AndroidTextPaint.android.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
import android.text.TextPaint
import androidx.compose.ui.geometry.Size
import androidx.compose.ui.geometry.isSpecified
import androidx.compose.ui.graphics.Brush
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.ShaderBrush
import androidx.compose.ui.graphics.Shadow
import androidx.compose.ui.graphics.SolidColor
import androidx.compose.ui.graphics.isSpecified
import androidx.compose.ui.graphics.toArgb
import androidx.compose.ui.text.platform.extensions.correctBlurRadius
import androidx.compose.ui.text.style.TextDecoration
import androidx.compose.ui.text.style.modulate
import kotlin.math.roundToInt
internal class AndroidTextPaint(flags: Int, density: Float) : TextPaint(flags) {
init {
this.density = density
}
private var textDecoration: TextDecoration = TextDecoration.None
private var shadow: Shadow = Shadow.None
private var brush: Brush? = null
private var brushSize: Size? = null
fun setTextDecoration(textDecoration: TextDecoration?) {
val tmpTextDecoration = textDecoration ?: TextDecoration.None
if (this.textDecoration != tmpTextDecoration) {
this.textDecoration = tmpTextDecoration
isUnderlineText = TextDecoration.Underline in this.textDecoration
isStrikeThruText = TextDecoration.LineThrough in this.textDecoration
}
}
fun setShadow(shadow: Shadow?) {
val tmpShadow = shadow ?: Shadow.None
if (this.shadow != tmpShadow) {
this.shadow = tmpShadow
if (this.shadow == Shadow.None) {
clearShadowLayer()
} else {
setShadowLayer(
correctBlurRadius(this.shadow.blurRadius),
this.shadow.offset.x,
this.shadow.offset.y,
this.shadow.color.toArgb()
)
}
}
}
fun setColor(color: Color) {
if (color.isSpecified) {
val argbColor = color.toArgb()
if (this.color != argbColor) {
this.color = argbColor
}
this.shader = null
}
}
fun setBrush(brush: Brush?, size: Size, alpha: Float = Float.NaN) {
when (brush) {
null -> {
this.shader = null
this.brush = null
this.brushSize = null
}
is SolidColor -> {
this.shader = null
this.brush = null
this.brushSize = null
setColor(brush.value.modulate(alpha))
}
is ShaderBrush -> {
if (this.shader == null || this.brush != brush || this.brushSize != size) {
if (size.isSpecified) {
this.brush = brush
this.brushSize = size
this.shader = brush.createShader(size)
}
}
setAlpha(alpha)
}
}
}
}
/**
* Accepts an alpha value in the range [0f, 1f] then maps to an integer value
* in [0, 255] range.
*/
internal fun TextPaint.setAlpha(alpha: Float) {
if (!alpha.isNaN()) {
val alphaInt = alpha.coerceIn(0f, 1f).times(255).roundToInt()
setAlpha(alphaInt)
}
}