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/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.text.style;
import android.annotation.NonNull;
import android.text.TextPaint;
/**
* The classes that affect character-level text formatting in a way that
* changes the width or height of characters extend this class.
*/
public abstract class MetricAffectingSpan
extends CharacterStyle
implements UpdateLayout {
/**
* Classes that extend MetricAffectingSpan implement this method to update the text formatting
* in a way that can change the width or height of characters.
*
* @param textPaint the paint used for drawing the text
*/
public abstract void updateMeasureState(@NonNull TextPaint textPaint);
/**
* Returns "this" for most MetricAffectingSpans, but for
* MetricAffectingSpans that were generated by {@link #wrap},
* returns the underlying MetricAffectingSpan.
*/
@Override
public MetricAffectingSpan getUnderlying() {
return this;
}
/**
* A Passthrough MetricAffectingSpan is one that
* passes {@link #updateDrawState} and {@link #updateMeasureState}
* calls through to the specified MetricAffectingSpan
* while still being a distinct object,
* and is therefore able to be attached to the same Spannable
* to which the specified MetricAffectingSpan is already attached.
*/
/* package */ static class Passthrough extends MetricAffectingSpan {
private MetricAffectingSpan mStyle;
/**
* Creates a new Passthrough of the specfied MetricAffectingSpan.
*/
Passthrough(@NonNull MetricAffectingSpan cs) {
mStyle = cs;
}
/**
* Passes updateDrawState through to the underlying MetricAffectingSpan.
*/
@Override
public void updateDrawState(@NonNull TextPaint tp) {
mStyle.updateDrawState(tp);
}
/**
* Passes updateMeasureState through to the underlying MetricAffectingSpan.
*/
@Override
public void updateMeasureState(@NonNull TextPaint tp) {
mStyle.updateMeasureState(tp);
}
/**
* Returns the MetricAffectingSpan underlying this one, or the one
* underlying it if it too is a Passthrough.
*/
@Override
public MetricAffectingSpan getUnderlying() {
return mStyle.getUnderlying();
}
}
}
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