public PhysicalFont getSlotFont(int slot) {
/* This is essentially the runtime overhead for deferred font
* initialisation: a boolean test on obtaining a slot font,
* which will happen per slot, on initialisation of a strike
* (as that is the only frequent call site of this method.
*/
if (deferredInitialisation[slot]) {
doDeferredInitialisation(slot);
}
SunFontManager fm = SunFontManager.getInstance();
try {
PhysicalFont font = components[slot];
if (font == null) {
try {
font =
(PhysicalFont)
fm.findFont2D(componentNames[slot], style, FontManager.PHYSICAL_FALLBACK);
components[slot] = font;
} catch (ClassCastException cce) {
font = fm.getDefaultPhysicalFont();
}
}
return font;
} catch (Exception e) {
return fm.getDefaultPhysicalFont();
}
}
/* This is used for deferred initialisation, so that the components of
* a logical font are initialised only when the font is used.
* This can have a positive impact on start-up of most UI applications.
* Note that this technique cannot be used with a TTC font as it
* doesn't know which font in the collection is needed. The solution to
* this is that the initialisation checks if the returned font is
* really the one it wants by comparing the name against the name that
* was passed in (if none was passed in then you aren't using a TTC
* as you would have to specify the name in such a case).
* Assuming there's only two or three fonts in a collection then it
* may be sufficient to verify the returned name is the expected one.
* But half the time it won't be. However since initialisation of the
* TTC will initialise all its components then just do a findFont2D call
* to locate the right one.
* This code allows for initialisation of each slot on demand.
* There are two issues with this.
* 1) All metrics slots probably may be initialised anyway as many
* apps will query the overall font metrics. However this is not an
* absolute requirement
* 2) Some font configuration files on Solaris reference two versions
* of a TT font: a Latin-1 version, then a Pan-European version.
* One from /usr/openwin/lib/X11/fonts/TrueType, the other from
* a euro_fonts directory which is symlinked from numerous locations.
* This is difficult to avoid because the two do not share XLFDs so
* both will be consequently mapped by separate XLFDs needed by AWT.
* The difficulty this presents for lazy initialisation is that if
* all the components are not mapped at once, the smaller version may
* have been used only to be replaced later, and what is the consequence
* for a client that displayed the contents of this font already.
* After some thought I think this will not be a problem because when
* client tries to display a glyph only in the Euro font, the composite
* will ask all components of this font for that glyph and will get
* the euro one. Subsequent uses will all come from the 100% compatible
* euro one.
*/
private void doDeferredInitialisation(int slot) {
if (deferredInitialisation[slot] == false) {
return;
}
/* Synchronize on FontManager so that is the global lock
* to update its static set of deferred fonts.
* This global lock is rarely likely to be an issue as there
* are only going to be a few calls into this code.
*/
SunFontManager fm = SunFontManager.getInstance();
synchronized (fm) {
if (componentNames == null) {
componentNames = new String[numSlots];
}
if (components[slot] == null) {
/* Warning: it is possible that the returned component is
* not derived from the file name argument, this can happen if:
* - the file can't be found
* - the file has a bad font
* - the font in the file is superseded by a more complete one
* This should not be a problem for composite font as it will
* make no further use of this file, but code debuggers/
* maintainers need to be conscious of this possibility.
*/
if (componentFileNames != null && componentFileNames[slot] != null) {
components[slot] = fm.initialiseDeferredFont(componentFileNames[slot]);
}
if (components[slot] == null) {
components[slot] = fm.getDefaultPhysicalFont();
}
String name = components[slot].getFontName(null);
if (componentNames[slot] == null) {
componentNames[slot] = name;
} else if (!componentNames[slot].equalsIgnoreCase(name)) {
/* If a component specifies the file with a bad font,
* the corresponding slot will be initialized by
* default physical font. In such case findFont2D may
* return composite font which cannot be casted to
* physical font.
*/
try {
components[slot] =
(PhysicalFont)
fm.findFont2D(componentNames[slot], style, FontManager.PHYSICAL_FALLBACK);
} catch (ClassCastException cce) {
/* Assign default physical font to the slot */
components[slot] = fm.getDefaultPhysicalFont();
}
}
}
deferredInitialisation[slot] = false;
}
}
