Re: speed up print(Graphics g, PageFormat pf, int pageIndex)
"Steve W. Jackson" <stevewjackson@charter.net> je napisao u poruci
interesnoj grupi:stevewjackson-E87424.13263915052006@individual.net...
In article <e46pkj$q0g$1@ss408.t-com.hr>, "Dado" <mario_zupan@inet.hr>
wrote:
I
In a Printable/Pageable class print(Graphics g, PageFormat pf, int
pageIndex) is calling x times as is needed to send graphics to a
printer.
It is pretty slow. What I need to change in a print method to get better
printing perforamnce?
There's not anything at all you can do about the fact that this method
will be called some number of times. So your focus is probably best
applied to making sure that the work the method does is as fast as
possible.
In our app, we have an object that implements those two interfaces.
When instantiated (which we do in a thread), it goes through our
Do you mean that you put creating printable class:
Print print = new Print();
in a thread, or only job.print() ?
underlying data to map the pages to page numbers. Because of the nature
of what we're printing, we can't render each page in advance to a
BufferedImage without having memory issues. Instead, each call to the
print method is used to find the appropriate references and render it at
that time, making it slower than we'd like.
But that's the key area to focus on for improved speed. If your data to
print is not going to break the bank, as it were, in terms of memory
needs, you can keep it handy, much like a double-buffering approach for
a Swing component, and simply draw each page on request to the Graphics
item provided in this method. At the very least, however, you could
render a page and keep it around so that the next call for the same page
number won't have to repeat the work and you could simply draw the same
thing the next time around.
= Steve =
--
Steve W. Jackson
Montgomery, Alabama
I have to print a chart (gantt) that can grow on a dozen pages. So I think
that keeping every page in a BufferedImage will cause an OutOfMemory. So,
probably I don't have any chance to speed my printing.
This is my Printable class (print method):
public class Print extends JPanel implements ActionListener, Printable{
...
public int print(Graphics pg, PageFormat pageFormat,
int pageIndex) throws PrinterException {
Graphics2D g2d = (Graphics2D) pg;
int m_maxNumPage = 7;
if (pageIndex >= m_maxNumPage)
return NO_SUCH_PAGE;
pg.translate((int)pageFormat.getImageableX(),
(int)pageFormat.getImageableY());
int wPage = (int)pageFormat.getImageableWidth();
int hPage = (int)pageFormat.getImageableHeight();
int w = poX.intValue();
int h = poY.intValue();
if (w == 0 || h == 0)
return NO_SUCH_PAGE;
int nCol = Math.max((int)Math.ceil((double)w/wPage), 1);
int nRow = Math.max((int)Math.ceil((double)h/hPage), 1);
m_maxNumPage = nCol*nRow;
int iCol = pageIndex % nCol;
int iRow = pageIndex / nCol;
int x = iCol*wPage;
int y = iRow*hPage;
int wImage = Math.min(wPage, w-x);
int hImage = Math.min(hPage, h-y);
drawGantt(g2d);
System.gc();
return PAGE_EXISTS;
}
....
}