SurfaceGlow.kt
/*
* Copyright 2023 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.tv.material3
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.NativePaint
import androidx.compose.ui.graphics.Outline
import androidx.compose.ui.graphics.Paint
import androidx.compose.ui.graphics.Shape
import androidx.compose.ui.graphics.drawscope.ContentDrawScope
import androidx.compose.ui.graphics.drawscope.drawIntoCanvas
import androidx.compose.ui.graphics.toArgb
import androidx.compose.ui.node.DrawModifierNode
import androidx.compose.ui.node.ModifierNodeElement
import androidx.compose.ui.platform.InspectorInfo
import androidx.compose.ui.platform.LocalDensity
import androidx.compose.ui.platform.debugInspectorInfo
@Composable
internal fun Modifier.tvSurfaceGlow(
shape: Shape,
glow: Glow,
): Modifier {
val color = surfaceColorAtElevation(
color = glow.elevationColor,
elevation = glow.elevation
)
val glowBlurRadiusPx = with(LocalDensity.current) { glow.elevation.toPx() }
return then(
SurfaceGlowElement(
shape = shape,
glowBlurRadiusPx = glowBlurRadiusPx,
color = color,
inspectorInfo = debugInspectorInfo {
name = "tvSurfaceGlow"
properties["shape"] = shape
properties["glow"] = glow
}
)
)
}
private class SurfaceGlowElement(
private val shape: Shape,
private val glowBlurRadiusPx: Float,
private val color: Color,
private val inspectorInfo: InspectorInfo.() -> Unit
) : ModifierNodeElement<SurfaceGlowNode>() {
override fun create(): SurfaceGlowNode {
return SurfaceGlowNode(
shape = shape,
glowBlurRadiusPx = glowBlurRadiusPx,
color = color,
)
}
override fun update(node: SurfaceGlowNode) {
node.reactToUpdates(
newShape = shape,
newGlowBlurRadiusPx = glowBlurRadiusPx,
newColor = color
)
}
override fun InspectorInfo.inspectableProperties() {
inspectorInfo()
}
override fun hashCode(): Int {
var result = shape.hashCode()
result = 31 * result + glowBlurRadiusPx.hashCode()
result = 31 * result + color.hashCode()
return result
}
override fun equals(other: Any?): Boolean {
val otherTyped = other as? SurfaceGlowElement ?: return false
return shape == otherTyped.shape &&
glowBlurRadiusPx == otherTyped.glowBlurRadiusPx &&
color == otherTyped.color
}
}
private class SurfaceGlowNode(
private var shape: Shape,
private var glowBlurRadiusPx: Float,
private var color: Color,
) : DrawModifierNode, Modifier.Node() {
private var paint: Paint? = null
private var frameworkPaint: NativePaint? = null
// This value is lazily allocated
private var shapeOutlineCache: SurfaceShapeOutlineCache? = null
fun reactToUpdates(
newShape: Shape,
newGlowBlurRadiusPx: Float,
newColor: Color,
) {
shape = newShape
glowBlurRadiusPx = newGlowBlurRadiusPx
color = newColor
if (paint == null) {
initializePaint()
}
setShadowLayer()
}
override fun ContentDrawScope.draw() {
drawIntoCanvas { canvas ->
if (paint == null) {
initializePaint()
setShadowLayer()
}
if (shapeOutlineCache == null) {
shapeOutlineCache = SurfaceShapeOutlineCache(
shape = shape,
size = size,
layoutDirection = layoutDirection,
density = this
)
}
when (
val shapeOutline = shapeOutlineCache!!.updatedOutline(
shape = shape,
size = size,
layoutDirection = layoutDirection,
density = this
)
) {
is Outline.Rectangle -> canvas.drawRect(shapeOutline.rect, paint!!)
is Outline.Rounded -> {
val shapeCornerRadiusX = shapeOutline.roundRect.topLeftCornerRadius.x
val shapeCornerRadiusY = shapeOutline.roundRect.topLeftCornerRadius.y
canvas.drawRoundRect(
left = 0f,
top = 0f,
right = size.width,
bottom = size.height,
radiusX = shapeCornerRadiusX,
radiusY = shapeCornerRadiusY,
paint = paint!!
)
}
is Outline.Generic -> canvas.drawPath(shapeOutline.path, paint!!)
}
}
drawContent()
}
private fun initializePaint() {
paint = Paint()
frameworkPaint = paint!!.asFrameworkPaint()
}
private fun setShadowLayer() {
val transparentColor = color.copy(alpha = 0f).toArgb()
val shadowColor = color.toArgb()
frameworkPaint!!.color = transparentColor
frameworkPaint!!.setShadowLayer(
/* radius= */ glowBlurRadiusPx,
/* dx= */ 0f,
/* dy= */ 0f,
/* shadowColor= */ shadowColor
)
}
}