ReplacementSpan.java revision 4037d51b132a85dcfe37a95f9d2d91ad23d162fd 
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.annotation.IntRange;
20import android.annotation.NonNull;
21import android.annotation.Nullable;
22import android.graphics.Canvas;
23import android.graphics.Paint;
24import android.text.TextPaint;
25
26public abstract class ReplacementSpan extends MetricAffectingSpan {
27
28    /**
29     * Returns the width of the span. Extending classes can set the height of the span by updating
30     * attributes of {@link android.graphics.Paint.FontMetricsInt}. If the span covers the whole
31     * text, and the height is not set,
32     * {@link #draw(Canvas, CharSequence, int, int, float, int, int, int, Paint)} will not be
33     * called for the span.
34     *
35     * @param paint Paint instance.
36     * @param text Current text.
37     * @param start Start character index for span.
38     * @param end End character index for span.
39     * @param fm Font metrics, can be null.
40     * @return Width of the span.
41     */
42    public abstract int getSize(@NonNull Paint paint, CharSequence text,
43                        @IntRange(from = 0) int start, @IntRange(from = 0) int end,
44                        @Nullable Paint.FontMetricsInt fm);
45
46    /**
47     * Draws the span into the canvas.
48     *
49     * @param canvas Canvas into which the span should be rendered.
50     * @param text Current text.
51     * @param start Start character index for span.
52     * @param end End character index for span.
53     * @param x Edge of the replacement closest to the leading margin.
54     * @param top Top of the line.
55     * @param y Baseline.
56     * @param bottom Bottom of the line.
57     * @param paint Paint instance.
58     */
59    public abstract void draw(@NonNull Canvas canvas, CharSequence text,
60                              @IntRange(from = 0) int start, @IntRange(from = 0) int end, float x,
61                              int top, int y, int bottom, @NonNull Paint paint);
62
63    /**
64     * This method does nothing, since ReplacementSpans are measured
65     * explicitly instead of affecting Paint properties.
66     */
67    public void updateMeasureState(TextPaint p) { }
68
69    /**
70     * This method does nothing, since ReplacementSpans are drawn
71     * explicitly instead of affecting Paint properties.
72     */
73    public void updateDrawState(TextPaint ds) { }
74}
75