Android - in Android Pie (API 28) RadialGradient draws a rectangle instead of a circle

Question

I'm trying to simulate a TorchView with a background image and a foreground image. It works well on API 27 and below, but draw a rectangle on API 28.

Any idea why it doesn't work on Android Pie?

On API 27 and below	API 28

Torch View class:

class TorchView : View, OnTouchListener {

    var mBitmapBackground: Bitmap? = null
    var mBitmapForeground: Bitmap? = null
    var mMask: Bitmap? = null
    private var mPosX = 0f
    private var mPosY = 0f

    private lateinit var paintMask: Paint
    private lateinit var paintBackground: Paint
    private lateinit var paintForeground: Paint

    private var radius = 150

    constructor(context: Context) : super(context) {
        init()
    }

    constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
        init()
    }

    fun initBitmaps(bitmapBackground: Bitmap, bitmapForeground: Bitmap, radius: Int){
        this.radius = radius
        mBitmapBackground = bitmapBackground
        mBitmapForeground = bitmapForeground
        mMask = makeRadGrad()
        mPosX = (bitmapBackground.width/2 - radius).toFloat()
        mPosY = (bitmapBackground.height/2 - radius).toFloat()
        invalidate()
    }

    fun init() {
        paintBackground = Paint()

        paintMask = Paint()
        paintMask.xfermode = PorterDuffXfermode(PorterDuff.Mode.CLEAR)

        paintForeground = Paint()
        paintForeground.xfermode = PorterDuffXfermode(PorterDuff.Mode.DST_OVER)

        isFocusable = true
        isFocusableInTouchMode = true
        this.setOnTouchListener(this)
    }

    public override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)

        val mask = mMask
        val bitmapForeground = mBitmapBackground
        val bitmapBackground = mBitmapForeground
        if(mask != null && bitmapForeground != null && bitmapBackground != null){
            canvas.save()
            canvas.drawBitmap(bitmapBackground, 0f, 0f, paintBackground)
            canvas.drawBitmap(mask, mPosX, mPosY, paintMask)
            canvas.drawBitmap(bitmapForeground, 0f, 0f, paintForeground)
            canvas.restore()
        }
    }

    private fun makeRadGrad(): Bitmap {
        val gradient = RadialGradient(
            radius.toFloat(), radius.toFloat(), radius.toFloat(), -0xff0100,
            0x00000000, android.graphics.Shader.TileMode.CLAMP
        )
        val p = Paint()
        p.isDither = true
        p.shader = gradient

        val bitmap = Bitmap.createBitmap(radius*2, radius*2, Config.ARGB_8888)
        val c = Canvas(bitmap)
        c.drawCircle(radius.toFloat(), radius.toFloat(), radius.toFloat(), p)

        return bitmap
    }

    override fun onTouch(v: View?, event: MotionEvent): Boolean {
        mPosX = event.x - radius
        mPosY = event.y - radius
        invalidate()
        return true
    }
}

fancyyou · Accepted Answer · 2019-05-30 08:57:15Z

1

check this https://issuetracker.google.com/issues/111819103

try this

 public override fun onDraw(canvas: Canvas) {
    super.onDraw(canvas)
    val mask = mMask
    val bitmapForeground = mBitmapBackground
    val bitmapBackground = mBitmapForeground
    if(mask != null && bitmapForeground != null && bitmapBackground != null){
        canvas.save()
        canvas.drawBitmap(bitmapBackground, 0f, 0f, paintBackground)
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
            makeRadGradP(canvas, bitmapForeground)
        } else {
            canvas.drawBitmap(mask, mPosX, mPosY, paintMask)
            canvas.drawBitmap(bitmapForeground, 0f, 0f, paintForeground)
         }
        canvas.restore()
    }
}

private fun makeRadGradP(canvas: Canvas, bm: Bitmap) {
        val paint = Paint()
        paint.style = Paint.Style.FILL
        val shader = BitmapShader(bm, TileMode.CLAMP, TileMode.CLAMP)
        paint.shader = shader
        val corners = Path()
        corners.addCircle(mPosX + radius, mPosY + radius, radius.toFloat(), Path.Direction.CW)
        canvas.drawPath(corners, paint)

        val gradient = RadialGradient(
                mPosX + radius, mPosY + radius, radius.toFloat(), 0x00000000,
                Color.parseColor("#df000000"), TileMode.CLAMP
        )
        val p = Paint()
        p.isDither = true
        p.shader = gradient
        canvas.drawCircle(mPosX + radius, mPosY + radius, radius.toFloat(), p)
 }

answered May 30, 2019 at 8:57

fancyyou

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1 Comment

sokarcreative Over a year ago

Thanks a lot, this is exactly what I needed. Thanks for linking the issue tracker.

Jeffery Ma · Accepted Answer · 2019-05-29 07:06:16Z

1

According to the Official Document

PorterDuff was deprecated in Android API 28

You should replace PorterDuff with BlendMode

Maybe you should do some compatible work on Android API 28

edited May 29, 2019 at 7:06

answered May 29, 2019 at 3:47

Jeffery Ma

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2 Comments

sokarcreative Over a year ago

Android API 28 is Pie not Q, Q is still in preview :/

Jeffery Ma Over a year ago

Oh, it seems i made a mistake.

Fedor · Accepted Answer · 2024-10-30 11:07:35Z

class:

class TorchView : View, OnTouchListener {

    var mBitmapBackground: Bitmap? = null
    var mBitmapForeground: Bitmap? = null
    var mMask: Bitmap? = null
    private var mPosX = 0f
    private var mPosY = 0f

    private lateinit var paintMask: Paint
    private lateinit var paintBackground: Paint
    private lateinit var paintForeground: Paint

    private var radius = 150

    constructor(context: Context) : super(context) {
        init()
    }

    constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
        init()
    }

    fun initBitmaps(bitmapBackground: Bitmap, bitmapForeground: Bitmap, radius: Int){
        this.radius = radius
        mBitmapBackground = bitmapBackground
        mBitmapForeground = bitmapForeground
        mMask = makeRadGrad()
        mPosX = (bitmapBackground.width/2 - radius).toFloat()
        mPosY = (bitmapBackground.height/2 - radius).toFloat()
        invalidate()
    }

    fun init() {
        paintBackground = Paint()

        paintMask = Paint()
        paintMask.xfermode = PorterDuffXfermode(PorterDuff.Mode.CLEAR)

        paintForeground = Paint()
        paintForeground.xfermode = PorterDuffXfermode(PorterDuff.Mode.DST_OVER)

        isFocusable = true
        isFocusableInTouchMode = true
        this.setOnTouchListener(this)
    }

    public override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)

        val mask = mMask
        val bitmapForeground = mBitmapBackground
        val bitmapBackground = mBitmapForeground
        if(mask != null && bitmapForeground != null && bitmapBackground != null){
            canvas.save()
            canvas.drawBitmap(bitmapBackground, 0f, 0f, paintBackground)
            canvas.drawBitmap(mask, mPosX, mPosY, paintMask)
            canvas.drawBitmap(bitmapForeground, 0f, 0f, paintForeground)
            canvas.restore()
        }
    }

    private fun makeRadGrad(): Bitmap {
        val gradient = RadialGradient(
            radius.toFloat(), radius.toFloat(), radius.toFloat(), -0xff0100,
            0x00000000, android.graphics.Shader.TileMode.CLAMP
        )
        val p = Paint()
        p.isDither = true
        p.shader = gradient

        val bitmap = Bitmap.createBitmap(radius*2, radius*2, Config.ARGB_8888)
        val c = Canvas(bitmap)
        c.drawCircle(radius.toFloat(), radius.toFloat(), radius.toFloat(), p)

        return bitmap
    }

    override fun onTouch(v: View?, event: MotionEvent): Boolean {
        mPosX = event.x - radius
        mPosY = event.y - radius
        invalidate()
        return true
    }
}

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