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 TextUtils.STYLE_SPAN;
54    }
55
56    public int describeContents() {
57        return 0;
58    }
59
60    public void writeToParcel(Parcel dest, int flags) {
61        dest.writeInt(mStyle);
62    }
63
64	/**
65	 * Returns the style constant defined in {@link android.graphics.Typeface}.
66	 */
67	public int getStyle() {
68		return mStyle;
69	}
70
71	@Override
72    public void updateDrawState(TextPaint ds) {
73        apply(ds, mStyle);
74    }
75
76	@Override
77    public void updateMeasureState(TextPaint paint) {
78        apply(paint, mStyle);
79    }
80
81    private static void apply(Paint paint, int style) {
82        int oldStyle;
83
84        Typeface old = paint.getTypeface();
85        if (old == null) {
86            oldStyle = 0;
87        } else {
88            oldStyle = old.getStyle();
89        }
90
91        int want = oldStyle | style;
92
93        Typeface tf;
94        if (old == null) {
95            tf = Typeface.defaultFromStyle(want);
96        } else {
97            tf = Typeface.create(old, want);
98        }
99
100        int fake = want & ~tf.getStyle();
101
102        if ((fake & Typeface.BOLD) != 0) {
103            paint.setFakeBoldText(true);
104        }
105
106        if ((fake & Typeface.ITALIC) != 0) {
107            paint.setTextSkewX(-0.25f);
108        }
109
110        paint.setTypeface(tf);
111    }
112}
113