Android画布Canvas绘图scale，Kotlin-蒲公英云

Android画布Canvas绘图scale，Kotlin

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<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.LinearLayoutCompat xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/darker_gray"
    android:orientation="vertical"
    app:divider="@android:drawable/divider_horizontal_bright"
    app:dividerPadding="5dp"
    app:showDividers="beginning|middle|end">
    <ImageView
        android:id="@+id/iv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_margin="10dp"
        android:background="@drawable/ic_launcher_background"
        android:scaleType="fitCenter"
        android:src="@mipmap/pic" />
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <ImageView
            android:id="@+id/iv1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:background="@drawable/ic_launcher_background" />
        <ImageView
            android:id="@+id/iv2"
            android:layout_width="300px"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:background="@drawable/ic_launcher_background" />
        <ImageView
            android:id="@+id/iv3"
            android:layout_width="300px"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:background="@drawable/ic_launcher_background" />
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <ImageView
            android:id="@+id/iv4"
            android:layout_width="300px"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:background="@drawable/ic_launcher_background" />
        <ImageView
            android:id="@+id/iv5"
            android:layout_width="300px"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:background="@drawable/ic_launcher_background" />
        <ImageView
            android:id="@+id/iv6"
            android:layout_width="300px"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:background="@drawable/ic_launcher_background" />
    </LinearLayout>
</androidx.appcompat.widget.LinearLayoutCompat>
import android.graphics.Bitmap
import android.graphics.Canvas
import android.graphics.Color
import android.graphics.Paint
import android.graphics.RectF
import android.graphics.drawable.BitmapDrawable
import android.os.Bundle
import android.util.Log
import android.widget.ImageView
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.delay
import kotlinx.coroutines.launch
class MainActivity : AppCompatActivity() {
    private var iv: ImageView? = null
    private var iv1: ImageView? = null
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        iv = findViewById(R.id.iv)
        iv1 = findViewById(R.id.iv1)
        lifecycleScope.launch(Dispatchers.Main) {
            delay(500)
            f1()
        }
    }
    private fun f1() {
        val bitmap = ((iv?.drawable as BitmapDrawable).bitmap.copy(Bitmap.Config.ARGB_8888, true))
        //val bitmap = Bitmap.createBitmap(500, 500, Bitmap.Config.ARGB_8888)
        val canvas = Canvas(bitmap)
        //canvas.drawColor(Color.LTGRAY) //铺满
        val w = bitmap.width
        val h = bitmap.height
        Log.d("fly", "w=$w h=$h")
        val paint = Paint()
        paint.isAntiAlias = true
        paint.color = Color.RED
        paint.style = Paint.Style.FILL
        val left = 60f
        val top = 60f
        val rectF = RectF(left, top, left + w / 2, top + h / 2)
        canvas.drawRect(rectF, paint)
        canvas.scale(0.5f, 0.5f) //缩小。
        paint.color = Color.YELLOW
        canvas.drawRect(rectF, paint)
        canvas.scale(0.3f, 0.3f) //缩小。
        paint.color = Color.BLUE
        canvas.drawRect(rectF, paint)
        iv1?.setImageBitmap(bitmap)
    }
}

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