVisibleRect(). Only painting the text that is necessary greatly improves performance (assuming of course that your text is longer than a single page).