1 /* 2 * Copyright (C) 2024 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.ColorInt; 20 import android.annotation.Nullable; 21 import android.graphics.Color; 22 import android.text.style.CharacterStyle; 23 24 /** 25 * Finds the foreground text color for the given Spanned text so you can iterate through each color 26 * change. 27 * 28 * @hide 29 */ 30 @android.ravenwood.annotation.RavenwoodKeepWholeClass 31 public class SpanColors { 32 public static final @ColorInt int NO_COLOR_FOUND = Color.TRANSPARENT; 33 34 private final SpanSet<CharacterStyle> mCharacterStyleSpanSet = 35 new SpanSet<>(CharacterStyle.class); 36 @Nullable private TextPaint mWorkPaint; 37 SpanColors()38 public SpanColors() {} 39 40 /** 41 * Init for the given text 42 * 43 * @param workPaint A temporary TextPaint object that will be used to calculate the colors. The 44 * paint properties will be mutated on calls to {@link #getColorAt(int)} so 45 * make sure to reset it before you use it for something else. 46 * @param spanned the text to examine 47 * @param start index to start at 48 * @param end index of the end 49 */ init(TextPaint workPaint, Spanned spanned, int start, int end)50 public void init(TextPaint workPaint, Spanned spanned, int start, int end) { 51 mWorkPaint = workPaint; 52 mCharacterStyleSpanSet.init(spanned, start, end); 53 } 54 55 /** 56 * Removes all internal references to the spans to avoid memory leaks. 57 */ recycle()58 public void recycle() { 59 mWorkPaint = null; 60 mCharacterStyleSpanSet.recycle(); 61 } 62 63 /** 64 * Calculates the foreground color of the text at the given character index. 65 * 66 * <p>You must call {@link #init(TextPaint, Spanned, int, int)} before calling this 67 */ getColorAt(int index)68 public @ColorInt int getColorAt(int index) { 69 var finalColor = NO_COLOR_FOUND; 70 // Reset the paint so if we get a CharacterStyle that doesn't actually specify color, 71 // (like UnderlineSpan), we still return no color found. 72 mWorkPaint.setColor(finalColor); 73 for (int k = 0; k < mCharacterStyleSpanSet.numberOfSpans; k++) { 74 if ((index >= mCharacterStyleSpanSet.spanStarts[k]) 75 && (index <= mCharacterStyleSpanSet.spanEnds[k])) { 76 final CharacterStyle span = mCharacterStyleSpanSet.spans[k]; 77 span.updateDrawState(mWorkPaint); 78 79 finalColor = calculateFinalColor(mWorkPaint); 80 } 81 } 82 return finalColor; 83 } 84 calculateFinalColor(TextPaint workPaint)85 private @ColorInt int calculateFinalColor(TextPaint workPaint) { 86 // TODO: can we figure out what the getColorFilter() will do? 87 // if so, we also need to reset colorFilter before the loop in getColorAt() 88 return workPaint.getColor(); 89 } 90 } 91