Java (AWT): fitting text in a box

Question

I have an application that extends a Frame. Then, it'll display a few lines of text using:

Font f = new Font("Arial", Font.PLAIN, 10);
g.setFont(f);
g.drawString("Test|great Yes ^.", x, y + 10);

Now what happens is that the text doesn't fit in the box around. E.g. I'm expecting the text to fit in [x,y]-[x+width, y+10] (don't care about the width) but it falls somewhat below the y+10 line. Now for most characters ('T', 'e', etc.) this fits but '|' and 'g' don't! They go below the y+10-line. It seems you can't use: draw at y + characterHeight. But what does work?

To see what I mean, here's some sample code:

import java.awt.*;

public class test extends Frame
{
        public test()
        {
                /* retrieve max window size */
                GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
                GraphicsDevice[] gs = ge.getScreenDevices();
                GraphicsConfiguration [] gc = gs[0].getConfigurations();
                Rectangle r = gc[0].getBounds();
                setSize(r.width, r.height);
                setVisible(true);
        }

        public void paint(Graphics g)
        {
                final int windowWidth  = getSize().width;
                final int windowHeight = getSize().height;
                g.setColor(Color.BLUE);
                g.fillRect(0, 0, windowWidth, windowHeight);
                g.setColor(Color.WHITE);
                g.fillRect(0, 100, windowWidth, 110);
                int textHeight = 100;
                Font f = new Font("Arial", Font.PLAIN, textHeight);
                g.setFont(f);
                g.setColor(Color.BLACK);
                g.drawString("Test|great Yes ^.", 10, 100 + textHeight);
        }

        public void guiLoop()
        {
                for(;;) { try { Thread.sleep(1000); } catch(Exception e) { } }
        }

        public static void main(String [] args)
        {
                new test().guiLoop();
        }
}

I tried the following code as well:

public void paint(Graphics g)
{
        final int windowWidth  = getSize().width;
        final int windowHeight = getSize().height;
        g.setColor(Color.BLUE);
        g.fillRect(0, 0, windowWidth, windowHeight);
        g.setColor(Color.WHITE);
        g.fillRect(0, 100, windowWidth, 110);
        int textHeight = 100;

        String str = "Test|great Yes ^.";
        Font f = new Font("Arial", Font.PLAIN, textHeight);
        Rectangle2D boundingRectangle = f.getStringBounds(str, 0, str.length(), new FontRenderContext(null, false, false));
        f = f.deriveFont((float)(textHeight * (textHeight / boundingRectangle.getHeight())));
        boundingRectangle = f.getStringBounds(str, 0, str.length(), new FontRenderContext(null, false, false));
        g.drawString(str, 10, 100 + (int)boundingRectangle.getHeight());

        g.setFont(f);
        g.setColor(Color.BLACK);
        g.drawString(str, 10, 100 + textHeight);
}

This is somewhat better: the text is smaller so it might fit, but there's still the problem that the y-position is incorrect.

All help is appreciated!

Answer 1

What about using FontMetrics? You can obtain it from Graphics object with g.getFontMetrics().

Than you can retrieve max descent or ascent or directly height (using getHeight), so your implementation will be font-indipendent and it should work fine.. check documentation here!

EDIT (to explain comments): there is no a direct way to tell to a string to draw itself in a manner that can fit a box. You have to do it by yourself.. like start from a max font size and check if width fits the box, otherwise decrement size and try again. For height you should FIRST decide (or obtain) max font height, then you can set how many pixel should the box be.

Answer 2

I think I solved it somewhat:

boundingBoxHeight: height of box in which the text should fit yOffset where to start drawing the font

            Font f = new Font("Arial", Font.PLAIN, boundingBoxHeight);
            g.setFont(f);
            FontMetrics fm = g.getFontMetrics();
            double shrink = ((double)textHeight / (double)fm.getHeight());
            double newSize = (double)textHeight * shrink;
            double newAsc  = (double)fm.getAscent() * shrink;
            int yOffset = (int)newAsc - fm.getLeading();
            f = f.deriveFont((float)newSize);
            g.setFont(f);

            g.drawString(str, 10, 100 + yOffset);

There's quite a bit of whitespace above the text though.