jdk/src/share/classes/sun/font/Underline.java
changeset 2 90ce3da70b43
child 1725 3be564c67d63
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/sun/font/Underline.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,306 @@
+/*
+ * Copyright 1998-2006 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+/*
+ *
+ * (C) Copyright IBM Corp. 1998, All Rights Reserved
+ */
+
+package sun.font;
+
+import java.awt.BasicStroke;
+import java.awt.Graphics2D;
+import java.awt.Shape;
+import java.awt.Stroke;
+
+import java.awt.geom.GeneralPath;
+import java.awt.geom.Line2D;
+
+import java.awt.font.TextAttribute;
+
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * This class provides drawing and bounds-measurement of
+ * underlines.  Additionally, it has a factory method for
+ * obtaining underlines from values of underline attributes.
+ */
+
+abstract class Underline {
+
+    /**
+     * Draws the underline into g2d.  The thickness should be obtained
+     * from a LineMetrics object.  Note that some underlines ignore the
+     * thickness parameter.
+     * The underline is drawn from (x1, y) to (x2, y).
+     */
+    abstract void drawUnderline(Graphics2D g2d,
+                                float thickness,
+                                float x1,
+                                float x2,
+                                float y);
+
+    /**
+     * Returns the bottom of the bounding rectangle for this underline.
+     */
+    abstract float getLowerDrawLimit(float thickness);
+
+    /**
+     * Returns a Shape representing the underline.  The thickness should be obtained
+     * from a LineMetrics object.  Note that some underlines ignore the
+     * thickness parameter.
+     */
+    abstract Shape getUnderlineShape(float thickness,
+                                     float x1,
+                                     float x2,
+                                     float y);
+
+     // Implementation of underline for standard and Input Method underlines.
+     // These classes are private.
+
+    // IM Underlines ignore thickness param, and instead use
+    // DEFAULT_THICKNESS
+    private static final float DEFAULT_THICKNESS = 1.0f;
+
+    // StandardUnderline's constructor takes a boolean param indicating
+    // whether to override the default thickness.  These values clarify
+    // the semantics of the parameter.
+    private static final boolean USE_THICKNESS = true;
+    private static final boolean IGNORE_THICKNESS = false;
+
+    // Implementation of standard underline and all input method underlines
+    // except UNDERLINE_LOW_GRAY.
+    private static final class StandardUnderline extends Underline {
+
+        // the amount by which to move the underline
+        private float shift;
+
+        // the actual line thickness is this value times
+        // the requested thickness
+        private float thicknessMultiplier;
+
+        // if non-null, underline is drawn with a BasicStroke
+        // with this dash pattern
+        private float[] dashPattern;
+
+        // if false, all underlines are DEFAULT_THICKNESS thick
+        // if true, use thickness param
+        private boolean useThickness;
+
+        // cached BasicStroke
+        private BasicStroke cachedStroke;
+
+        StandardUnderline(float shift,
+                          float thicknessMultiplier,
+                          float[] dashPattern,
+                          boolean useThickness) {
+
+            this.shift = shift;
+            this.thicknessMultiplier = thicknessMultiplier;
+            this.dashPattern = dashPattern;
+            this.useThickness = useThickness;
+            this.cachedStroke = null;
+        }
+
+        private BasicStroke createStroke(float lineThickness) {
+
+            if (dashPattern == null) {
+                return new BasicStroke(lineThickness);
+            }
+            else {
+                return new BasicStroke(lineThickness,
+                                       BasicStroke.CAP_BUTT,
+                                       BasicStroke.JOIN_MITER,
+                                       10.0f,
+                                       dashPattern,
+                                       0);
+            }
+        }
+
+        private float getLineThickness(float thickness) {
+
+            if (useThickness) {
+                return thickness * thicknessMultiplier;
+            }
+            else {
+                return DEFAULT_THICKNESS * thicknessMultiplier;
+            }
+        }
+
+        private Stroke getStroke(float thickness) {
+
+            float lineThickness = getLineThickness(thickness);
+            BasicStroke stroke = cachedStroke;
+            if (stroke == null ||
+                    stroke.getLineWidth() != lineThickness) {
+
+                stroke = createStroke(lineThickness);
+                cachedStroke = stroke;
+            }
+
+            return stroke;
+        }
+
+        void drawUnderline(Graphics2D g2d,
+                           float thickness,
+                           float x1,
+                           float x2,
+                           float y) {
+
+
+            Stroke saveStroke = g2d.getStroke();
+            g2d.setStroke(getStroke(thickness));
+            g2d.draw(new Line2D.Float(x1, y + shift, x2, y + shift));
+            g2d.setStroke(saveStroke);
+        }
+
+        float getLowerDrawLimit(float thickness) {
+
+            return shift + getLineThickness(thickness);
+        }
+
+        Shape getUnderlineShape(float thickness,
+                                float x1,
+                                float x2,
+                                float y) {
+
+            Stroke ulStroke = getStroke(thickness);
+            Line2D line = new Line2D.Float(x1, y + shift, x2, y + shift);
+            return ulStroke.createStrokedShape(line);
+        }
+    }
+
+    // Implementation of UNDERLINE_LOW_GRAY.
+    private static class IMGrayUnderline extends Underline {
+
+        private BasicStroke stroke;
+
+        IMGrayUnderline() {
+            stroke = new BasicStroke(DEFAULT_THICKNESS,
+                                     BasicStroke.CAP_BUTT,
+                                     BasicStroke.JOIN_MITER,
+                                     10.0f,
+                                     new float[] {1, 1},
+                                     0);
+        }
+
+        void drawUnderline(Graphics2D g2d,
+                           float thickness,
+                           float x1,
+                           float x2,
+                           float y) {
+
+            Stroke saveStroke = g2d.getStroke();
+            g2d.setStroke(stroke);
+
+            Line2D.Float drawLine = new Line2D.Float(x1, y, x2, y);
+            g2d.draw(drawLine);
+
+            drawLine.y1 += DEFAULT_THICKNESS;
+            drawLine.y2 += DEFAULT_THICKNESS;
+            drawLine.x1 += DEFAULT_THICKNESS;
+
+            g2d.draw(drawLine);
+
+            g2d.setStroke(saveStroke);
+        }
+
+        float getLowerDrawLimit(float thickness) {
+
+            return DEFAULT_THICKNESS * 2;
+        }
+
+        Shape getUnderlineShape(float thickness,
+                                float x1,
+                                float x2,
+                                float y) {
+
+            GeneralPath gp = new GeneralPath();
+
+            Line2D.Float line = new Line2D.Float(x1, y, x2, y);
+            gp.append(stroke.createStrokedShape(line), false);
+
+            line.y1 += DEFAULT_THICKNESS;
+            line.y2 += DEFAULT_THICKNESS;
+            line.x1 += DEFAULT_THICKNESS;
+
+            gp.append(stroke.createStrokedShape(line), false);
+
+            return gp;
+        }
+    }
+
+     // Keep a map of underlines, one for each type
+     // of underline.  The Underline objects are Flyweights
+     // (shared across multiple clients), so they should be immutable.
+     // If this implementation changes then clone underline
+     // instances in getUnderline before returning them.
+    private static final ConcurrentHashMap<Object, Underline>
+        UNDERLINES = new ConcurrentHashMap<Object, Underline>(6);
+    private static final Underline[] UNDERLINE_LIST;
+
+    static {
+        Underline[] uls = new Underline[6];
+
+        uls[0] = new StandardUnderline(0, 1, null, USE_THICKNESS);
+        UNDERLINES.put(TextAttribute.UNDERLINE_ON, uls[0]);
+
+        uls[1] = new StandardUnderline(1, 1, null, IGNORE_THICKNESS);
+        UNDERLINES.put(TextAttribute.UNDERLINE_LOW_ONE_PIXEL, uls[1]);
+
+        uls[2] = new StandardUnderline(1, 2, null, IGNORE_THICKNESS);
+        UNDERLINES.put(TextAttribute.UNDERLINE_LOW_TWO_PIXEL, uls[2]);
+
+        uls[3] = new StandardUnderline(1, 1, new float[] { 1, 1 }, IGNORE_THICKNESS);
+        UNDERLINES.put(TextAttribute.UNDERLINE_LOW_DOTTED, uls[3]);
+
+        uls[4] = new IMGrayUnderline();
+        UNDERLINES.put(TextAttribute.UNDERLINE_LOW_GRAY, uls[4]);
+
+        uls[5] = new StandardUnderline(1, 1, new float[] { 4, 4 }, IGNORE_THICKNESS);
+        UNDERLINES.put(TextAttribute.UNDERLINE_LOW_DASHED, uls[5]);
+
+        UNDERLINE_LIST = uls;
+    }
+
+    /**
+     * Return the Underline for the given value of
+     * TextAttribute.INPUT_METHOD_UNDERLINE or
+     * TextAttribute.UNDERLINE.
+     * If value is not an input method underline value or
+     * TextAttribute.UNDERLINE_ON, null is returned.
+     */
+    static Underline getUnderline(Object value) {
+
+        if (value == null) {
+            return null;
+        }
+
+        return (Underline) UNDERLINES.get(value);
+    }
+
+    static Underline getUnderline(int index) {
+        return index < 0 ? null : UNDERLINE_LIST[index];
+    }
+}