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      1 /*
      2  * Copyright (C) 2014 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;
     18 
     19 import android.annotation.NonNull;
     20 
     21 // Based on the native implementation of Primitive in
     22 // frameworks/base/core/jni/android_text_StaticLayout.cpp revision b808260
     23 public class Primitive {
     24     public final @NonNull PrimitiveType type;
     25     public final int location;
     26     // The following fields don't make sense for all types.
     27     // Box and Glue have width only.
     28     // Penalty has both width and penalty.
     29     // Word_break has penalty only.
     30     public final float width;
     31     public final float penalty;
     32 
     33     /**
     34      * Use {@code PrimitiveType#getNewPrimitive()}
     35      */
     36     private Primitive(@NonNull PrimitiveType type, int location, float width, float penalty) {
     37         this.type = type;
     38         this.location = location;
     39         this.width = width;
     40         this.penalty = penalty;
     41     }
     42 
     43     public static enum PrimitiveType {
     44         /**
     45          * Something with a constant width that is to be typeset - like a character.
     46          */
     47         BOX,
     48         /**
     49          * Blank space with fixed width.
     50          */
     51         GLUE,
     52         /**
     53          * Aesthetic cost indicating how desirable breaking at this point will be. A penalty of
     54          * {@link #PENALTY_INFINITY} means a forced non-break, whereas a penalty of negative
     55          * {@code #PENALTY_INFINITY} means a forced break.
     56          * <p/>
     57          * Currently, it only stores penalty with values 0 or -infinity.
     58          */
     59         PENALTY,
     60         /**
     61          * For tabs - variable width space.
     62          */
     63         VARIABLE,
     64         /**
     65          * Possible breakpoints within a word. Think of this as a high cost {@link #PENALTY}.
     66          */
     67         WORD_BREAK;
     68 
     69         public Primitive getNewPrimitive(int location) {
     70             assert this == VARIABLE;
     71             return new Primitive(this, location, 0f, 0f);
     72         }
     73 
     74         public Primitive getNewPrimitive(int location, float value) {
     75             assert this == BOX || this == GLUE || this == WORD_BREAK;
     76             if (this == BOX || this == GLUE) {
     77                 return new Primitive(this, location, value, 0f);
     78             } else {
     79                 return new Primitive(this, location, 0f, value);
     80             }
     81         }
     82 
     83         public Primitive getNewPrimitive(int location, float width, float penalty) {
     84             assert this == PENALTY;
     85             return new Primitive(this, location, width, penalty);
     86         }
     87 
     88         // forced non-break, negative infinity is forced break.
     89         public static final float PENALTY_INFINITY = 1e7f;
     90     }
     91 }
     92 
     93