packages/SystemUI/src/com/android/systemui/mediaprojection/appselector/view/MediaProjectionTaskView.kt

/*
 * Copyright (C) 2022 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 com.android.systemui.mediaprojection.appselector.view

import android.content.Context
import android.graphics.BitmapShader
import android.graphics.Canvas
import android.graphics.Color
import android.graphics.Paint
import android.graphics.Rect
import android.graphics.Shader
import android.util.AttributeSet
import android.view.View
import android.view.WindowManager
import androidx.core.content.getSystemService
import androidx.core.content.res.use
import com.android.internal.R as AndroidR
import com.android.systemui.R
import com.android.systemui.mediaprojection.appselector.data.RecentTask
import com.android.systemui.shared.recents.model.ThumbnailData
import com.android.systemui.shared.recents.utilities.PreviewPositionHelper
import com.android.systemui.shared.recents.utilities.Utilities.isLargeScreen

/**
 * Custom view that shows a thumbnail preview of one recent task based on [ThumbnailData].
 * It handles proper cropping and positioning of the thumbnail using [PreviewPositionHelper].
 */
class MediaProjectionTaskView
@JvmOverloads
constructor(context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0) :
    View(context, attrs, defStyleAttr) {

    private val defaultBackgroundColor: Int

    init {
        val backgroundColorAttribute = intArrayOf(android.R.attr.colorBackgroundFloating)
        defaultBackgroundColor =
            context.obtainStyledAttributes(backgroundColorAttribute).use {
                it.getColor(/* index= */ 0, /* defValue= */ Color.BLACK)
            }
    }

    private val windowManager: WindowManager = context.getSystemService()!!
    private val paint = Paint(Paint.ANTI_ALIAS_FLAG)
    private val backgroundPaint =
        Paint(Paint.ANTI_ALIAS_FLAG).apply { color = defaultBackgroundColor }
    private val cornerRadius =
        context.resources.getDimensionPixelSize(
            R.dimen.media_projection_app_selector_task_rounded_corners
        )
    private val previewPositionHelper = PreviewPositionHelper()
    private val previewRect = Rect()

    private var task: RecentTask? = null
    private var thumbnailData: ThumbnailData? = null

    private var bitmapShader: BitmapShader? = null

    fun bindTask(task: RecentTask?, thumbnailData: ThumbnailData?) {
        this.task = task
        this.thumbnailData = thumbnailData

        // Strip alpha channel to make sure that the color is not semi-transparent
        val color = (task?.colorBackground ?: Color.BLACK) or 0xFF000000.toInt()

        paint.color = color
        backgroundPaint.color = color

        refresh()
    }

    override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
        updateThumbnailMatrix()
        invalidate()
    }

    override fun onDraw(canvas: Canvas) {
        // Always draw the background since the snapshots might be translucent or partially empty
        // (For example, tasks been reparented out of dismissing split root when drag-to-dismiss
        // split screen).
        canvas.drawRoundRect(
            0f,
            1f,
            width.toFloat(),
            (height - 1).toFloat(),
            cornerRadius.toFloat(),
            cornerRadius.toFloat(),
            backgroundPaint
        )

        val drawBackgroundOnly = task == null || bitmapShader == null || thumbnailData == null
        if (drawBackgroundOnly) {
            return
        }

        // Draw the task thumbnail using bitmap shader in the paint
        canvas.drawRoundRect(
            0f,
            0f,
            width.toFloat(),
            height.toFloat(),
            cornerRadius.toFloat(),
            cornerRadius.toFloat(),
            paint
        )
    }

    private fun refresh() {
        val thumbnailBitmap = thumbnailData?.thumbnail

        if (thumbnailBitmap != null) {
            thumbnailBitmap.prepareToDraw()
            bitmapShader =
                BitmapShader(thumbnailBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP)
            paint.shader = bitmapShader
            updateThumbnailMatrix()
        } else {
            bitmapShader = null
            paint.shader = null
        }

        invalidate()
    }

    private fun updateThumbnailMatrix() {
        previewPositionHelper.isOrientationChanged = false

        val bitmapShader = bitmapShader ?: return
        val thumbnailData = thumbnailData ?: return
        val display = context.display ?: return
        val windowMetrics = windowManager.maximumWindowMetrics

        previewRect.set(0, 0, thumbnailData.thumbnail.width, thumbnailData.thumbnail.height)

        val currentRotation: Int = display.rotation
        val displayWidthPx = windowMetrics.bounds.width()
        val displayHeightPx = windowMetrics.bounds.height()
        val isRtl = layoutDirection == LAYOUT_DIRECTION_RTL
        val isLargeScreen = isLargeScreen(context)
        val taskbarSize =
            if (isLargeScreen) {
                resources.getDimensionPixelSize(AndroidR.dimen.taskbar_frame_height)
            } else {
                0
            }

        previewPositionHelper.updateThumbnailMatrix(
            previewRect,
            thumbnailData,
            measuredWidth,
            measuredHeight,
            displayWidthPx,
            displayHeightPx,
            taskbarSize,
            isLargeScreen,
            currentRotation,
            isRtl
        )

        bitmapShader.setLocalMatrix(previewPositionHelper.matrix)
        paint.shader = bitmapShader
    }
}