| /* |
| * 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.IntRange; |
| import android.annotation.NonNull; |
| import android.annotation.Px; |
| import android.graphics.Paint; |
| import android.os.Parcel; |
| import android.text.ParcelableSpan; |
| import android.text.TextPaint; |
| import android.text.TextUtils; |
| |
| import com.android.internal.util.Preconditions; |
| |
| /** |
| * The classes that affect the line height of paragraph should implement this interface. |
| */ |
| public interface LineHeightSpan extends ParagraphStyle, WrapTogetherSpan { |
| /** |
| * Classes that implement this should define how the height is being calculated. |
| * |
| * @param text the text |
| * @param start the start of the line |
| * @param end the end of the line |
| * @param spanstartv the start of the span |
| * @param lineHeight the line height |
| * @param fm font metrics of the paint, in integers |
| */ |
| public void chooseHeight(CharSequence text, int start, int end, |
| int spanstartv, int lineHeight, |
| Paint.FontMetricsInt fm); |
| |
| /** |
| * The classes that affect the line height of paragraph with respect to density, |
| * should implement this interface. |
| */ |
| public interface WithDensity extends LineHeightSpan { |
| |
| /** |
| * Classes that implement this should define how the height is being calculated. |
| * |
| * @param text the text |
| * @param start the start of the line |
| * @param end the end of the line |
| * @param spanstartv the start of the span |
| * @param lineHeight the line height |
| * @param paint the paint |
| */ |
| public void chooseHeight(CharSequence text, int start, int end, |
| int spanstartv, int lineHeight, |
| Paint.FontMetricsInt fm, TextPaint paint); |
| } |
| |
| /** |
| * Default implementation of the {@link LineHeightSpan}, which changes the line height of the |
| * attached paragraph. |
| * <p> |
| * For example, a paragraph with its line height equal to 100px can be set like this: |
| * <pre> |
| * SpannableString string = new SpannableString("This is a multiline paragraph. This is a multiline paragraph."); |
| * string.setSpan(new LineHeightSpan.Standard(100), 0, string.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); |
| * </pre> |
| * <img src="{@docRoot}reference/android/images/text/style/lineheightspan.png" /> |
| * <figcaption>Text with line height set to 100 pixels.</figcaption> |
| * <p> |
| * Notice that LineHeightSpan will change the line height of the entire paragraph, even though it |
| * covers only part of the paragraph. |
| * </p> |
| */ |
| class Standard implements LineHeightSpan, ParcelableSpan { |
| |
| private final @Px int mHeight; |
| /** |
| * Set the line height of the paragraph to <code>height</code> physical pixels. |
| */ |
| public Standard(@Px @IntRange(from = 1) int height) { |
| Preconditions.checkArgument(height > 0, "Height:" + height + "must be positive"); |
| mHeight = height; |
| } |
| |
| /** |
| * Constructor called from {@link TextUtils} to restore the span from a parcel |
| */ |
| public Standard(@NonNull Parcel src) { |
| mHeight = src.readInt(); |
| } |
| |
| /** |
| * Returns the line height specified by this span. |
| */ |
| @Px |
| public int getHeight() { |
| return mHeight; |
| } |
| |
| @Override |
| public int getSpanTypeId() { |
| return getSpanTypeIdInternal(); |
| } |
| |
| /** @hide */ |
| @Override |
| public int getSpanTypeIdInternal() { |
| return TextUtils.LINE_HEIGHT_SPAN; |
| } |
| |
| @Override |
| public int describeContents() { |
| return 0; |
| } |
| |
| @Override |
| public void writeToParcel(Parcel dest, int flags) { |
| writeToParcelInternal(dest, flags); |
| } |
| |
| /** @hide */ |
| @Override |
| public void writeToParcelInternal(@NonNull Parcel dest, int flags) { |
| dest.writeInt(mHeight); |
| } |
| |
| @Override |
| public void chooseHeight(@NonNull CharSequence text, int start, int end, |
| int spanstartv, int lineHeight, |
| @NonNull Paint.FontMetricsInt fm) { |
| final int originHeight = fm.descent - fm.ascent; |
| // If original height is not positive, do nothing. |
| if (originHeight <= 0) { |
| return; |
| } |
| final float ratio = mHeight * 1.0f / originHeight; |
| fm.descent = Math.round(fm.descent * ratio); |
| fm.ascent = fm.descent - mHeight; |
| } |
| } |
| } |