Android画布Canvas绘图scale，Kotlin
XML
<?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>
Kotlin
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)
}
}