The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 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 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 19 | import android.text.TextPaint; |
| 20 | |
| 21 | /** |
| 22 | * The classes that affect character-level text formatting in a way that |
| 23 | * changes the width or height of characters extend this class. |
| 24 | */ |
| 25 | public abstract class MetricAffectingSpan |
| 26 | extends CharacterStyle |
| 27 | implements UpdateLayout { |
| 28 | |
| 29 | public abstract void updateMeasureState(TextPaint p); |
| 30 | |
| 31 | /** |
| 32 | * Returns "this" for most MetricAffectingSpans, but for |
| 33 | * MetricAffectingSpans that were generated by {@link #wrap}, |
| 34 | * returns the underlying MetricAffectingSpan. |
| 35 | */ |
| 36 | @Override |
| 37 | public MetricAffectingSpan getUnderlying() { |
| 38 | return this; |
| 39 | } |
| 40 | |
| 41 | /** |
| 42 | * A Passthrough MetricAffectingSpan is one that |
| 43 | * passes {@link #updateDrawState} and {@link #updateMeasureState} |
| 44 | * calls through to the specified MetricAffectingSpan |
| 45 | * while still being a distinct object, |
| 46 | * and is therefore able to be attached to the same Spannable |
| 47 | * to which the specified MetricAffectingSpan is already attached. |
| 48 | */ |
| 49 | /* package */ static class Passthrough extends MetricAffectingSpan { |
| 50 | private MetricAffectingSpan mStyle; |
| 51 | |
| 52 | /** |
| 53 | * Creates a new Passthrough of the specfied MetricAffectingSpan. |
| 54 | */ |
| 55 | public Passthrough(MetricAffectingSpan cs) { |
| 56 | mStyle = cs; |
| 57 | } |
| 58 | |
| 59 | /** |
| 60 | * Passes updateDrawState through to the underlying MetricAffectingSpan. |
| 61 | */ |
| 62 | @Override |
| 63 | public void updateDrawState(TextPaint tp) { |
| 64 | mStyle.updateDrawState(tp); |
| 65 | } |
| 66 | |
| 67 | /** |
| 68 | * Passes updateMeasureState through to the underlying MetricAffectingSpan. |
| 69 | */ |
| 70 | @Override |
| 71 | public void updateMeasureState(TextPaint tp) { |
| 72 | mStyle.updateMeasureState(tp); |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * Returns the MetricAffectingSpan underlying this one, or the one |
| 77 | * underlying it if it too is a Passthrough. |
| 78 | */ |
| 79 | @Override |
| 80 | public MetricAffectingSpan getUnderlying() { |
| 81 | return mStyle.getUnderlying(); |
| 82 | } |
| 83 | } |
| 84 | } |