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
17package android.text.style;
18
19import android.graphics.Canvas;
20import android.graphics.Color;
21import android.graphics.Paint;
22import android.graphics.Rect;
23import android.graphics.Paint.Style;
24import android.graphics.drawable.Drawable;
25import android.util.Log;
26
27import java.lang.ref.WeakReference;
28
29/**
30 *
31 */
32public abstract class DynamicDrawableSpan extends ReplacementSpan {
33    private static final String TAG = "DynamicDrawableSpan";
34
35    /**
36     * A constant indicating that the bottom of this span should be aligned
37     * with the bottom of the surrounding text, i.e., at the same level as the
38     * lowest descender in the text.
39     */
40    public static final int ALIGN_BOTTOM = 0;
41
42    /**
43     * A constant indicating that the bottom of this span should be aligned
44     * with the baseline of the surrounding text.
45     */
46    public static final int ALIGN_BASELINE = 1;
47
48    protected final int mVerticalAlignment;
49
50    public DynamicDrawableSpan() {
51        mVerticalAlignment = ALIGN_BOTTOM;
52    }
53
54    /**
55     * @param verticalAlignment one of {@link #ALIGN_BOTTOM} or {@link #ALIGN_BASELINE}.
56     */
57    protected DynamicDrawableSpan(int verticalAlignment) {
58        mVerticalAlignment = verticalAlignment;
59    }
60
61    /**
62     * Returns the vertical alignment of this span, one of {@link #ALIGN_BOTTOM} or
63     * {@link #ALIGN_BASELINE}.
64     */
65    public int getVerticalAlignment() {
66        return mVerticalAlignment;
67    }
68
69    /**
70     * Your subclass must implement this method to provide the bitmap
71     * to be drawn.  The dimensions of the bitmap must be the same
72     * from each call to the next.
73     */
74    public abstract Drawable getDrawable();
75
76    @Override
77    public int getSize(Paint paint, CharSequence text,
78                         int start, int end,
79                         Paint.FontMetricsInt fm) {
80        Drawable d = getCachedDrawable();
81        Rect rect = d.getBounds();
82
83        if (fm != null) {
84            fm.ascent = -rect.bottom;
85            fm.descent = 0;
86
87            fm.top = fm.ascent;
88            fm.bottom = 0;
89        }
90
91        return rect.right;
92    }
93
94    @Override
95    public void draw(Canvas canvas, CharSequence text,
96                     int start, int end, float x,
97                     int top, int y, int bottom, Paint paint) {
98        Drawable b = getCachedDrawable();
99        canvas.save();
100
101        int transY = bottom - b.getBounds().bottom;
102        if (mVerticalAlignment == ALIGN_BASELINE) {
103            transY -= paint.getFontMetricsInt().descent;
104        }
105
106        canvas.translate(x, transY);
107        b.draw(canvas);
108        canvas.restore();
109    }
110
111    private Drawable getCachedDrawable() {
112        WeakReference<Drawable> wr = mDrawableRef;
113        Drawable d = null;
114
115        if (wr != null)
116            d = wr.get();
117
118        if (d == null) {
119            d = getDrawable();
120            mDrawableRef = new WeakReference<Drawable>(d);
121        }
122
123        return d;
124    }
125
126    private WeakReference<Drawable> mDrawableRef;
127}
128
129