Need help calculating new line break width

[ozzyman]

Please look at the for loop in this print method.

I'm trying to find line breaks in a String of text that gets printed.
Then wherever there's a line break, i need to measure the width:
from start char position to line break char position
and then set layout to the nextLayout of that width.

At the moment all I can do is break too early & often.
I think there's something wrong with the width calculation.

Please have a look, any feedback would be greatly appreciated.

    public int print(Graphics g, PageFormat pf, int page) throws PrinterException {
        if (page > 0) return NO_SUCH_PAGE;
 
        Graphics2D g2d = (Graphics2D)g;
        g2d.translate(pf.getImageableX()+mmToPixel(padLeft), pf.getImageableY());
 
        as = new AttributedString(msg);
        paragraph = as.getIterator();
        paragraphStart = paragraph.getBeginIndex();
        paragraphEnd = paragraph.getEndIndex();
        frc = g2d.getFontRenderContext();
        lineMeasurer = new LineBreakMeasurer(paragraph, frc);
        drawPosY = 0;
 
        lineMeasurer.setPosition(paragraphStart);
        while (lineMeasurer.getPosition() < paragraphEnd) {
            int startPosition = lineMeasurer.getPosition();
            TextLayout [COLOR=seagreen]layout[/COLOR] = lineMeasurer.nextLayout(breakWidth);
 
            [COLOR=red]for[/COLOR] (int i=startPosition; i<lineMeasurer.getPosition(); i++) {
                if (msg.charAt(i) == '\n') {
                    lineMeasurer.setPosition(startPosition);
                    [COLOR=seagreen]layout[/COLOR] = lineMeasurer.nextLayout([COLOR=magenta]mmToPixel(i-startPosition)[/COLOR]);
                    break;
                }
            }
 
            drawPosX = layout.isLeftToRight()? 0 : breakWidth - layout.getAdvance();
 
            drawPosY += layout.getAscent();
            layout.draw(g2d, drawPosX, drawPosY);
            drawPosY += layout.getDescent() + layout.getLeading();
        }
        return PAGE_EXISTS;
    }

    private float mmToPixel(float mm) {
        return ((mm/10f)/2.54f)*72f;
    }

Thanks.

[DarrylBurke]

I've never really used those classes, but maybe you can glean something from this code I wrote about 2½ years ago in response to someone else's problem.

import java.awt.*;
import java.awt.font.*;
import java.text.AttributedString;
import java.util.ArrayList;
import javax.swing.*;

public class MultiLineText extends JComponent {

  private Font font = new Font("TimesRoman", Font.PLAIN, 12);
  private String[] breakText = {"John likes sweets.  Most of all, John likes icecream and chocolate.",
    "In contrast, Mary likes fruit.",
    "Especially bananas and strawberries."
  };
  private int wrapWidth = 110;
  private ArrayList<ArrayList<TextLayout>> layouts = new ArrayList<ArrayList<TextLayout>>();
  private TextLayout layout;

  public MultiLineText() {
    breakLines();
  }

  public void breakLines() {
    for (int j = 0; j < breakText.length; j++) {
      layouts.add(new ArrayList<TextLayout>());

      final AttributedString attStr = new AttributedString(breakText[j]);
      attStr.addAttribute(TextAttribute.FONT, font);
      final LineBreakMeasurer measurer =
              new LineBreakMeasurer(attStr.getIterator(),
              new FontRenderContext(null, true, true));

      while (null != (layout = measurer.nextLayout(wrapWidth))) {
        layouts.get(j).add(layout);
      }
    }
  }

  @Override
  public void paintComponent(Graphics g) {
    Graphics2D g2 = (Graphics2D) g;
    FontMetrics metrics = g2.getFontMetrics(font);

    int textHeight = metrics.getHeight();
    int left = textHeight; // only for symmetry, could be different

    for (int i = 0; i < layouts.size(); i++) {
      int top = textHeight;
      for (int j = 0; j < layouts.get(i).size(); j++) {
        layout = layouts.get(i).get(j);
        layout.draw(g2, left, top);

        top += textHeight;
      }
      left += wrapWidth + textHeight;
    }
  }

  public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {

      @Override
      public void run() {
        JFrame frame = new JFrame("Multi Line Text");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(600, 400);
        frame.setLocationRelativeTo(null);
        frame.setResizable(false);

        frame.add(new MultiLineText());
        frame.setVisible(true);
      }
    });
  }
}

db

[ozzyman]

Without the for loop I get this print output:

Menu 2 (4/0): [2] £ 15.60 Menu 14
(9/0): [14] £ 124.41 GT: £ 140.01 (£
0.00)VOID: £ 0.00NET: £ 140.01

I now changed the for loop to this (added FontMetrics):

            for (int i=startPosition; i<lineMeasurer.getPosition(); i++) {
                if (msg.charAt(i) == '\n') {
                    lineMeasurer.setPosition(startPosition);
                    FontMetrics metrics = g.getFontMetrics();
                    int width = metrics.stringWidth(msg.substring(startPosition, i));
                    layout = lineMeasurer.nextLayout(mmToPixel(width));
                    break;
                }
            }

and the print output was this:

Menu 2 (4/0): [2] £ 15.60 Menu 13 (9/0):
[13] £ 124.41 GT: £ 140.01 (£ 0.00)
VOID: £ 0.00NET: £ 140.01

but i want the print output to come out like this:

Menu 2 (4/0):
[2] £ 15.60
Menu 14 (9/0):
[14] £ 124.41
GT: £ 140.01 (£ 0.00)
VOID: £ 0.00
NET: £ 140.01

[ozzyman]

Thanks Darryl, I'll have a look... it looks good

Edit:

Ahh, I saw that you created a list of TextLayouts before hand and then used those.
And then I realised it would've been so much easier to break the text before-hand like you did,
each line into a new array, and each string in the array having its own TextLayout.

Thanks so much...problem should be sorted in no time :)

Edit:

perfecto :)