StyleSpan.java revision a70d4a90a029910f788c3e7f8715cf3b842b1e2b 
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.Paint;
20import android.graphics.Typeface;
21import android.os.Parcel;
22import android.text.ParcelableSpan;
23import android.text.TextPaint;
24import android.text.TextUtils;
25
26/**
27 *
28 * Describes a style in a span.
29 * Note that styles are cumulative -- if both bold and italic are set in
30 * separate spans, or if the base style is bold and a span calls for italic,
31 * you get bold italic.  You can't turn off a style from the base style.
32 *
33 */
34public class StyleSpan extends MetricAffectingSpan implements ParcelableSpan {
35
36    private final int mStyle;
37
38    /**
39     *
40     * @param style An integer constant describing the style for this span. Examples
41     * include bold, italic, and normal. Values are constants defined
42     * in {@link android.graphics.Typeface}.
43     */
44    public StyleSpan(int style) {
45        mStyle = style;
46    }
47
48    public StyleSpan(Parcel src) {
49        mStyle = src.readInt();
50    }
51
52    public int getSpanTypeId() {
53        return getSpanTypeIdInternal();
54    }
55
56    /** @hide */
57    public int getSpanTypeIdInternal() {
58        return TextUtils.STYLE_SPAN;
59    }
60
61    public int describeContents() {
62        return 0;
63    }
64
65    public void writeToParcel(Parcel dest, int flags) {
66        writeToParcelInternal(dest, flags);
67    }
68
69    /** @hide */
70    public void writeToParcelInternal(Parcel dest, int flags) {
71        dest.writeInt(mStyle);
72    }
73
74    /**
75     * Returns the style constant defined in {@link android.graphics.Typeface}.
76     */
77    public int getStyle() {
78        return mStyle;
79    }
80
81    @Override
82    public void updateDrawState(TextPaint ds) {
83        apply(ds, mStyle);
84    }
85
86    @Override
87    public void updateMeasureState(TextPaint paint) {
88        apply(paint, mStyle);
89    }
90
91    private static void apply(Paint paint, int style) {
92        int oldStyle;
93
94        Typeface old = paint.getTypeface();
95        if (old == null) {
96            oldStyle = 0;
97        } else {
98            oldStyle = old.getStyle();
99        }
100
101        int want = oldStyle | style;
102
103        Typeface tf;
104        if (old == null) {
105            tf = Typeface.defaultFromStyle(want);
106        } else {
107            tf = Typeface.create(old, want);
108        }
109
110        int fake = want & ~tf.getStyle();
111
112        if ((fake & Typeface.BOLD) != 0) {
113            paint.setFakeBoldText(true);
114        }
115
116        if ((fake & Typeface.ITALIC) != 0) {
117            paint.setTextSkewX(-0.25f);
118        }
119
120        paint.setTypeface(tf);
121    }
122}
123