1 /* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.text.style; 18 19 import android.graphics.Paint; 20 import android.text.TextPaint; 21 22 /** 23 * The classes that affect character-level text formatting in a way that 24 * changes the width or height of characters extend this class. 25 */ 26 public abstract class MetricAffectingSpan 27 extends CharacterStyle 28 implements UpdateLayout { 29 30 public abstract void updateMeasureState(TextPaint p); 31 32 /** 33 * Returns "this" for most MetricAffectingSpans, but for 34 * MetricAffectingSpans that were generated by {@link #wrap}, 35 * returns the underlying MetricAffectingSpan. 36 */ 37 @Override 38 public MetricAffectingSpan getUnderlying() { 39 return this; 40 } 41 42 /** 43 * A Passthrough MetricAffectingSpan is one that 44 * passes {@link #updateDrawState} and {@link #updateMeasureState} 45 * calls through to the specified MetricAffectingSpan 46 * while still being a distinct object, 47 * and is therefore able to be attached to the same Spannable 48 * to which the specified MetricAffectingSpan is already attached. 49 */ 50 /* package */ static class Passthrough extends MetricAffectingSpan { 51 private MetricAffectingSpan mStyle; 52 53 /** 54 * Creates a new Passthrough of the specfied MetricAffectingSpan. 55 */ 56 public Passthrough(MetricAffectingSpan cs) { 57 mStyle = cs; 58 } 59 60 /** 61 * Passes updateDrawState through to the underlying MetricAffectingSpan. 62 */ 63 @Override 64 public void updateDrawState(TextPaint tp) { 65 mStyle.updateDrawState(tp); 66 } 67 68 /** 69 * Passes updateMeasureState through to the underlying MetricAffectingSpan. 70 */ 71 @Override 72 public void updateMeasureState(TextPaint tp) { 73 mStyle.updateMeasureState(tp); 74 } 75 76 /** 77 * Returns the MetricAffectingSpan underlying this one, or the one 78 * underlying it if it too is a Passthrough. 79 */ 80 @Override 81 public MetricAffectingSpan getUnderlying() { 82 return mStyle.getUnderlying(); 83 } 84 } 85 } 86
