TextPaintExtensions.kt
/*
* 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.compose.ui.text.platform.extensions
import android.graphics.Typeface
import android.os.Build
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.text.SpanStyle
import androidx.compose.ui.text.font.FontListFontFamily
import androidx.compose.ui.text.font.FontStyle
import androidx.compose.ui.text.font.FontSynthesis
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.intl.Locale
import androidx.compose.ui.text.intl.LocaleList
import androidx.compose.ui.text.platform.AndroidTextPaint
import androidx.compose.ui.text.platform.TypefaceAdapter
import androidx.compose.ui.text.style.BaselineShift
import androidx.compose.ui.text.style.TextGeometricTransform
import androidx.compose.ui.unit.Density
import androidx.compose.ui.unit.TextUnit
import androidx.compose.ui.unit.TextUnitType
@Suppress("DEPRECATION")
internal fun AndroidTextPaint.applySpanStyle(
style: SpanStyle,
typefaceAdapter: TypefaceAdapter,
density: Density
): SpanStyle {
when (style.fontSize.type) {
TextUnitType.Sp -> with(density) {
textSize = style.fontSize.toPx()
}
TextUnitType.Em -> {
textSize *= style.fontSize.value
}
TextUnitType.Unspecified -> {} // Do nothing
}
if (style.hasFontAttributes()) {
typeface = createTypeface(style, typefaceAdapter)
}
if (style.localeList != null && style.localeList != LocaleList.current) {
if (Build.VERSION.SDK_INT >= 24) {
textLocales = style.localeList.toAndroidLocaleList()
} else {
val locale = if (style.localeList.isEmpty()) {
Locale.current
} else {
style.localeList[0]
}
textLocale = locale.toJavaLocale()
}
}
when (style.letterSpacing.type) {
TextUnitType.Em -> { letterSpacing = style.letterSpacing.value }
TextUnitType.Sp -> {} // Sp will be handled by applying a span
TextUnitType.Unspecified -> {} // Do nothing
}
if (style.fontFeatureSettings != null && style.fontFeatureSettings != "") {
fontFeatureSettings = style.fontFeatureSettings
}
if (style.textGeometricTransform != null &&
style.textGeometricTransform != TextGeometricTransform.None
) {
textScaleX *= style.textGeometricTransform.scaleX
textSkewX += style.textGeometricTransform.skewX
}
// these parameters are also updated by the Paragraph.draw
setColor(style.color)
setShadow(style.shadow)
setTextDecoration(style.textDecoration)
// When FontFamily is a custom font(FontListFontFamily), it needs to be applied on Paint to
// compute empty paragraph height. Meanwhile, we also need a FontSpan for
// FontStyle/FontWeight span to work correctly.
// letterSpacing with unit Sp needs to be handled by span.
// baselineShift and bgColor is reset in the Android Layout constructor,
// therefore we cannot apply them on paint, have to use spans.
return SpanStyle(
fontFamily = if (style.fontFamily != null && style.fontFamily is FontListFontFamily) {
style.fontFamily
} else {
null
},
letterSpacing = if (style.letterSpacing.type == TextUnitType.Sp &&
style.letterSpacing.value != 0f
) {
style.letterSpacing
} else {
TextUnit.Unspecified
},
background = if (style.background == Color.Transparent) {
Color.Unspecified // No need to add transparent background for default text style.
} else {
style.background
},
baselineShift = if (style.baselineShift == BaselineShift.None) {
null
} else {
style.baselineShift
}
)
}
/**
* Returns true if this [SpanStyle] contains any font style attributes set.
*/
private fun SpanStyle.hasFontAttributes(): Boolean {
return fontFamily != null || fontStyle != null || fontWeight != null
}
private fun createTypeface(style: SpanStyle, typefaceAdapter: TypefaceAdapter): Typeface {
return typefaceAdapter.create(
fontFamily = style.fontFamily,
fontWeight = style.fontWeight ?: FontWeight.Normal,
fontStyle = style.fontStyle ?: FontStyle.Normal,
fontSynthesis = style.fontSynthesis ?: FontSynthesis.All
)
}