My while loop for determining an appropriate font size is going too far... sometimes?

Question

I'm doing a project for school that requires me to read a file and make a bar graph with the data read. I have made a class that makes a JFrame and paints rectangles to divide the frame into a section for the name of each data (football player name) and one for the bars (age of player). I have a method that is meant to increase a font size until the longest (printed) string takes up the width that is allotted space, and return a font of that size to be used in the paint method.

It works when the initial JFrame is created, but as I resize it, it sometimes increases the font size 1 to large, but not always. I am at a loss. The console output shows (to me) that the condition of my while loop was not met, but the font size was still increased... any insight would be greatly appreciated. Thanks!

private Font myFont(int allowedW, int allowedH, int numData) {
    // needs to check length of font and size of JFrame and set font (size)
    // accordingly
    String longest = "";
    int fontSize = 1;
    Font f = new Font("SansSerif", Font.BOLD, fontSize);
    for (BarData b : this.graphData) {
        if (getFontMetrics(f).stringWidth(b.getName()) > getFontMetrics(f)
                .stringWidth(longest)) {
            longest = b.getName();
        }
    }
    while ((getFontMetrics(f).stringWidth(longest) < allowedW)){
            //&& ((getFontMetrics(f).getHeight() * numData) < allowedH)) {
            f = new Font("SansSerif", Font.BOLD, fontSize);
        System.out.println(longest);
        System.out.println("length " + getFontMetrics(f).stringWidth(longest));
        System.out.println("allowed width " + allowedW);
        System.out.println(fontSize);
        fontSize++;
    }
    return f;
}

output looks something like this when i drag to resize the jframe:

Demaryius Thomas
length 150
allowed width 158
17
Demaryius Thomas
length 170
allowed width 158
18

The `f` returned is not the largest font size that's less than `allowedW`, but actually the next one, which may be 1 too large. — jingx, Jun 08 '18 at 02:45
Your code always returns a font that is one size larger than allowed. After the while loop, create a Font object with size `fontSize-1` and return that. — Erwin Bolwidt, Jun 08 '18 at 02:45
I have tried adding f = new Font("SansSerif", Font.BOLD, fontSize - 1); after the while loop but it doesn't change anything... — Matthew Mayfield, Jun 08 '18 at 02:53
For better help sooner, post a [MCVE] or [Short, Self Contained, Correct Example](http://www.sscce.org/). — Andrew Thompson, Jun 08 '18 at 10:01
BTW - `new Font("SansSerif", Font.BOLD, fontSize)` use the constant for compile time checking. I.E. `new Font(Font.SANS_SERIF, Font.BOLD, fontSize)` — Andrew Thompson, Jun 08 '18 at 10:03

Gaurav Bansal · Accepted Answer · 2018-06-08T03:02:37.183

1

Change your while loop like this,

while ((getFontMetrics(f).stringWidth(longest) < allowedW)){
            //&& ((getFontMetrics(f).getHeight() * numData) < allowedH)) {
        System.out.println(longest);
        System.out.println("length " + getFontMetrics(f).stringWidth(longest));
        System.out.println("allowed width " + allowedW);
        System.out.println(fontSize);
        fontSize++;
        f = new Font("SansSerif", Font.BOLD, fontSize);//your f is not updated after increasing fontSize, if you put it as first statement.
    }
return new Font("SansSerif", Font.BOLD, fontSize - 1);

edited Jun 08 '18 at 03:02

answered Jun 08 '18 at 02:50

Gaurav Bansal

604
5
11

That's a nicer way to write the loop but it still returns a font that is one size too large. – Erwin Bolwidt Jun 08 '18 at 02:53
yes, but then your return statement should be like this, return new Font("SansSerif", Font.BOLD, fontSize - 1); In your earlier code it will not work, but now it should. – Gaurav Bansal Jun 08 '18 at 03:00

My while loop for determining an appropriate font size is going too far... sometimes?

1 Answers1