[news.eclipse.platform.swt] printing gradient fill produces huge print s

[Dag Rende <dag.s@xxxxxxxx>]

Hi,

I make a modeling program that just got new improved graphical look on 
the models.
After a while reports started coming in from customers that couldn't 
print the models anymore. The cause were that printing produced too much 
data for the printers to cope with. The actual problem was that we used 
gradient fills in the models, and that the printing system sent huge bit 
maps for each gradient figure. Is this really necessary? If I draw a 
gradient fill in other programs the print data could be some kilobytes, 
so the printer knows how to generate gradients itself.

Here is a simple example that demonstrates the problem:

For a HP LaserJet 4200 printer, running with "... if (false) ..." (no 
gradient) produces 480bytes of print data. Running with "... if (true) 
..." (gradient) produces 15.8MB print data!


To run the example just open an eclipse and paste the code below into 
the package explorer and a new project with the java class for the file 
is created. Then open the Java Build Path property dialog, click Add 
variable..., select ECLIPSE_HOME, click extend and select 
plugins/org.eclipse.swt_3.3.2.v3349d.jar and 
plugins/org.eclipse.swt.win32.win32.x86_3.3.3.v3349.jar and click all OKs.

Here is the example code:

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.printing.PrintDialog;
import org.eclipse.swt.printing.Printer;
import org.eclipse.swt.printing.PrinterData;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class SimplePrint {
	public static void main(String[] args) {
		Display display = new Display();
		Shell shell = new Shell(display);
		shell.pack();
		shell.open();
		PrintDialog dialog = new PrintDialog(shell);
		PrinterData printerData = dialog.open();
		if (printerData != null) {
			Printer printer = new Printer(printerData);
			if (printer.startJob("Text")) {
				GC gc = new GC(printer);
				if (printer.startPage()) {
					if (false) {
						gc.fillGradientRectangle(200, 500, 4000, 4000, true);
					} else {
						gc.setBackground(display
								.getSystemColor(SWT.COLOR_BLACK));
						gc.fillRectangle(200, 500, 4000, 4000);
					}
					printer.endPage();
				}
				gc.dispose();
				printer.endJob();
			}
			printer.dispose();
			System.out.println("Print job done.");
		}
		while (!shell.isDisposed()) {
			if (!display.readAndDispatch()) {
				display.sleep();
			}
		}
		display.dispose();
	}
}