MainActivity.kt
package com.cfsuman.kotlintutorials
import android.app.Activity
import android.content.Context
import android.graphics.*
import android.os.Bundle
import android.widget.*
import java.io.IOException
class MainActivity : Activity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// get the widgets reference from XML layout
val imageView = findViewById<ImageView>(R.id.imageView)
val imageView2 = findViewById<ImageView>(R.id.imageView2)
val textView = findViewById<TextView>(R.id.textView)
val seekBarRed = findViewById<SeekBar>(R.id.seekBarRed)
val seekBarGreen = findViewById<SeekBar>(R.id.seekBarGreen)
val seekBarBlue = findViewById<SeekBar>(R.id.seekBarBlue)
val tvIntensity = findViewById<TextView>(R.id.tvIntensity)
// get the bitmap from assets folder
val bitmap = assetsToBitmap("flower103.jpg")
bitmap?.apply {
// show original bitmap in first image view
imageView.setImageBitmap(this)
// show initial bitmap on second image view
imageView2.setImageBitmap(colorBalance())
// bitmap color balance on red seek bar change
seekBarRed.setOnSeekBarChangeListener(object:SeekBar
.OnSeekBarChangeListener{
override fun onProgressChanged(
seekBar: SeekBar?,
progress: Int,
fromUser: Boolean
) {
val intensityRed = progress - 100
val intensityGreen = seekBarGreen.progress - 100
val intensityBlue = seekBarBlue.progress - 100
// show color balanced bitmap on image view
imageView2.setImageBitmap(
colorBalance(
intensityRed, intensityGreen, intensityBlue
)
)
tvIntensity.text = "Intensity (Red $intensityRed :" +
" Green $intensityGreen : Blue $intensityBlue)"
}
override fun onStartTrackingTouch(seekBar: SeekBar?) {
}
override fun onStopTrackingTouch(seekBar: SeekBar?) {
}
})
// bitmap color balance on green seek bar change
seekBarGreen.setOnSeekBarChangeListener(object:SeekBar
.OnSeekBarChangeListener{
override fun onProgressChanged(
seekBar: SeekBar?,
progress: Int,
fromUser: Boolean
) {
val intensityRed = seekBarRed.progress - 100
val intensityGreen = progress - 100
val intensityBlue = seekBarBlue.progress - 100
// show color balanced bitmap on image view
imageView2.setImageBitmap(
colorBalance(
intensityRed, intensityGreen, intensityBlue
)
)
tvIntensity.text = "Intensity (Red $intensityRed :" +
" Green $intensityGreen : Blue $intensityBlue)"
}
override fun onStartTrackingTouch(seekBar: SeekBar?) {
}
override fun onStopTrackingTouch(seekBar: SeekBar?) {
}
})
// bitmap color balance on blue seek bar change
seekBarBlue.setOnSeekBarChangeListener(object:SeekBar
.OnSeekBarChangeListener{
override fun onProgressChanged(
seekBar: SeekBar?,
progress: Int,
fromUser: Boolean
) {
val intensityRed = seekBarRed.progress - 100
val intensityGreen = seekBarGreen.progress - 100
val intensityBlue = progress - 100
// show color balanced bitmap on image view
imageView2.setImageBitmap(
colorBalance(
intensityRed, intensityGreen, intensityBlue
)
)
tvIntensity.text = "Intensity (Red $intensityRed :" +
" Green $intensityGreen : Blue $intensityBlue)"
}
override fun onStartTrackingTouch(seekBar: SeekBar?) {
}
override fun onStopTrackingTouch(seekBar: SeekBar?) {
}
})
}
}
}
// extension function to get bitmap from assets
fun Context.assetsToBitmap(fileName:String):Bitmap?{
return try {
val stream = assets.open(fileName)
BitmapFactory.decodeStream(stream)
} catch (e: IOException) {
e.printStackTrace()
null
}
}
// extension function for bitmap color balance
fun Bitmap.colorBalance(
intensityRed:Int = 0,
intensityGreen:Int = 0,
intensityBlue:Int = 0
):Bitmap?{
val bitmap = copy(config,true)
var alpha:Int
var red:Int
var green:Int
var blue:Int
var pixel:Int
// scan through all pixels
for (x in 0 until width){
for (y in 0 until height){
pixel = getPixel(x,y)
alpha = Color.alpha(pixel)
red = Color.red(pixel)
green = Color.green(pixel)
blue = Color.blue(pixel)
red += intensityRed
if (red > 255) red = 255 else if (red < 0) red = 0
green += intensityGreen
if (green > 255) green = 255 else if (green < 0) green = 0
blue += intensityBlue
if (blue > 255) blue = 255 else if (blue < 0) blue = 0
val color = Color.argb(
alpha,
red,
green,
blue
)
bitmap.setPixel(x,y,color)
}
}
return bitmap
}
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:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/rootLayout"
android:background="#DCDCDC"
android:padding="24dp">
<ImageView
android:id="@+id/imageView"
android:layout_width="0dp"
android:layout_height="210dp"
android:layout_marginTop="8dp"
android:scaleType="centerCrop"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:text="Original Bitmap"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="@+id/imageView"
app:layout_constraintTop_toBottomOf="@+id/imageView" />
<ImageView
android:id="@+id/imageView2"
android:layout_width="0dp"
android:layout_height="210dp"
android:layout_marginTop="16dp"
android:scaleType="centerCrop"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView" />
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:padding="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@id/imageView2">
<TextView
android:id="@+id/tvIntensity"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:gravity="center_horizontal"
android:text="Channels Intensity"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<SeekBar
android:id="@+id/seekBarRed"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:max="200"
android:progress="100"
android:progressBackgroundTint="#ff0000"
android:progressTint="#ff0000"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/tvIntensity" />
<SeekBar
android:id="@+id/seekBarGreen"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:max="200"
android:progress="100"
android:progressBackgroundTint="#00ff00"
android:progressTint="#00ff00"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/seekBarRed" />
<SeekBar
android:id="@+id/seekBarBlue"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:max="200"
android:progress="100"
android:progressBackgroundTint="#0000ff"
android:progressTint="#0000ff"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/seekBarGreen" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
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