| /* |
| * Copyright 2020 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.ui.desktop |
| |
| import androidx.compose.ui.graphics.Color |
| import androidx.compose.ui.graphics.toArgb |
| import androidx.compose.ui.text.AnnotatedString |
| import androidx.compose.ui.text.ParagraphIntrinsics |
| import androidx.compose.ui.text.Placeholder |
| import androidx.compose.ui.text.SpanStyle |
| import androidx.compose.ui.text.SpanStyleRange |
| import androidx.compose.ui.text.TextStyle |
| import androidx.compose.ui.text.font.Font |
| import androidx.compose.ui.unit.Density |
| import androidx.compose.ui.unit.TextUnit |
| import kotlin.math.ceil |
| import org.jetbrains.skija.paragraph.Paragraph |
| import org.jetbrains.skija.paragraph.ParagraphBuilder |
| import org.jetbrains.skija.paragraph.ParagraphStyle |
| import org.jetbrains.skija.paragraph.TextStyle as SkTextStyle |
| |
| internal class DesktopParagraphIntrinsics( |
| val text: String, |
| style: TextStyle, |
| spanStyles: List<SpanStyleRange>, |
| @Suppress("UNUSED_PARAMETER") placeholders: List<AnnotatedString.Range<Placeholder>>, |
| @Suppress("UNUSED_PARAMETER") density: Density, |
| resourceLoader: Font.ResourceLoader |
| ) : ParagraphIntrinsics { |
| |
| val fontLoader = resourceLoader as FontLoader |
| val para: Paragraph |
| init { |
| para = buildParagraph(text, style, spanStyles) |
| |
| para.layout(Float.POSITIVE_INFINITY) |
| } |
| |
| override val minIntrinsicWidth = ceil(para.getMinIntrinsicWidth()) |
| override val maxIntrinsicWidth = ceil(para.getMaxIntrinsicWidth()) |
| |
| /** |
| * SkParagraph styles model doesn't match Compose's one. |
| * SkParagraph has only a stack-based push/pop styles interface that works great with Span |
| * trees. |
| * But in Compose we have a list of SpanStyles attached to arbitrary ranges, possibly |
| * overlapped, where a position in the list denotes style's priority |
| * We map Compose styles to SkParagraph styles by projecting every range start/end to single |
| * positions line and maintaining a list of active styles while building a paragraph. This list |
| * of active styles is being compiled into single SkParagraph's style for every chunk of text |
| */ |
| private fun buildParagraph( |
| text: String, |
| textStyle: TextStyle, |
| spanStyles: List<SpanStyleRange> |
| ): Paragraph { |
| val cuts = spansToCuts(spanStyles) |
| |
| var pos = 0 |
| val ps = textStyleToParagraphStyle(textStyle) |
| val pb = ParagraphBuilder(ps, fontLoader.fonts) |
| // TODO: for some reasons paragraph style doesn't apply to text. maybe it's Skia bug, |
| // we need to investigate |
| val currentStyles = mutableListOf(Pair(0, textStyle.toSpanStyle())) |
| pb.pushStyle(textStylesToSkStyle(currentStyles)!!) |
| |
| for (cut in cuts) { |
| pb.addText(text.subSequence(pos, cut.position).toString()) |
| pb.popStyle() |
| |
| when (cut.instruction) { |
| StyleInstruction.ADD -> currentStyles.add(Pair(cut.priority, cut.style)) |
| StyleInstruction.REMOVE -> currentStyles.remove(Pair(cut.priority, cut.style)) |
| } |
| |
| textStylesToSkStyle(currentStyles)?.let { ts -> |
| pb.pushStyle(ts) |
| } |
| pos = cut.position |
| } |
| |
| pb.addText(text.subSequence(pos, text.length).toString()) |
| |
| return pb.build() |
| } |
| |
| private enum class StyleInstruction { |
| ADD, |
| REMOVE |
| } |
| |
| private data class Cut( |
| val position: Int, |
| val priority: Int, |
| val style: SpanStyle, |
| val instruction: StyleInstruction |
| ) |
| |
| private fun spansToCuts(spans: List<SpanStyleRange>): List<Cut> { |
| val positions = mutableMapOf<Int, Cut>() |
| for ((i, span) in spans.withIndex()) { |
| positions[span.start] = Cut(span.start, i, span.item, StyleInstruction.ADD) |
| positions[span.end] = Cut(span.end, i, span.item, StyleInstruction.REMOVE) |
| } |
| |
| val cuts = ArrayList<Cut>(positions.size) |
| |
| for (v in positions.toSortedMap().values) { |
| cuts.add(v) |
| } |
| return cuts |
| } |
| |
| private fun textStyleToParagraphStyle(style: TextStyle): ParagraphStyle { |
| val pStyle = ParagraphStyle() |
| val textStyle = SkTextStyle() |
| applyStyles(style.toSpanStyle(), textStyle) |
| pStyle.setTextStyle(textStyle) |
| return pStyle |
| } |
| |
| private fun applyStyles(from: SpanStyle, to: SkTextStyle) { |
| if (from.color != Color.Unset) { |
| to.setColor(from.color.toArgb()) |
| } |
| from.fontFamily?.let { |
| val fontFamilies = fontLoader.ensureRegistered(it) |
| to.setFontFamilies(fontFamilies.toTypedArray()) |
| } |
| // TODO: support [TextUnit.Em] |
| if (from.fontSize != TextUnit.Inherit) { |
| to.setFontSize(from.fontSize.value) |
| } |
| } |
| |
| private fun textStylesToSkStyle(styles: List<Pair<Int, SpanStyle>>): SkTextStyle? { |
| if (styles.isEmpty()) { |
| return null |
| } |
| val skStyle = SkTextStyle() |
| for (s in styles.sortedBy { (priority, _) -> priority }.map { (_, v) -> v }) { |
| applyStyles(s, skStyle) |
| } |
| return skStyle |
| } |
| } |