How to change the size of the font of a JLabel to take the maximum size
containers, fonts, java, jlabel, size
Solution
Not the most pretty code, but the following will pick an appropriate font size for a `JLabel` called `label` such that the text inside will fit the interior as much as possible without overflowing the label:
Font labelFont = label.getFont();
String labelText = label.getText();
int stringWidth = label.getFontMetrics(labelFont).stringWidth(labelText);
int componentWidth = label.getWidth();
// Find out how much the font can grow in width.
double widthRatio = (double)componentWidth / (double)stringWidth;
int newFontSize = (int)(labelFont.getSize() * widthRatio);
int componentHeight = label.getHeight();
// Pick a new font size so it will not be larger than the height of label.
int fontSizeToUse = Math.min(newFontSize, componentHeight);
// Set the label's font size to the newly determined size.
label.setFont(new Font(labelFont.getName(), Font.PLAIN, fontSizeToUse));
Basically, the code looks at how much space the text in the `JLabel` takes up by using the `FontMetrics` object, and then uses that information to determine the largest font size that can be used without overflowing the text from the `JLabel`.
The above code can be inserted into perhaps the `paint` method of the `JFrame` which holds the `JLabel`, or some method which will be invoked when the font size needs to be changed.
The following is an screenshot of the above code in action:
(source: coobird.net)
Problem
I have a `JLabel` in a Container. The defaut size of the font is very small. I would like that the text of the `JLabel` to take the maximum size. How can I do that?