Parses a String containing a pango font description and returns
a Font object.
GraphicsEnvironment ge =
GraphicsEnvironment.getLocalGraphicsEnvironment();
GraphicsConfiguration gc =
ge.getDefaultScreenDevice().getDefaultConfiguration();
AffineTransform at = gc.getNormalizingTransform();
fontScale = at.getScaleY();
String family = "";
int style = Font.PLAIN;
int size = 10;
StringTokenizer tok = new StringTokenizer(pangoName);
while (tok.hasMoreTokens()) {
String word = tok.nextToken();
if (word.equalsIgnoreCase("italic")) {
style |= Font.ITALIC;
} else if (word.equalsIgnoreCase("bold")) {
style |= Font.BOLD;
} else if (CHARS_DIGITS.indexOf(word.charAt(0)) != -1) {
try {
size = Integer.parseInt(word);
} catch (NumberFormatException ex) {
}
} else {
if (family.length() > 0) {
family += " ";
}
family += word;
}
}
/*
* Java 2D font point sizes are in a user-space scale of 72dpi.
* GTK allows a user to configure a "dpi" property used to scale
* the fonts used to match a user's preference.
* To match the font size of GTK apps we need to obtain this DPI and
* adjust as follows:
* Some versions of GTK use XSETTINGS if available to dynamically
* monitor user-initiated changes in the DPI to be used by GTK
* apps. This value is also made available as the Xft.dpi X resource.
* This is presumably a function of the font preferences API and/or
* the manner in which it requests the toolkit to update the default
* for the desktop. This dual approach is probably necessary since
* other versions of GTK - or perhaps some apps - determine the size
* to use only at start-up from that X resource.
* If that resource is not set then GTK scales for the DPI resolution
* reported by the Xserver using the formula
* DisplayHeight(dpy, screen) / DisplayHeightMM(dpy, screen) * 25.4
* (25.4mm == 1 inch).
* JDK tracks the Xft.dpi XSETTINGS property directly so it can
* dynamically change font size by tracking just that value.
* If that resource is not available use the same fall back formula
* as GTK (see calculation for fontScale).
*
* GTK's default setting for Xft.dpi is 96 dpi (and it seems -1
* apparently also can mean that "default"). However this default
* isn't used if there's no property set. The real default in the
* absence of a resource is the Xserver reported dpi.
* Finally this DPI is used to calculate the nearest Java 2D font
* 72 dpi font size.
* There are cases in which JDK behaviour may not exactly mimic
* GTK native app behaviour :
* 1) When a GTK app is not able to dynamically track the changes
* (does not use XSETTINGS), JDK will resize but other apps will
* not. This is OK as JDK is exhibiting preferred behaviour and
* this is probably how all later GTK apps will behave
* 2) When a GTK app does not use XSETTINGS and for some reason
* the XRDB property is not present. JDK will pick up XSETTINGS
* and the GTK app will use the Xserver default. Since its
* impossible for JDK to know that some other GTK app is not
* using XSETTINGS its impossible to account for this and in any
* case for it to be a problem the values would have to be different.
* It also seems unlikely to arise except when a user explicitly
* deletes the X resource database entry.
* 3) Because of rounding errors sizes may differ very slightly
* between JDK and GTK. To fix that would at the very least require
* Swing to specify floating pt font sizes.
* Eg "10 pts" for GTK at 96 dpi to get the same size at Java 2D's
* 72 dpi you'd need to specify exactly 13.33.
* There also some other issues to be aware of for the future:
* GTK specifies the Xft.dpi value as server-wide which when used
* on systems with 2 distinct X screens with different physical DPI
* the font sizes will inevitably appear different. It would have
* been a more user-friendly design to further adjust that one
* setting depending on the screen resolution to achieve perceived
* equivalent sizes. If such a change were ever to be made in GTK
* we would need to update for that.
*/
double dsize = size;
int dpi = 96;
Object value =
Toolkit.getDefaultToolkit().getDesktopProperty("gnome.Xft/DPI");
if (value instanceof Integer) {
dpi = ((Integer)value).intValue() / 1024;
if (dpi == -1) {
dpi = 96;
}
if (dpi < 50) { /* 50 dpi is the minimum value gnome allows */
dpi = 50;
}
/* The Java rasteriser assumes pts are in a user space of
* 72 dpi, so we need to adjust for that.
*/
dsize = ((double)(dpi * size)/ 72.0);
} else {
/* If there's no property, GTK scales for the resolution
* reported by the Xserver using the formula listed above.
* fontScale already accounts for the 72 dpi Java 2D space.
*/
dsize = size * fontScale;
}
/* Round size to nearest integer pt size */
size = (int)(dsize + 0.5);
if (size < 1) {
size = 1;
}
String fcFamilyLC = family.toLowerCase();
if (FontManager.mapFcName(fcFamilyLC) != null) {
/* family is a Fc/Pango logical font which we need to expand. */
return FontManager.getFontConfigFUIR(fcFamilyLC, style, size);
} else {
/* It's a physical font which we will create with a fallback */
Font font = new FontUIResource(family, style, size);
return FontManager.getCompositeFontUIResource(font);
}
