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.Canvas; 20 import android.graphics.Paint; 21 import android.os.Parcel; 22 import android.text.Layout; 23 import android.text.ParcelableSpan; 24 import android.text.TextUtils; 25 26 /** 27 * A paragraph style affecting the leading margin. There can be multiple leading 28 * margin spans on a single paragraph; they will be rendered in order, each 29 * adding its margin to the ones before it. The leading margin is on the right 30 * for lines in a right-to-left paragraph. 31 * <p> 32 * LeadingMarginSpans should be attached from the first character to the last 33 * character of a single paragraph. 34 */ 35 public interface LeadingMarginSpan 36 extends ParagraphStyle 37 { 38 /** 39 * Returns the amount by which to adjust the leading margin. Positive values 40 * move away from the leading edge of the paragraph, negative values move 41 * towards it. 42 * 43 * @param first true if the request is for the first line of a paragraph, 44 * false for subsequent lines 45 * @return the offset for the margin. 46 */ 47 public int getLeadingMargin(boolean first); 48 49 /** 50 * Renders the leading margin. This is called before the margin has been 51 * adjusted by the value returned by {@link #getLeadingMargin(boolean)}. 52 * 53 * @param c the canvas 54 * @param p the paint. The this should be left unchanged on exit. 55 * @param x the current position of the margin 56 * @param dir the base direction of the paragraph; if negative, the margin 57 * is to the right of the text, otherwise it is to the left. 58 * @param top the top of the line 59 * @param baseline the baseline of the line 60 * @param bottom the bottom of the line 61 * @param text the text 62 * @param start the start of the line 63 * @param end the end of the line 64 * @param first true if this is the first line of its paragraph 65 * @param layout the layout containing this line 66 */ 67 public void drawLeadingMargin(Canvas c, Paint p, 68 int x, int dir, 69 int top, int baseline, int bottom, 70 CharSequence text, int start, int end, 71 boolean first, Layout layout); 72 73 74 /** 75 * An extended version of {@link LeadingMarginSpan}, which allows the 76 * implementor to specify the number of lines of the paragraph to which 77 * this object is attached that the "first line of paragraph" margin width 78 * will be applied to. 79 * <p> 80 * There should only be one LeadingMarginSpan2 per paragraph. The leading 81 * margin line count affects all LeadingMarginSpans in the paragraph, 82 * adjusting the number of lines to which the first line margin is applied. 83 * <p> 84 * As with LeadingMarginSpans, LeadingMarginSpan2s should be attached from 85 * the beginning to the end of a paragraph. 86 */ 87 public interface LeadingMarginSpan2 extends LeadingMarginSpan, WrapTogetherSpan { 88 /** 89 * Returns the number of lines of the paragraph to which this object is 90 * attached that the "first line" margin will apply to. 91 */ 92 public int getLeadingMarginLineCount(); 93 }; 94 95 /** 96 * The standard implementation of LeadingMarginSpan, which adjusts the 97 * margin but does not do any rendering. 98 */ 99 public static class Standard implements LeadingMarginSpan, ParcelableSpan { 100 private final int mFirst, mRest; 101 102 /** 103 * Constructor taking separate indents for the first and subsequent 104 * lines. 105 * 106 * @param first the indent for the first line of the paragraph 107 * @param rest the indent for the remaining lines of the paragraph 108 */ 109 public Standard(int first, int rest) { 110 mFirst = first; 111 mRest = rest; 112 } 113 114 /** 115 * Constructor taking an indent for all lines. 116 * @param every the indent of each line 117 */ 118 public Standard(int every) { 119 this(every, every); 120 } 121 122 public Standard(Parcel src) { 123 mFirst = src.readInt(); 124 mRest = src.readInt(); 125 } 126 127 public int getSpanTypeId() { 128 return getSpanTypeIdInternal(); 129 } 130 131 /** @hide */ 132 public int getSpanTypeIdInternal() { 133 return TextUtils.LEADING_MARGIN_SPAN; 134 } 135 136 public int describeContents() { 137 return 0; 138 } 139 140 public void writeToParcel(Parcel dest, int flags) { 141 writeToParcelInternal(dest, flags); 142 } 143 144 /** @hide */ 145 public void writeToParcelInternal(Parcel dest, int flags) { 146 dest.writeInt(mFirst); 147 dest.writeInt(mRest); 148 } 149 150 public int getLeadingMargin(boolean first) { 151 return first ? mFirst : mRest; 152 } 153 154 public void drawLeadingMargin(Canvas c, Paint p, 155 int x, int dir, 156 int top, int baseline, int bottom, 157 CharSequence text, int start, int end, 158 boolean first, Layout layout) { 159 ; 160 } 161 } 162 } 163
