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      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.Paint;
     20 import android.graphics.Typeface;
     21 import android.os.Parcel;
     22 import android.text.ParcelableSpan;
     23 import android.text.TextPaint;
     24 import 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  */
     34 public 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