Character spacing loop going infinitely

Character spacing loop going infinitely

I'm trying to figure out the right spacing for a iText chunk so it would
best fit an area of a certain width.
This is the code I'm using:
int width = someWidth;
Chunk chunk = new Chunk(string);
float chunkWidth;
float characterSpacing = -1f;
do
{
chunk.setCharacterSpacing(characterSpacing);
chunkWidth = chunk.getWidthPoint();
System.out.println(characterSpacing + " " + chunkWidth + " " +
width*0.75);
characterSpacing += 0.1f;
}
while (chunkWidth <= width*0.75);
However, this goes into an infinite loop because chunkWidth is not
changing. How do I fix it?