| /* |
| * Copyright 2019 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 androidx.compose.ui.text.android.style |
| |
| import android.graphics.Paint.FontMetricsInt |
| import androidx.compose.ui.text.android.InternalPlatformTextApi |
| |
| /** |
| * The span which modifies the height of the covered paragraphs. A paragraph is defined as a |
| * segment of string divided by '\n' character. To make sure the span work as expected, the |
| * boundary of this span should align with paragraph boundary. |
| * @constructor Create a LineHeightSpan which sets the line height to `height` physical pixels. |
| * @param lineHeight The specified line height in pixel unit, which is the space between the |
| * baseline of adjacent lines. |
| * |
| * @suppress |
| */ |
| @InternalPlatformTextApi |
| class LineHeightSpan(val lineHeight: Int) : android.text.style.LineHeightSpan { |
| override fun chooseHeight( |
| text: CharSequence, |
| start: Int, |
| end: Int, |
| spanstartVertical: Int, |
| lineHeight: Int, |
| fontMetricsInt: FontMetricsInt |
| ) { // In StaticLayout, line height is computed with descent - ascent |
| val currentHeight = fontMetricsInt.descent - fontMetricsInt.ascent |
| // If current height is not positive, do nothing. |
| if (currentHeight <= 0) { |
| return |
| } |
| val ratio = this.lineHeight * 1.0f / currentHeight |
| fontMetricsInt.descent = |
| Math.ceil(fontMetricsInt.descent * ratio.toDouble()).toInt() |
| fontMetricsInt.ascent = fontMetricsInt.descent - this.lineHeight |
| } |
| } |