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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.ColorInt;
import android.annotation.NonNull;
import android.annotation.Px;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.Parcel;
import android.text.ParcelableSpan;
import android.text.TextUtils;
/**
* Used to change the background of lines where the span is attached to.
*/
public interface LineBackgroundSpan extends ParagraphStyle
{
/**
* Draw the background on the canvas.
*
* @param canvas canvas on which the span should be rendered
* @param paint paint used to draw text, which should be left unchanged on exit
* @param left left position of the line relative to input canvas, in pixels
* @param right right position of the line relative to input canvas, in pixels
* @param top top position of the line relative to input canvas, in pixels
* @param baseline baseline of the text relative to input canvas, in pixels
* @param bottom bottom position of the line relative to input canvas, in pixels
* @param text current text
* @param start start character index of the line
* @param end end character index of the line
* @param lineNumber line number in the current text layout
*/
void drawBackground(@NonNull Canvas canvas, @NonNull Paint paint,
@Px int left, @Px int right,
@Px int top, @Px int baseline, @Px int bottom,
@NonNull CharSequence text, int start, int end,
int lineNumber);
/**
* Default implementation of the {@link LineBackgroundSpan}, which changes the background
* color of the lines to which the span is attached.
* <p>
* For example, an <code>LineBackgroundSpan</code> can be used like this:
* <pre>
* String text = "This is a multiline text. LineBackgroundSpan is applied here. This is a multiline text.";
* SpannableString string = new SpannableString(text);
* string.setSpan(new LineBackgroundSpan.Standard(Color.YELLOW), 26, 61, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
* </pre>
* <img src="{@docRoot}reference/android/images/text/style/linebackgroundspan.png" />
* <figcaption>Text with <code>LineBackgroundSpan</code></figcaption>
*/
class Standard implements LineBackgroundSpan, ParcelableSpan {
private final int mColor;
/**
* Constructor taking a color integer.
*
* @param color Color integer that defines the background color.
*/
public Standard(@ColorInt int color) {
mColor = color;
}
/**
* Creates a {@link LineBackgroundSpan.Standard} from a parcel
*/
public Standard(@NonNull Parcel src) {
mColor = src.readInt();
}
@Override
public int getSpanTypeId() {
return getSpanTypeIdInternal();
}
/** @hide */
@Override
public int getSpanTypeIdInternal() {
return TextUtils.LINE_BACKGROUND_SPAN;
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(@NonNull Parcel dest, int flags) {
writeToParcelInternal(dest, flags);
}
/** @hide */
@Override
public void writeToParcelInternal(@NonNull Parcel dest, int flags) {
dest.writeInt(mColor);
}
/**
* @return the color of this span.
* @see Standard#Standard(int)
*/
@ColorInt
public final int getColor() {
return mColor;
}
@Override
public void drawBackground(@NonNull Canvas canvas, @NonNull Paint paint,
@Px int left, @Px int right,
@Px int top, @Px int baseline, @Px int bottom,
@NonNull CharSequence text, int start, int end,
int lineNumber) {
final int originColor = paint.getColor();
paint.setColor(mColor);
canvas.drawRect(left, top, right, bottom, paint);
paint.setColor(originColor);
}
}
}
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