I notice differences in font distribution using OpenJDK compared to OracleJDK. I narrowed it down to fonts. They are rendered by OpenJDK a little wider ... A careful visual inspection of the screenshot above shows that the width of the characters is the same, the only difference is the distance. I also confirmed this with programmatically checking font metrics for all A-Za-z0-9 characters.
eg. Line "Dialog - Normal" at 12pt
- 125 pixels in OpenJDK - my build 8u131-b11
- 125 pixels in OpenJDK - revolutions per second from redhat disk - 1.8u45-b13
- 120px on OracleJDK - 8u131-b11 release from Oracle website
, -Dawt.useSystemAAFontSettings, -Dswing.useSystemFontSettings, -Dswing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel Java_Runtime_Environment_fonts. , .
sun.font.FontScaler, fontscaler. sun.font.FontUtilities, -Dsun.java2d.font.scaler=t2k, .
: FreetypeFontScaler T2KFontScaler?
if (FontUtilities.isOpenJDK) {
scalerClass = Class.forName("sun.font.FreetypeFontScaler");
} else {
scalerClass = Class.forName("sun.font.T2KFontScaler");
}
,
public class FontTester {
public static void main(String[] args) throws Exception {
System.out.println(String.format("java.home=%s", System.getProperty("java.home")));
String family = Font.DIALOG;
int style = Font.PLAIN;
describeFont(new Font(family, style, 12));
JFrame frame = new JFrame();
frame.setSize(800, 600);
frame.add(new DemoPanel());
frame.setVisible(true);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
}
private static class DemoPanel extends JPanel {
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
String family = Font.DIALOG;
int style = Font.PLAIN;
Font font = new Font(family, style, 20);
g.setFont(font);
String str = family + " - " + name(font) + " ";
Rectangle2D bounds = g.getFontMetrics().getStringBounds(str, g);
str += String.format("%f x %f", bounds.getWidth(), bounds.getHeight());
g.drawString(str, 10, 50);
}
private String name(Font font) {
List<String> attrs = new ArrayList<>();
if (font.isBold()) {
attrs.add("bold");
}
if (font.isItalic()) {
attrs.add("italic");
}
if (font.isPlain()) {
attrs.add("plain");
}
return String.join(",", attrs);
}
}
private static void describeFont(Font font) throws Exception {
Method method = Font.class.getDeclaredMethod("getFont2D");
method.setAccessible(true);
Font2D font2d = (Font2D) method.invoke(font);
System.out.print(String.format("%s: ", font));
describeFont2D(font2d);
}
private static void describeFont2D(Font2D font) {
if (font instanceof CompositeFont) {
CompositeFont cf = (CompositeFont) font;
for (int i = 0; i < cf.getNumSlots(); i++) {
PhysicalFont pf = cf.getSlotFont(i);
describeFont2D(pf);
break;
}
} else {
System.out.print(String.format("-> %s \n", font));
}
}
}
, , sun.font.FontStrike.getGlyphMetrics(int) . - 39 ( "D" ) X 14.0px Oracle JDK ( T2KFontScaler), 15.0px OpenJDK ( FreetypeFontScaler)
, "", fontbox Java- , X Glyph-ID 39 HMTX TTF LiberationSans-Regular.ttf. - 1479 , 14.44px 20pt.
"i" - - 76. 4,44 fontbox 4 T2KScaler, FreetypeScaler
/, "" . , Oracle, Open JDK , , Oracle.
g2.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);