Bitmaps in Java2D

The Java2D backend supports loading bitmap images and converting them to pictures, and converting pictures to bitmaps.

Loading Bitmaps

Loading bitmap images from disk and converting them to pictures works as described in the section on bitmaps. Specifically, bitmaps can be loaded as instances of BufferedImage from a File or a Path. The implementation uses ImageIO, and hence supports all the bitmap formats that ImageIO supports. The example below shows how this works.

import doodle.syntax.all.*
import doodle.java2d.{*, given}

import java.io.File
import java.nio.file.Paths

File("/path/to/bitmap.png").loadBitmap
Paths.get("/path/to/bitmap.png").loadBitmap

Converting Bitmaps to Pictures

A BufferedImage can also be converted to a Picture using the toPicture method. Instances of Base64 can also be converted to a Picture in the same way.

Converting Pictures to Bitmaps

A Picture can be converted to a bitmap either as a BufferedImage or as Base64 data.

Call the bufferedImage method to convert a Picture to a BufferedImage.

import cats.effect.unsafe.implicits.global
import doodle.syntax.all.*
import doodle.java2d.{*, given}

val bitmap = Picture.circle(200).bufferedImage()

The following variants of bufferedImage are available:

• bufferedImage(), shown above, use a default Frame;
• bufferedImage(frame) allows you to specify a Frame; and
• bufferedImageToIO() and bufferedImageToIO(frame) work like bufferedImage but return an IO[BufferedImage] instead of a BufferedImage.

Use the base64 method to convert a Picture to Base64 encoded data. You will need to specify a Format as a type parameter, which determines the bitmap format that is used. The example below shows encoding a Picture as a PNG.

import cats.effect.unsafe.implicits.global
import doodle.core.format.Png
import doodle.syntax.all.*
import doodle.java2d.{*, given}

val base64 = Picture.circle(200).base64[Png]()

The following method variants are available:

• base64[Format](frame) to specify a Frame to use instead of the default; and
• base64ToIO[Format]() and base64[Format](frame) to return a IO[Base64[Format]].