import javax.swing.*; import java.awt.*; import java.awt.font.*; import java.awt.geom.*; public class SizeDisplayer extends JComponent { private Icon icon; private String text; private int xTextPad = 5; private int yTextPad = 5; //Reuse textSizeD and textSizeR to avoid creating //lots of unnecessary Dimensions and Rectangles. private Rectangle textSizeR = new Rectangle(); private Dimension textSizeD = new Dimension(); private Dimension userPreferredSize, //null userMinimumSize, //null userMaximumSize; //null public SizeDisplayer(String text, Icon icon) { this.text = text; this.icon = icon; setOpaque(true); } protected void paintComponent(Graphics g) { Graphics2D g2d = (Graphics2D)g.create(); //copy g Dimension minSize = getMinimumSize(); Dimension prefSize = getPreferredSize(); Dimension size = getSize(); int prefX = 0, prefY = 0; //Set hints so text looks nice. g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY); //Draw the maximum size rectangle if we're opaque. if (isOpaque()) { g2d.setColor(getBackground()); g2d.fillRect(0, 0, size.width, size.height); } //Draw the icon. if (icon != null) { Composite oldComposite = g2d.getComposite(); g2d.setComposite(AlphaComposite.getInstance( AlphaComposite.SRC_OVER, 0.1f)); icon.paintIcon(this, g2d, (size.width - icon.getIconWidth())/2, (size.height - icon.getIconHeight())/2); g2d.setComposite(oldComposite); } //Draw the preferred size rectangle. prefX = (size.width - prefSize.width)/2; prefY = (size.height - prefSize.height)/2; g2d.setColor(Color.RED); g2d.drawRect(prefX, prefY, prefSize.width - 1, prefSize.height - 1); //Draw the minimum size rectangle. if (minSize.width != prefSize.width || minSize.height != prefSize.height) { int minX = (size.width - minSize.width)/2; int minY = (size.height - minSize.height)/2; g2d.setColor(Color.CYAN); g2d.drawRect(minX, minY, minSize.width - 1, minSize.height - 1); } //Draw the text. if (text != null) { Dimension textSize = getTextSize(g2d); g2d.setColor(getForeground()); g2d.drawString(text, (size.width - textSize.width)/2, (size.height - textSize.height)/2 + g2d.getFontMetrics().getAscent()); } g2d.dispose(); } private Dimension getTextSize(Graphics2D g2d) { if (text == null) { textSizeD.setSize(0,0); } else { FontRenderContext frc; if (g2d != null) { frc = g2d.getFontRenderContext(); } else { frc = new FontRenderContext(null, false, false); } Rectangle2D textRect = getFont().getStringBounds( text, frc); textSizeR.setRect(textRect); textSizeD.setSize(textSizeR.width, textSizeR.height); } return textSizeD; } public Dimension getMinimumSize() { if (userMinimumSize != null) { //user has set the min size return userMinimumSize; } else { return getPreferredSize(); } } public Dimension getPreferredSize() { if (userPreferredSize != null) { //user has set the pref size return userPreferredSize; } else { return calculatePreferredSize(); } } public Dimension getMaximumSize() { if (userMaximumSize != null) { //user has set the max size return userMaximumSize; } else { return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE); } } public void setMinimumSize(Dimension newSize) { userMinimumSize = newSize; } public void setPreferredSize(Dimension newSize) { userPreferredSize = newSize; } public void setMaximumSize(Dimension newSize) { userMaximumSize = newSize; } private Dimension calculatePreferredSize() { Insets insets = getInsets(); Dimension textSize = getTextSize(null); int iconWidth = 0; int iconHeight = 0; if (icon != null) { iconWidth = icon.getIconWidth(); iconHeight = icon.getIconHeight(); } return new Dimension( Math.max(iconWidth, textSize.width + 2*xTextPad) + insets.left + insets.right, Math.max(iconHeight, textSize.height + 2*yTextPad) + insets.top + insets.bottom); } }