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问题:
I am new to Java and trying to use Java2D Graphics to create a Image. But the output is coming as anti-aliased. I tried many ways to rectify it but doesn't work. The characters are getting distorted or jagged.
public BufferedImage createNameOnButton(String label) { int messageWidth = 0; Font font = new Font("Arial", Font.PLAIN, 11); BufferedImage bi = new BufferedImage( 10, 10, BufferedImage.TYPE_INT_RGB); Graphics2D g2d = (Graphics2D) bi.getGraphics(); g2d.setRenderingHint( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); g2d.setRenderingHint( RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON); g2d.setRenderingHint( RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON); g2d.setFont(font); bi = g2d.getDeviceConfiguration() .createCompatibleImage(500, 30, Transparency.BITMASK); FontMetrics fm = bi.getGraphics().getFontMetrics(font); int messageHeight = fm.getHeight() - fm.getDescent(); for (char ch : label.toCharArray()) { messageWidth += fm.charWidth(ch); } bi = bi.getSubimage(50, 0, messageWidth + 10, fm.getHeight()); Graphics g = bi.getGraphics(); g.setColor(Color.black); AttributedString as = new AttributedString(label); as.addAttribute(TextAttribute.FONT, font); g.drawString(as.getIterator(), 5, messageHeight); g2d.dispose(); g.dispose(); return bi; }
Can anyone please help me to rectify the error?
回答1:
Assuming you actually want smooth (non-aliased) text, TextLayout may make this easier. The FontRenderContext constructor can manage the anti-aliasing and fractional metrics settings.
Addendum: Using g2d.setColor(Color.blue) seems to produce the expected effect.
Addendum: On Mac OS X, the Pixie application in /Developer/Applications/Graphics Tools/ is convenient for examining the anti-alias pixels. On other platforms, Zoom may be used.
/** @see https://stackoverflow.com/questions/4285464 */ public class BITest extends JPanel { private BufferedImage image = createNameOnButton("Sample"); public BITest() { this.setPreferredSize(new Dimension( image.getWidth(), image.getHeight())); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); g.drawImage(image, 0, 0, null); } public BufferedImage createNameOnButton(String label) { Font font = new Font("Arial", Font.PLAIN, 64); FontRenderContext frc = new FontRenderContext(null, true, true); TextLayout layout = new TextLayout(label, font, frc); Rectangle r = layout.getPixelBounds(null, 0, 0); System.out.println(r); BufferedImage bi = new BufferedImage( r.width + 1, r.height + 1, BufferedImage.TYPE_INT_ARGB); Graphics2D g2d = (Graphics2D) bi.getGraphics(); g2d.setColor(Color.blue); layout.draw(g2d, 0, -r.y); g2d.dispose(); return bi; } private void display() { JFrame f = new JFrame("BITest"); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setUndecorated(true); f.add(this); f.pack(); f.setLocationRelativeTo(null); f.setVisible(true); } public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { @Override public void run() { new BITest().display(); } }); } }
回答2:
As Traroth mentioned it is more than likely due to
g2d.setRenderingHint( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); g2d.setRenderingHint( RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
Instead this should be
g2d.setRenderingHint( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_OFF); g2d.setRenderingHint( RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_OFF);
回答3:
I found that just this line does the trick:
g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
After that, just use drawString().
