MainActivity.kt
package com.cfsuman.kotlintutorials
import android.app.Activity
import android.graphics.*
import android.os.Bundle
import android.widget.ImageView
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)
// lines to draw on canvas
val lines = listOf<String>(
"I am first line.",
"This is second line.",
"It is another line.",
"Last line."
)
// draw multiline text on canvas and get bitmap
val bitmap = drawMultilineText(
lines = lines,
initialY = 225F,
textSize = 110F,
textColor = Color.parseColor("#333399"),
canvasColor = Color.parseColor("#A2A2D0")
)
// show drawing on image view
imageView.setImageBitmap(bitmap)
}
}
// function to draw multiline text on canvas
fun drawMultilineText(
lines:List<String> = listOf(),
initialY:Float = 200F,
textColor:Int = Color.BLACK,
textSize:Float = 120F,
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
// set typeface with style
typeface = Typeface.create(
Typeface.SANS_SERIF,Typeface.NORMAL)
// important to align text horizontally center
textAlign = Paint.Align.CENTER
}
// calculate canvas horizontal center
val x = canvas.width / 2F
// initial canvas y position to draw text
var y = initialY
// finally, draw the lines on canvas center
lines.forEach {
canvas.drawText(
it, // text to draw
x, // x-coordinate of the origin of the text being drawn
y, // y-coordinate of the baseline of the text being drawn
paint // paint used for the text e.g. color, size, style
)
// calculate next line y position
y += paint.descent() - paint.ascent()
}
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" />
</androidx.constraintlayout.widget.ConstraintLayout>
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