MainActivity.kt
package com.cfsuman.kotlintutorials
import android.app.Activity
import android.graphics.*
import android.os.Bundle
import android.widget.ImageView
import android.widget.TextView
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 textView = findViewById<TextView>(R.id.textView)
// draw text on canvas and get bitmap
val bitmap = drawText(
text = "Android",
textSize = 250F,
textColor = Color.parseColor("#333399"),
canvasColor = Color.parseColor("#A2A2D0"),
typeface = Typeface.SANS_SERIF,
style = Typeface.BOLD_ITALIC,
isUnderline = true
)
// show drawing on image view
imageView.setImageBitmap(bitmap)
// about canvas drawing
textView.text = "typeface : SANS_SERIF"
textView.append("\nstyle : BOLD_ITALIC")
textView.append("\ntext color #333399")
textView.append("\ncanvas color #A2A2D0")
textView.append("\ntext size : 250px")
textView.append("\nisUnderline : true")
}
}
// function to draw text on canvas
fun drawText(
text:String = "Text To Draw",
textColor:Int = Color.BLACK,
textSize:Float = 200F,
typeface: Typeface = Typeface.SERIF,
style:Int = Typeface.NORMAL,
isUnderline:Boolean = false,
canvasColor:Int = Color.WHITE
):Bitmap{
val bitmap = Bitmap.createBitmap(
1500,
750,
Bitmap.Config.ARGB_8888
)
// canvas to draw the text
val canvas = Canvas(bitmap).apply {
drawColor(canvasColor)
}
// paint to draw the text
val paint = Paint().apply {
isAntiAlias = true
color = textColor
// paint's text size in pixel units
this.textSize = textSize
this.typeface = typeface
// set typeface with style
setTypeface(Typeface.create(typeface,style))
// to underline text
if (isUnderline){flags = Paint.UNDERLINE_TEXT_FLAG}
}
// finally, draw the text on canvas
canvas.drawText(
text, // text to draw
// x-coordinate of the origin of the text being drawn
100F,
// y-coordinate of the baseline of the text being drawn
canvas.height/2F,
paint // paint used for the text e.g. color, size, style
)
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"
android:id="@+id/rootLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#DCDCDC"
android:padding="24dp">
<ImageView
android:id="@+id/imageView"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/textView"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:fontFamily="sans-serif"
android:text="Canvas"
android:textAlignment="center"
android:textSize="22sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/imageView" />
</androidx.constraintlayout.widget.ConstraintLayout>
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