Add Playdate Image (PDI) support

README.md

@@ -21,7 +21,7 @@ To know more about the library and how to get started check the [microsite](http
 * Keyboard and pointer input
 * Surface blitting (with multiple blending modes)
 * Surface views and infinite planes
-* Reading and Writing PPM, BMP and QOI images
+* Reading and Writing PPM, BMP, QOI and PDI images
 * Audio playback (mono)
 * Procedural audio generation
 * Reading and Writing RTTL, WAV, AIFF and QOA sound files

docs/_docs/overview.md

@@ -45,7 +45,7 @@ Not only is mouse input supported, but touch screen input also comes for free.
 
 A `Resource` abstraction provides a backend-agnostic way to load and store resources.
 
-Codecs for some image formats (PPM, BMP and QOI) is also included.
+Codecs for some image formats (PPM, BMP, QOI and PDI) are also included. The same is true for some audio formats (RTTL, WAV, AIFF and QOA).
 
 ## Minart runtime and other runtimes
 

image/shared/src/main/scala/eu/joaocosta/minart/graphics/image/Image.scala

@@ -35,6 +35,11 @@ object Image {
   def loadQoiImage(resource: Resource): Try[RamSurface] =
     loadImage(qoi.QoiImageFormat.defaultFormat, resource)
 
+  /** Loads an image in the PDI format.
+    */
+  def loadPdiImage(resource: Resource): Try[RamSurface] =
+    loadImage(pdi.PdiImageFormat.defaultFormat, resource)
+
   /** Stores an image using a custom ImageWriter.
     *
     * @param writer ImageWriter to use
@@ -63,4 +68,9 @@ object Image {
   def storeQoiImage(surface: Surface, resource: Resource): Try[Unit] =
     storeImage(qoi.QoiImageFormat.defaultFormat, surface, resource)
 
+  /** Stores an image in the PDI format.
+    */
+  def storePdiImage(surface: Surface, resource: Resource): Try[Unit] =
+    storeImage(pdi.PdiImageFormat.defaultFormat, surface, resource)
+
 }

image/shared/src/main/scala/eu/joaocosta/minart/graphics/image/pdi/CellHeader.scala

@@ -0,0 +1,12 @@
+package eu.joaocosta.minart.graphics.image.pdi
+
+private[pdi] final case class CellHeader(
+    clipWidth: Int,
+    clipHeight: Int,
+    stride: Int,
+    clipLeft: Int,
+    clipRight: Int,
+    clipTop: Int,
+    clipBottom: Int,
+    transparency: Boolean
+)

image/shared/src/main/scala/eu/joaocosta/minart/graphics/image/pdi/Header.scala

@@ -0,0 +1,6 @@
+package eu.joaocosta.minart.graphics.image.pdi
+
+private[pdi] final case class Header(
+    magic: String,
+    compressed: Boolean
+)

image/shared/src/main/scala/eu/joaocosta/minart/graphics/image/pdi/PdiImageFormat.scala

@@ -0,0 +1,13 @@
+package eu.joaocosta.minart.graphics.image.pdi
+
+/** Image reader and writer for PDI files.
+  *
+  * Supports reading and writing uncompressed Playdate PDIs.
+  */
+final class PdiImageFormat() extends PdiImageReader with PdiImageWriter
+
+object PdiImageFormat {
+  val defaultFormat = new PdiImageFormat()
+
+  val supportedFormats = Set("Playdate IMG")
+}

image/shared/src/main/scala/eu/joaocosta/minart/graphics/image/pdi/PdiImageReader.scala

@@ -0,0 +1,101 @@
+package eu.joaocosta.minart.graphics.image.pdi
+
+import java.io.InputStream
+
+import scala.annotation.tailrec
+
+import eu.joaocosta.minart.graphics.*
+import eu.joaocosta.minart.graphics.image.*
+import eu.joaocosta.minart.internal.*
+
+/** Image reader for PDI files.
+  *
+  * Supports uncompressed Playdate PDIs.
+  */
+trait PdiImageReader extends ImageReader {
+  import ByteReader.*
+
+  private def bitsFromByte(byte: Byte, entries: Int): List[Boolean] =
+    if (entries > 0) {
+      val colorBit = (byte & 0x80) >> 7
+      (colorBit == 1) :: bitsFromByte(((byte << 1) & 0xff).toByte, entries - 1)
+    } else Nil
+
+  private def loadBitLine(
+      data: CustomInputStream,
+      width: Int,
+      lineBytes: Int
+  ): ParseResult[Array[Boolean]] = {
+    readBytes(lineBytes).map(_.flatMap(b => bitsFromByte(b.toByte, 8)).take(width)).run(data)
+  }
+
+  @tailrec
+  private def loadBits(
+      data: CustomInputStream,
+      remainingLines: Int,
+      width: Int,
+      lineBytes: Int,
+      acc: Vector[Array[Boolean]] = Vector()
+  ): ParseResult[Vector[Array[Boolean]]] = {
+    if (isEmpty(data) || remainingLines == 0) Right(data -> acc)
+    else {
+      loadBitLine(data, width, lineBytes) match {
+        case Left(error) => Left(error)
+        case Right((remaining, line)) =>
+          loadBits(remaining, remainingLines - 1, width, lineBytes, acc :+ line)
+      }
+    }
+  }
+
+  private def loadHeader(bytes: CustomInputStream): ParseResult[Header] = {
+    (for {
+      magic <- readString(12).validate(
+        PdiImageFormat.supportedFormats,
+        m => s"Unsupported format: $m."
+      )
+      flags       <- readLENumber(4)
+      compression <- State.cond((flags & 0x80000000) == 0, false, "Unsuported compression")
+      header = Header(magic, compression)
+    } yield header).run(bytes)
+  }
+
+  private def loadCellHeader(bytes: CustomInputStream): ParseResult[CellHeader] = {
+    (for {
+      clipWidth  <- readLENumber(2)
+      clipHeight <- readLENumber(2)
+      cellStride <- readLENumber(2)
+      clipLeft   <- readLENumber(2)
+      clipRight  <- readLENumber(2)
+      clipTop    <- readLENumber(2)
+      clipBottom <- readLENumber(2)
+      flags      <- readLENumber(2)
+      transparency = (flags & 0x0003) != 0
+      header = CellHeader(clipWidth, clipHeight, cellStride, clipLeft, clipRight, clipTop, clipBottom, transparency)
+    } yield header).run(bytes)
+  }
+
+  final def loadImage(is: InputStream): Either[String, RamSurface] = {
+    val bytes = fromInputStream(is)
+    loadHeader(bytes).flatMap(_ => loadCellHeader(bytes)).flatMap { case (data, cellHeader) =>
+      val emptyColor = Color(0, 0, 0, 0)
+      val width      = cellHeader.clipLeft + cellHeader.clipWidth + cellHeader.clipRight
+      val leftPad    = Array.fill(cellHeader.clipLeft)(emptyColor)
+      val rightPad   = Array.fill(cellHeader.clipRight)(emptyColor)
+      for {
+        centerColors <- loadBits(data, cellHeader.clipHeight, cellHeader.clipWidth, cellHeader.stride)
+        centerMask   <- loadBits(data, cellHeader.clipHeight, cellHeader.clipWidth, cellHeader.stride)
+        centerPixels = centerColors._2.zip(centerMask._2).map { (colorLine, maskLine) =>
+          colorLine.zip(maskLine).map {
+            case (_, false)    => Color(0, 0, 0, 0)
+            case (false, true) => Color(0, 0, 0)
+            case (true, true)  => Color(255, 255, 255)
+          }
+        }
+        pixels =
+          Vector.fill(cellHeader.clipTop)(Array.fill(width)(emptyColor)) ++
+            centerPixels.map(center => leftPad ++ center ++ rightPad) ++
+            Vector.fill(cellHeader.clipBottom)(Array.fill(width)(emptyColor))
+      } yield (new RamSurface(pixels))
+    }
+  }
+}

image/shared/src/main/scala/eu/joaocosta/minart/graphics/image/pdi/PdiImageWriter.scala

@@ -0,0 +1,70 @@
+package eu.joaocosta.minart.graphics.image.pdi
+
+import java.io.OutputStream
+
+import scala.annotation.tailrec
+
+import eu.joaocosta.minart.graphics.*
+import eu.joaocosta.minart.graphics.image.*
+import eu.joaocosta.minart.internal.*
+
+/** Image writer for Pdi files.
+  *
+  * Stores data as uncompressed PlayDate PDIs.
+  */
+trait PdiImageWriter extends ImageWriter {
+  import ByteWriter.*
+
+  private def colorsToByte(acc: Byte, colors: List[Color], f: Color => Boolean): Byte = colors match {
+    case Nil => acc
+    case color :: rem =>
+      if (f(color)) colorsToByte(((acc << 1) | 0x01).toByte, rem, f)
+      else colorsToByte((acc << 1).toByte, rem, f)
+  }
+
+  private def lineToBytes(colors: List[Color], f: Color => Boolean): List[Byte] =
+    colors.sliding(8, 8).map(cs => colorsToByte(0.toByte, cs.padTo(8, Color(0, 0, 0, 0)), f)).toList
+
+  private def storeLine(colors: Array[Color], f: Color => Boolean): ByteStreamState[String] =
+    writeBytes(lineToBytes(colors.toList, f).map(java.lang.Byte.toUnsignedInt))
+
+  @tailrec
+  private def storePixels(
+      lines: Vector[Array[Color]],
+      f: Color => Boolean,
+      acc: ByteStreamState[String] = emptyStream
+  ): ByteStreamState[String] = {
+    if (lines.isEmpty) acc
+    else storePixels(lines.tail, f, acc.flatMap(_ => storeLine(lines.head, f)))
+  }
+
+  private val storeHeader: ByteStreamState[String] = {
+    (for {
+      _ <- writeString("Playdate IMG")
+      _ <- writeLENumber(0, 4) // Disable compression
+    } yield ())
+  }
+
+  private def storeCellHeader(surface: Surface): ByteStreamState[String] = {
+    (for {
+      _ <- writeLENumber(surface.width, 2)
+      _ <- writeLENumber(surface.height, 2)
+      _ <- writeLENumber(math.ceil(surface.width / 8.0).toInt, 2)
+      _ <- writeLENumber(0, 2)    // No padding
+      _ <- writeLENumber(0, 2)    // No padding
+      _ <- writeLENumber(0, 2)    // No padding
+      _ <- writeLENumber(0, 2)    // No padding
+      _ <- writeLENumber(0x03, 2) // Always enable transparency
+    } yield ())
+  }
+
+  final def storeImage(surface: Surface, os: OutputStream): Either[String, Unit] = {
+    val state = for {
+      _ <- storeHeader
+      _ <- storeCellHeader(surface)
+      _ <- storePixels(surface.getPixels(), color => math.max(math.max(color.r, color.g), color.b) >= 127)
+      _ <- storePixels(surface.getPixels(), color => color.a > 0)
+    } yield ()
+    toOutputStream(state, os)
+  }
+}

image/shared/src/test/scala/eu/joaocosta/minart/graphics/image/ImageReaderSpec.scala

@@ -80,6 +80,18 @@ class ImageReaderSpec extends munit.FunSuite {
       qoiTest("lausanne", 640, 480)
     }
 
+    test("Load a PDI image") {
+      def pdiTest(dir: String, width: Int, height: Int): Unit =
+        testSize(
+          List(
+            Image.loadPdiImage(Resource(s"$dir/pdi-2bit.pdi"))
+          ),
+          width,
+          height
+        )
+      pdiTest("alpha", 507, 200)
+    }
+
     test("Load the same data from different formats (square image)") {
       sameImage(
         List(

image/shared/src/test/scala/eu/joaocosta/minart/graphics/image/ImageWriterSpec.scala

@@ -36,5 +36,9 @@ class ImageWriterSpec extends munit.FunSuite {
       roundtripTest(Resource("scala-rect/qoi-24bit.qoi"), qoi.QoiImageFormat.defaultFormat)
       roundtripTest(Resource("lausanne/qoi-24bit.qoi"), qoi.QoiImageFormat.defaultFormat)
     }
+
+    test("Write a PDI image") {
+      roundtripTest(Resource("alpha/pdi-2bit.pdi"), pdi.PdiImageFormat.defaultFormat)
+    }
   }
 }