RenderNodeLayer.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.platform

import android.os.Build
import androidx.annotation.RequiresApi
import androidx.compose.ui.graphics.TransformOrigin
import androidx.compose.ui.geometry.Size
import androidx.compose.ui.graphics.Canvas
import androidx.compose.ui.graphics.CanvasHolder
import androidx.compose.ui.graphics.Matrix
import androidx.compose.ui.graphics.RectangleShape
import androidx.compose.ui.graphics.Shape
import androidx.compose.ui.graphics.nativeCanvas
import androidx.compose.ui.graphics.setFrom
import androidx.compose.ui.node.OwnedLayer
import androidx.compose.ui.unit.IntOffset
import androidx.compose.ui.unit.IntSize
import androidx.compose.ui.unit.LayoutDirection

/**
 * RenderNode implementation of OwnedLayer.
 */
@RequiresApi(Build.VERSION_CODES.M)
internal class RenderNodeLayer(
    val ownerView: AndroidComposeView,
    val drawBlock: (Canvas) -> Unit,
    val invalidateParentLayer: () -> Unit
) : OwnedLayer {
    /**
     * True when the RenderNodeLayer has been invalidated and not yet drawn.
     */
    private var isDirty = false
    private val outlineResolver = OutlineResolver(ownerView.density)
    private var isDestroyed = false
    private var androidMatrixCache: android.graphics.Matrix? = null
    private var drawnWithZ = false

    private val canvasHolder = CanvasHolder()

    /**
     * Local copy of the transform origin as GraphicsLayerModifier can be implemented
     * as a model object. Update this field within [updateLayerProperties] and use it
     * in [resize] or other methods
     */
    private var transformOrigin: TransformOrigin = TransformOrigin.Center

    private val renderNode = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
        RenderNodeApi29(ownerView)
    } else {
        RenderNodeApi23(ownerView)
    }.apply { setHasOverlappingRendering(true) }

    override val layerId: Long
        get() = renderNode.uniqueId

    override fun updateLayerProperties(
        scaleX: Float,
        scaleY: Float,
        alpha: Float,
        translationX: Float,
        translationY: Float,
        shadowElevation: Float,
        rotationX: Float,
        rotationY: Float,
        rotationZ: Float,
        cameraDistance: Float,
        transformOrigin: TransformOrigin,
        shape: Shape,
        clip: Boolean,
        layoutDirection: LayoutDirection
    ) {
        this.transformOrigin = transformOrigin
        val wasClippingManually = renderNode.clipToOutline && outlineResolver.clipPath != null
        renderNode.scaleX = scaleX
        renderNode.scaleY = scaleY
        renderNode.alpha = alpha
        renderNode.translationX = translationX
        renderNode.translationY = translationY
        renderNode.elevation = shadowElevation
        renderNode.rotationZ = rotationZ
        renderNode.rotationX = rotationX
        renderNode.rotationY = rotationY
        renderNode.cameraDistance = cameraDistance
        renderNode.pivotX = transformOrigin.pivotFractionX * renderNode.width
        renderNode.pivotY = transformOrigin.pivotFractionY * renderNode.height
        renderNode.clipToOutline = clip && shape !== RectangleShape
        renderNode.clipToBounds = clip && shape === RectangleShape
        val shapeChanged = outlineResolver.update(
            shape,
            renderNode.alpha,
            renderNode.clipToOutline,
            renderNode.elevation,
            layoutDirection
        )
        renderNode.setOutline(outlineResolver.outline)
        val isClippingManually = renderNode.clipToOutline && outlineResolver.clipPath != null
        if (wasClippingManually != isClippingManually || (isClippingManually && shapeChanged)) {
            invalidate()
        } else {
            triggerRepaint()
        }
        if (!drawnWithZ && renderNode.elevation > 0f) {
            invalidateParentLayer()
        }
    }

    override fun resize(size: IntSize) {
        val width = size.width
        val height = size.height
        renderNode.pivotX = transformOrigin.pivotFractionX * width
        renderNode.pivotY = transformOrigin.pivotFractionY * height
        if (renderNode.setPosition(
                renderNode.left,
                renderNode.top,
                renderNode.left + width,
                renderNode.top + height
            )
        ) {
            outlineResolver.update(Size(width.toFloat(), height.toFloat()))
            renderNode.setOutline(outlineResolver.outline)
            invalidate()
        }
    }

    override fun move(position: IntOffset) {
        val oldLeft = renderNode.left
        val oldTop = renderNode.top
        val newLeft = position.x
        val newTop = position.y
        if (oldLeft != newLeft || oldTop != newTop) {
            renderNode.offsetLeftAndRight(newLeft - oldLeft)
            renderNode.offsetTopAndBottom(newTop - oldTop)
            triggerRepaint()
        }
    }

    override fun invalidate() {
        if (!isDirty && !isDestroyed) {
            ownerView.invalidate()
            ownerView.dirtyLayers += this
            isDirty = true
        }
    }

    /**
     * This only triggers the system so that it knows that some kind of painting
     * must happen without actually causing the layer to be invalidated and have
     * to re-record its drawing.
     */
    private fun triggerRepaint() {
        // onDescendantInvalidated is only supported on O+
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            WrapperRenderNodeLayerHelperMethods.onDescendantInvalidated(ownerView)
        } else {
            ownerView.invalidate()
        }
    }

    override fun drawLayer(canvas: Canvas) {
        val androidCanvas = canvas.nativeCanvas
        if (androidCanvas.isHardwareAccelerated) {
            updateDisplayList()
            drawnWithZ = renderNode.elevation > 0f
            if (drawnWithZ) {
                canvas.enableZ()
            }
            renderNode.drawInto(androidCanvas)
            if (drawnWithZ) {
                canvas.disableZ()
            }
        } else {
            drawBlock(canvas)
        }
        isDirty = false
    }

    override fun updateDisplayList() {
        if (isDirty || !renderNode.hasDisplayList) {
            val clipPath = if (renderNode.clipToOutline) outlineResolver.clipPath else null

            renderNode.record(canvasHolder, clipPath, drawBlock)

            isDirty = false
        }
    }

    override fun destroy() {
        isDestroyed = true
        ownerView.dirtyLayers -= this
        ownerView.requestClearInvalidObservations()
    }

    override fun getMatrix(matrix: Matrix) {
        val androidMatrix = androidMatrixCache ?: android.graphics.Matrix().also {
            androidMatrixCache = it
        }
        renderNode.getMatrix(androidMatrix)
        matrix.setFrom(androidMatrix)
    }
}

/**
 * This class is here to ensure that the classes that use this API will get verified and can be
 * AOT compiled. It is expected that this class will soft-fail verification, but the classes
 * which use this method will pass.
 */
@RequiresApi(Build.VERSION_CODES.O)
internal object WrapperRenderNodeLayerHelperMethods {
    @androidx.annotation.DoNotInline
    fun onDescendantInvalidated(ownerView: AndroidComposeView) {
        ownerView.parent?.onDescendantInvalidated(ownerView, ownerView)
    }
}