JDK-8293776 : Adds CSS 4 and 8 digits hex coded Color

src/java.desktop/share/classes/javax/swing/text/html/CSS.java

@@ -38,6 +38,7 @@
 import java.util.ArrayList;
 import java.util.Enumeration;
 import java.util.Hashtable;
+import java.util.Map;
 import java.util.Objects;
 
 import javax.swing.ImageIcon;
@@ -1354,41 +1355,52 @@ else if (str.length() < 2)
       return colorstr;
     }
 
-     /**
-      * Convert a "#FFFFFF" hex string to a Color.
-      * If the color specification is bad, an attempt
-      * will be made to fix it up.
-      */
-    static final Color hexToColor(String value) {
-        String digits;
-        int n = value.length();
-        if (value.startsWith("#")) {
-            digits = value.substring(1, Math.min(value.length(), 7));
-        } else {
-            digits = value;
-        }
-        // Some webpage passes 3 digit color code as in #fff which is
-        // decoded as #000FFF resulting in blue background.
-        // As per https://www.w3.org/TR/CSS1/#color-units,
-        // The three-digit RGB notation (#rgb) is converted into six-digit form
-        // (#rrggbb) by replicating digits, not by adding zeros.
-        // This makes sure that white (#ffffff) can be specified with the short notation
-        // (#fff) and removes any dependencies on the color depth of the display.
-        if (digits.length() == 3) {
-            final String r = digits.substring(0, 1);
-            final String g = digits.substring(1, 2);
-            final String b = digits.substring(2, 3);
-            digits = String.format("%s%s%s%s%s%s", r, r, g, g, b, b);
-        }
-        String hstr = "0x" + digits;
-        Color c;
-        try {
-            c = Color.decode(hstr);
-        } catch (NumberFormatException nfe) {
-            c = null;
+    /**
+     * Convert a "#FFF", "#FFFF", "#FFFFFF" or "#FFFFFFFF" hex string to a Color.
+     * If the color specification is bad, an attempt will be made to fix it up.
+     */
+    static final Color hexToColor(String digits) {
+        // CSS Color level 4 allows webpage passes 3, 4, 6 or 8 digit color codes.
+        //   - 3 digits #[R][G][B] ........ represents #[RR][GG][BB]FF
+        //   - 4 digits #[R][G][B][A] ..... represents #[RR][GG][BB][AA]
+        //   - 6 digits #[RR][GG][BB] ..... represents #[RR][GG][BB]FF
+        //   - 8 digits #[RR][GG][BB][AA] . represents #[RR][GG][BB][AA]
+        final byte[] iseq = digits.startsWith("#") ?
+                                 iseqmap.get(Integer.valueOf(digits.length())):
+                                 iseqmap.get(Integer.valueOf(-digits.length()));
+        if (iseq == null) {
+            // Rejects string argument with a wrong number length.
+            return null;
         }
-         return c;
-     }
+        // Only 3, 4, 6 and 8 digits notations.
+        // Parses the string argument and build color value.
+        int dv;
+        int value = 0;
+        for (byte i : iseq) {
+            dv = i == -15 ? 15 : Character.digit(digits.charAt(i), 16);
+            if (dv < 0) {
+                // Rejects string argument with at least a non digit Character.
+                return null;
+            }
+            value = dv | value << 4;
+        }
+        return new Color(value, true);
+    }
+
+    // Map of Index Sequences. Index -15 means, use the default value 15.
+    private static final Map<Integer, byte[]> iseqmap =
+        Map.ofEntries(
+            // Positive key, for # prefixed string, is associated with index from 1 to 8.
+            // Negative key, for not # prefixed string, is associated with index from 0 to 7.
+            Map.entry(Integer.valueOf(4), new byte[]{-15, -15, 1, 1, 2, 2, 3, 3}),
+            Map.entry(Integer.valueOf(5), new byte[]{4, 4, 1, 1, 2, 2, 3, 3}),
+            Map.entry(Integer.valueOf(7), new byte[]{-15, -15, 1, 2, 3, 4, 5, 6}),
+            Map.entry(Integer.valueOf(9), new byte[]{7, 8, 1, 2, 3, 4, 6, 6}),
+            Map.entry(Integer.valueOf(-3), new byte[]{-15, -15, 0, 0, 1, 1, 2, 2}),
+            Map.entry(Integer.valueOf(-4), new byte[]{3, 3, 0, 0, 1, 1, 2, 2}),
+            Map.entry(Integer.valueOf(-6), new byte[]{-15, -15, 0, 1, 2, 3, 4, 5}),
+            Map.entry(Integer.valueOf(-8), new byte[]{6, 7, 0, 1, 2, 3, 4, 5})
+        );
 
     /**
      * Convert a color string such as "RED" or "#NNNNNN" or "rgb(r, g, b)"
@@ -3770,4 +3782,4 @@ private StyleSheet getStyleSheet(StyleSheet ss) {
     private transient StyleSheet styleSheet = null;
 
     static int baseFontSizeIndex = 3;
-}
+}

test/jdk/javax/swing/text/html/CSS/Hex3468DigitsColor.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2023, 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 8293776
+ * @summary Adds CSS 4 and 8 digits hex coded Color
+ * @run main Hex3468DigitsColor
+ */
+
+import java.awt.Color;
+import javax.swing.text.html.StyleSheet;
+
+public class Hex3468DigitsColor {
+
+    public static void main(String[] args) {
+        StringBuilder result = new StringBuilder();
+        boolean passed = true;
+        StyleSheet styleSheet = new StyleSheet();
+
+        // #rgba should be interpreted as #rrggbbaa according CSS Color Level 4.
+        // Then expecting 0xaaff1122 from Color.
+        Color color = styleSheet.stringToColor("#f12a");
+
+        if (0xaaff1122 != color.getRGB()) {
+            result.append("  Test for #f12a");
+            passed = false;
+        }
+
+        // In #rrggbbaa, last two digits should be interpreted as Alpha value according CSS Color Level 4.
+        // Then expecting 0xaaff1122 from Color.
+        color = styleSheet.stringToColor("#ff1122aa");
+
+        if (0xaaff1122 != color.getRGB()) {
+            result.append("  Test for #ff1122aa");
+            passed = false;
+        }
+
+        if (!passed) {
+            result.insert(0, " Failed :");
+            throw new RuntimeException(result.toString());
+        }
+    }
+}