Printing comma-aligned doubles to printer device with Java

Question

For a project I need to print some numbers to the printer. They need to be printed below eachother, aligned on the comma. The font is not and can not be a monospaced one. I'm using a DecimalFormat("0.000") to transform all the numbers into strings ending in exactly 3 decimals.

What would be the correct way to align the numbers on the comma, below eachother? I'm using Java's Printable interface, as explained here http://docs.oracle.com/javase/tutorial/2d/printing/index.html.

Thanks

EDIT: I'm not trying to print to the console, but to a printer (the actual hardware thing where real paper comes out)

score 1 · Answer 1 · answered Feb 12 '13 at 14:27

1

This would certainly look better with a monospaced font.

I'm assuming that the comma is the decimal point. Here's what I would do.

Generate a comma image using drawString.
Break up the number into two parts, the number before the decimal, and the number after the decimal.
Generate the number images before the decimal and the number after the decimal using drawString.
After all the numbers are converted to images, go through the numbers after the decimal images to see which one has the longest width.
You now have the number of pixels of width for the longest numbers after the decimal, and the comma.
Go through the number images again, drawing your images on the printer canvas in the following order.
- Number after the decimal
- Comma
- Number before the decimal

answered Feb 12 '13 at 14:27

Gilbert Le Blanc

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Thanks for the advice. I tried to do something similar, splitting the number on the decimal point and printing the decimal part on a fixed point prefixed by a comma, and the prefixing the integer part. The problem is I can't figure out the anchor x for the integer part as it has variable length. I've tried `fontMetrics.charsWidth(...)` and throwing in the integer part of the number (as a string) as a parameter, but that doesn't work properly. I think I'm just going to emulate a monospaced font by defining a charwidth and iterating over the string.toCharArray(). Thanks again! – RDM Feb 12 '13 at 15:49
On a sidenote, I'm having trouble making the printer print monospaced (on a different project...). Sure enough I'm setting the graphics environment's font to a monospaced font (`new Font("Monospaced", Font.PLAIN, 12)`) which is producing monospaced prints on Mac but not on Windows. Is this a printer manufacturer driver issue or can I do anything about it? I've also tried the Courier and Consolas fonts. – RDM Feb 12 '13 at 16:05
1

http://stackoverflow.com/questions/11020978/monospaced-font-symbols-for-jtextpane – Gilbert Le Blanc Feb 12 '13 at 16:23
Thanks, this is more or less what I had though. I've tried setting the Font name to "Courier New" but I'm still struggling with it as now I don't get anything monospaced at all anymore, neither on Mac nor on Windows. – RDM Feb 12 '13 at 16:39

Mikhail Vladimirov · Answer 2 · 2013-02-12T14:34:45.013

0

Just convert them to aligned strings and then print these strings:

public static String align (String str)
{
    int n = str.indexOf('.');

    StringBuilder sb = new StringBuilder ();
    for (int i = n; i < 3; i++)
        sb.append ((char)0x2007); // Append FIGURE-SPACE character
    sb.append (str);
    return sb.toString ();
}

public static void main(String[] args) {
    Random r = new Random ();
    DecimalFormat format = new DecimalFormat("0.000");

    for (int i = 0; i < 10; i++)
    {
        String str = format.format(Math.pow (r.nextDouble(), 3.0) * 150.0); 
        System.out.println(align (str));
    }
}

edited Feb 12 '13 at 14:34

answered Feb 12 '13 at 14:10

Mikhail Vladimirov

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Unfortunately I'm not printing to the console, I'm printing to a printer device using graphics.drawString(String str, int x, int y), and the string str is printed starting at location x, y from left to right (so left-aligned). The console is monospaced and that would be easy... – RDM Feb 12 '13 at 14:14
Even in non-monospace fonts, all digits usually have the same width, and there is special unicode character "FIGURE-SPACE" (U+2007) that has the same width as digits. – Mikhail Vladimirov Feb 12 '13 at 14:32

Printing comma-aligned doubles to printer device with Java

2 Answers2