+ * {@code Font.textRequiresLayout(chars, 0, chars.length);}
+ *
+ * An application may find this information helpful in
+ * performance sensitive code.
+ * + * Note that even if this method returns {@code false}, layout processing + * may still be invoked when used with any {@code Font} + * for which {@link #hasLayoutAttributes()} returns {@code true}, + * so that method will need to be consulted for the specific font, + * in order to obtain an answer which accounts for such font attributes. + * + * @param chars the text. + * @param start the index of the first char to examine. + * @param end the ending index, exclusive. + * @return {@code true} if the specified text will need special layout. + * @throws NullPointerException if {@code chars} is null. + * @throws ArrayIndexOutOfBoundsException if {@code start} is negative or + * {@code end} is greater than the length of the {@code chars} array. + * @since 9 + */ + public static boolean textRequiresLayout(char[] chars, + int start, int end) { + if (chars == null) { + throw new NullPointerException("null char array"); + } + if (start < 0 || end > chars.length) { + throw new ArrayIndexOutOfBoundsException("start < 0 or end > len"); + } + return FontUtilities.isComplexScript(chars, start, end); + } + + /** * Returns a {@code Font} appropriate to the attributes. * If {@code attributes} contains a {@code FONT} attribute * with a valid {@code Font} as its value, it will be diff -r dcb7441b014d -r 5b36d70170d6 jdk/src/java.desktop/share/classes/sun/font/FontUtilities.java --- a/jdk/src/java.desktop/share/classes/sun/font/FontUtilities.java Tue Apr 05 21:13:44 2016 +0400 +++ b/jdk/src/java.desktop/share/classes/sun/font/FontUtilities.java Tue Apr 05 11:52:52 2016 -0700 @@ -183,6 +183,25 @@ } /** + * Return true if there any characters which would trigger layout. + * This method considers supplementary characters to be simple, + * since we do not presently invoke layout on any code points in + * outside the BMP. + */ + public static boolean isComplexScript(char [] chs, int start, int limit) { + + for (int i = start; i < limit; i++) { + if (chs[i] < MIN_LAYOUT_CHARCODE) { + continue; + } + else if (isComplexCharCode(chs[i])) { + return true; + } + } + return false; + } + + /** * If there is anything in the text which triggers a case * where char->glyph does not map 1:1 in straightforward * left->right ordering, then this method returns true. diff -r dcb7441b014d -r 5b36d70170d6 jdk/test/java/awt/FontClass/TextRequiresLayoutTest.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/jdk/test/java/awt/FontClass/TextRequiresLayoutTest.java Tue Apr 05 11:52:52 2016 -0700 @@ -0,0 +1,85 @@ +/* + * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ + +/* + * @test + * @bug 8146324 + * @summary Test Font.textRequiresLayout + */ + +import java.awt.Font; + +public class TextRequiresLayoutTest { + + public static void main(String args[]) { + + String simpleStr = "Hello World"; + String complexStr = "\u0641\u0642\u0643"; + char[] simpleChars = simpleStr.toCharArray(); + char[] complexChars = complexStr.toCharArray(); + + if (Font.textRequiresLayout(simpleChars, 0, simpleChars.length)) { + throw new RuntimeException("Simple text should not need layout"); + } + + if (!Font.textRequiresLayout(complexChars, 0, complexChars.length)) { + throw new RuntimeException("Complex text should need layout"); + } + + if (Font.textRequiresLayout(complexChars, 0, 0)) { + throw new RuntimeException("Empty text should not need layout"); + } + + boolean except = false; + try { + Font.textRequiresLayout(null, 0, 0); + } catch (NullPointerException npe) { + except = true; + } + if (!except) { + throw new RuntimeException("No expected IllegalArgumentException"); + } + + except = false; + try { + Font.textRequiresLayout(complexChars, -1, 0); + } catch (ArrayIndexOutOfBoundsException aioobe) { + except = true; + } + if (!except) { + throw new + RuntimeException("No expected ArrayIndexOutOfBoundsException"); + } + + except = false; + try { + Font.textRequiresLayout(complexChars, 0, complexChars.length+1); + } catch (ArrayIndexOutOfBoundsException aioobe) { + except = true; + } + if (!except) { + throw new + RuntimeException("No expected ArrayIndexOutOfBoundsException"); + } + } +}