在画布中调整位图

Question

我正在为画布创建背景，但无法让图像适合屏幕，它只显示图像的中心部分。我尝试过createScaledBitmap调用显示指标但没有成功，还在drawBitmap中调用了Rect和ReEctF，我不知道我做错了什么。

class DrawStars(context: Context): View(context) {

    private var posX = 500f
    private var posY = 800f
    private var drawcolor: Int = ResourcesCompat.getColor(resources, R.color.black, null)

    private val paint =  Paint().apply{
        color = drawcolor
        style = Paint.Style.STROKE
        isAntiAlias = true
    }

    val dm = resources.displayMetrics
    val fwidth = dm.density * dm.widthPixels
    val fheight = dm.density * dm.heightPixels
    private var background = BitmapFactory.decodeResource(resources, R.drawable.fondo_sector2)
    //var resized: Bitmap = Bitmap.createScaledBitmap(background, fwidth.toInt(), fheight.toInt(), true)
    private var bitmap1 = BitmapFactory.decodeResource(resources, R.drawable.star1)


    override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)
        canvas.drawBitmap(background, 0f, 0f, paint)
        //canvas.drawBitmap(resized, 0f, 0f, paint)
        canvas.drawBitmap(bitmap1, posX, posY, paint)
    }

}`

Answer 1

技巧是使用createScaledBitmap，我不确定这是否是正确的解决方案，但至少它有效。

private val bar = getActionBarHeight()
private val dm: DisplayMetrics = resources.displayMetrics
private var bitmap = BitmapFactory.decodeResource(resources, R.drawable.fondo_sector)
private val background = Bitmap.createScaledBitmap(
    bitmap, dm.widthPixels, dm.heightPixels + bar, true)

override fun onDraw(canvas: Canvas) {
    super.onDraw(canvas)
    canvas.drawBitmap(background, 0f, 0f, p)

}

最后，隐藏操作栏

private fun getActionBarHeight(): Int {
    // Height of action bar
    val ta = context.theme.obtainStyledAttributes(
        intArrayOf(android.R.attr.actionBarSize)
    )
    val actionBarHeight = ta.getDimension(0, 0f).toInt()
    return actionBarHeight
}