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 | |
| 19 | import android.graphics.Canvas; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 20 | import android.graphics.Paint; |
| 21 | import android.graphics.Rect; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 22 | import android.graphics.drawable.Drawable; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 23 | |
| 24 | import java.lang.ref.WeakReference; |
| 25 | |
| 26 | /** |
| 27 | * |
| 28 | */ |
| 29 | public abstract class DynamicDrawableSpan extends ReplacementSpan { |
| 30 | private static final String TAG = "DynamicDrawableSpan"; |
| 31 | |
| 32 | /** |
| 33 | * A constant indicating that the bottom of this span should be aligned |
| 34 | * with the bottom of the surrounding text, i.e., at the same level as the |
| 35 | * lowest descender in the text. |
| 36 | */ |
| 37 | public static final int ALIGN_BOTTOM = 0; |
| 38 | |
| 39 | /** |
| 40 | * A constant indicating that the bottom of this span should be aligned |
| 41 | * with the baseline of the surrounding text. |
| 42 | */ |
| 43 | public static final int ALIGN_BASELINE = 1; |
| 44 | |
| 45 | protected final int mVerticalAlignment; |
| 46 | |
| 47 | public DynamicDrawableSpan() { |
| 48 | mVerticalAlignment = ALIGN_BOTTOM; |
| 49 | } |
| 50 | |
| 51 | /** |
| 52 | * @param verticalAlignment one of {@link #ALIGN_BOTTOM} or {@link #ALIGN_BASELINE}. |
| 53 | */ |
| 54 | protected DynamicDrawableSpan(int verticalAlignment) { |
| 55 | mVerticalAlignment = verticalAlignment; |
| 56 | } |
| 57 | |
| 58 | /** |
| 59 | * Returns the vertical alignment of this span, one of {@link #ALIGN_BOTTOM} or |
| 60 | * {@link #ALIGN_BASELINE}. |
| 61 | */ |
| 62 | public int getVerticalAlignment() { |
| 63 | return mVerticalAlignment; |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * Your subclass must implement this method to provide the bitmap |
| 68 | * to be drawn. The dimensions of the bitmap must be the same |
| 69 | * from each call to the next. |
| 70 | */ |
| 71 | public abstract Drawable getDrawable(); |
| 72 | |
| 73 | @Override |
| 74 | public int getSize(Paint paint, CharSequence text, |
| 75 | int start, int end, |
| 76 | Paint.FontMetricsInt fm) { |
| 77 | Drawable d = getCachedDrawable(); |
| 78 | Rect rect = d.getBounds(); |
| 79 | |
| 80 | if (fm != null) { |
| 81 | fm.ascent = -rect.bottom; |
| 82 | fm.descent = 0; |
| 83 | |
| 84 | fm.top = fm.ascent; |
| 85 | fm.bottom = 0; |
| 86 | } |
| 87 | |
| 88 | return rect.right; |
| 89 | } |
| 90 | |
| 91 | @Override |
| 92 | public void draw(Canvas canvas, CharSequence text, |
| 93 | int start, int end, float x, |
| 94 | int top, int y, int bottom, Paint paint) { |
| 95 | Drawable b = getCachedDrawable(); |
| 96 | canvas.save(); |
| 97 | |
| 98 | int transY = bottom - b.getBounds().bottom; |
| 99 | if (mVerticalAlignment == ALIGN_BASELINE) { |
| 100 | transY -= paint.getFontMetricsInt().descent; |
| 101 | } |
| 102 | |
| 103 | canvas.translate(x, transY); |
| 104 | b.draw(canvas); |
| 105 | canvas.restore(); |
| 106 | } |
| 107 | |
| 108 | private Drawable getCachedDrawable() { |
| 109 | WeakReference<Drawable> wr = mDrawableRef; |
| 110 | Drawable d = null; |
| 111 | |
| 112 | if (wr != null) |
| 113 | d = wr.get(); |
| 114 | |
| 115 | if (d == null) { |
| 116 | d = getDrawable(); |
| 117 | mDrawableRef = new WeakReference<Drawable>(d); |
| 118 | } |
| 119 | |
| 120 | return d; |
| 121 | } |
| 122 | |
| 123 | private WeakReference<Drawable> mDrawableRef; |
| 124 | } |
| 125 | |