MainActivity.kt
package com.example.jetpack
import android.content.Context
import android.graphics.*
import android.os.Bundle
import android.util.TypedValue
import androidx.appcompat.app.AppCompatActivity
import androidx.core.graphics.drawable.RoundedBitmapDrawable
import androidx.core.graphics.drawable.RoundedBitmapDrawableFactory
import kotlinx.android.synthetic.main.activity_main.*
import java.io.IOException
import kotlin.math.min
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// get bitmap from assets folder
val bitmap: Bitmap? = assetsToBitmap("flower10.jpg")
// show the bitmap on first image view
bitmap?.apply { imageView.setImageBitmap(this) }
// make the bitmap circular with specified border
bitmap?.circularWithBorder(
context = applicationContext,
borderWidth = 7.dpToPixels(applicationContext),
borderColor = Color.parseColor("#004225")
)?.apply {
imageView2.setImageDrawable(this)
}
}
}
// extension function to make a bitmap circular with border
fun Bitmap.circularWithBorder(
context: Context,
borderWidth: Float = 25F,
borderColor: Int = Color.BLACK
): RoundedBitmapDrawable? {
// calculate the bitmap diameter and radius
val diameter = (min(width, height) + borderWidth * 2).toInt()
val radius = diameter / 2F
val bitmap = Bitmap.createBitmap(diameter, diameter, Bitmap.Config.ARGB_8888)
val canvas = Canvas(bitmap)
canvas.drawColor(Color.WHITE)
// draw bitmap at canvas center
canvas.drawBitmap(
this, // bitmap
(diameter - this.width)/2F, // left
(diameter - this.height)/2F, // top
null // paint
)
// pa to draw circular border
Paint().apply {
style = Paint.Style.STROKE
// stroke is always centered so double it
strokeWidth = borderWidth * 2F
color = borderColor
isAntiAlias = true
// draw circular border on canvas
canvas.drawCircle(canvas.width / 2F,canvas.width / 2F,radius,this)
}
// return circular bitmap drawable with border
return RoundedBitmapDrawableFactory.create(context.resources, bitmap).apply {
isCircular = true
setAntiAlias(true)
}
}
// extension function to convert dp to equivalent pixels
fun Int.dpToPixels(context: Context):Float = TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, this.toFloat(), context.resources.displayMetrics
)
// extension function to get bitmap from assets
fun Context.assetsToBitmap(fileName: String): Bitmap?{
return try {
with(assets.open(fileName)){
BitmapFactory.decodeStream(this)
}
} catch (e: IOException) { null }
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/constraintLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#EDEAE0"
tools:context=".MainActivity">
<ImageView
android:id="@+id/imageView"
android:layout_width="0dp"
android:layout_height="280dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:srcCompat="@tools:sample/avatars" />
<ImageView
android:id="@+id/imageView2"
android:layout_width="0dp"
android:layout_height="280dp"
android:layout_marginStart="8dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/imageView"
tools:srcCompat="@tools:sample/avatars" />
</androidx.constraintlayout.widget.ConstraintLayout>

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