Position line in graphic + java

Question

I am trying to write an integer inside a graphic shape and want it to always be in the center.

Is there any way to do this?

I am currently writing this not well:

Font font = new Font("Arial", Font.BOLD, 20); g.setFont(font); g.setColor(this.color); g.fillOval(bx, by, b.width, b.height); g.setColor(Color.black); g.drawString("1", bx + b.width/2 , b.y+ b.height/2); 

where b is the rectangle.

Answer 1

You can use the FontMetrics class to determine the exact size of the row you want to display, and then subtract half its X and Y sizes from your center point and draw it there, for example:

  FontMetrics fm = g.getFontMetrics(); Rectangle2D rect = fm.getStringBounds("1", g); g.drawString("1", (int) (bx + b.width/2 - rect.getWidth()/2), (int) (by + b.height/2 + rect.getHeight()/2)); 

Answer 2

I think the above answer should be satisfactory, although not accurate. I'm not sure why, but the way it is. So, for example, I would focus any object / component on the panel. But with strings it is not so simple. This probably has something to do with the upward descent of the text, this is what I got from some code that I found on the network a long time ago.

The code is below. It shows a very simple example showing how it works in comparison with the above solution, you just need to comment / not comment on the corresponding code, run the program once for each option and compare / see.

I must admit that I am not the author of the algorithm (unfortunately, I do not remember his / her name - thanks for the code and good work), although I implemented methods that allow additional bias for x and y.

 import java.awt.Color; import java.awt.FontMetrics; import java.awt.Graphics; import java.awt.HeadlessException; import java.awt.geom.Rectangle2D; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.SwingUtilities; public final class StringPainter { private StringPainter() { } public static void drawCenteredString(String s, int w, int h, Graphics g) { drawCenteredString(s, 0, 0, w, h, g); } public static void drawCenteredString(String s, int offsetX, int offsetY, int w, int h, Graphics g) { FontMetrics fm = g.getFontMetrics(); int x = (w - fm.stringWidth(s)) / 2 + offsetX; int y = (fm.getAscent() + (h - (fm.getAscent() + fm.getDescent())) / 2) + offsetY; g.drawString(s, x, y); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { createGUI(); } }); } private static void createGUI() throws HeadlessException { JPanel p = new JPanel() { private static final long serialVersionUID = 1L; @Override protected void paintComponent(Graphics g) { super.paintComponent(g); String str = "TEST"; // StringPainter.drawCenteredString(str, 0, 0, getWidth(), getHeight(), g); FontMetrics fm = g.getFontMetrics(); Rectangle2D rect = fm.getStringBounds(str, g); g.drawString(str, (int) (getX() + getWidth() / 2 - rect.getWidth() / 2), (int) (getY() + getHeight() / 2 + rect.getHeight() / 2)); g.setColor(Color.GREEN); g.fillOval(getWidth() / 2 - 2, getHeight() / 2 - 2, 4, 4); } }; JFrame f = new JFrame(); f.setContentPane(p); f.setSize(800, 600); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setVisible(true); } } 

Hope this helps.

Enjoy Java, Boro.