Register default renderer for BufferedImage

Fixes #292

Author: ileasile

jupyter-lib/api/src/main/kotlin/org/jetbrains/kotlinx/jupyter/api/defaultRenderers.kt

@@ -0,0 +1,19 @@
+package org.jetbrains.kotlinx.jupyter.api
+
+import java.awt.image.BufferedImage
+import java.io.ByteArrayOutputStream
+import java.util.Base64
+import javax.imageio.ImageIO
+
+val bufferedImageRenderer = createRenderer<BufferedImage> {
+    val format = "png"
+    val stream = ByteArrayOutputStream()
+    ImageIO.write(it, format, stream)
+    val data = stream.toByteArray()
+    val encoder = Base64.getEncoder()
+    val src = buildString {
+        append("""data:image/$format;base64,""")
+        append(encoder.encodeToString(data))
+    }
+    HTML("""<img src="$src"/>""")
+}

jupyter-lib/api/src/main/kotlin/org/jetbrains/kotlinx/jupyter/api/renderersHandling.kt

@@ -142,3 +142,9 @@ class SubtypeRendererTypeHandler(private val superType: KClass<*>, override val
         return SubtypeRendererTypeHandler(superType, execution.replaceVariables(mapping))
     }
 }
+
+inline fun <reified T : Any> createRenderer(crossinline renderAction: (T) -> Any?): RendererTypeHandler {
+    return SubtypeRendererTypeHandler(T::class) { _, result ->
+        FieldValue(renderAction(result.value as T), result.name)
+    }
+}

src/main/kotlin/org/jetbrains/kotlinx/jupyter/protocol.kt

@@ -13,9 +13,9 @@ import org.jetbrains.kotlinx.jupyter.LoggingManagement.disableLogging
 import org.jetbrains.kotlinx.jupyter.LoggingManagement.mainLoggerLevel
 import org.jetbrains.kotlinx.jupyter.api.DisplayResult
 import org.jetbrains.kotlinx.jupyter.api.KotlinKernelVersion.Companion.toMaybeUnspecifiedString
-import org.jetbrains.kotlinx.jupyter.api.MutableJsonObject
 import org.jetbrains.kotlinx.jupyter.api.Notebook
 import org.jetbrains.kotlinx.jupyter.api.Renderable
+import org.jetbrains.kotlinx.jupyter.api.libraries.ExecutionHost
 import org.jetbrains.kotlinx.jupyter.api.setDisplayId
 import org.jetbrains.kotlinx.jupyter.api.textResult
 import org.jetbrains.kotlinx.jupyter.common.looksLikeReplCommand
@@ -104,17 +104,22 @@ class OkResponseWithMessage(
 }
 
 interface DisplayHandler {
-    fun handleDisplay(value: Any)
-    fun handleUpdate(value: Any, id: String? = null)
+    fun handleDisplay(value: Any, host: ExecutionHost)
+    fun handleUpdate(value: Any, host: ExecutionHost, id: String? = null)
 }
 
 class SocketDisplayHandler(
     private val socket: JupyterConnection.Socket,
     private val notebook: NotebookImpl,
     private val message: Message,
 ) : DisplayHandler {
-    override fun handleDisplay(value: Any) {
-        val display = value.toDisplayResult(notebook) ?: return
+    private fun render(host: ExecutionHost, value: Any): DisplayResult? {
+        val renderedValue = notebook.renderersProcessor.renderValue(host, value)
+        return renderedValue.toDisplayResult(notebook)
+    }
+
+    override fun handleDisplay(value: Any, host: ExecutionHost) {
+        val display = render(host, value) ?: return
         val json = display.toJson()
 
         notebook.currentCell?.addDisplay(display)
@@ -132,9 +137,9 @@ class SocketDisplayHandler(
         )
     }
 
-    override fun handleUpdate(value: Any, id: String?) {
-        val display = value.toDisplayResult(notebook) ?: return
-        val json: MutableJsonObject = display.toJson().toMutableMap()
+    override fun handleUpdate(value: Any, host: ExecutionHost, id: String?) {
+        val display = render(host, value) ?: return
+        val json = display.toJson().toMutableMap()
 
         notebook.currentCell?.displays?.update(id, display)
 

src/main/kotlin/org/jetbrains/kotlinx/jupyter/repl.kt

@@ -313,6 +313,7 @@ class ReplForJupyterImpl(
 
     private val renderersProcessor: ResultsRenderersProcessor = run {
         val processor = RenderersProcessorImpl(contextUpdater)
+        processor.registerDefaultRenderers()
         notebook.typeRenderersProcessor = processor
         processor
     }

src/main/kotlin/org/jetbrains/kotlinx/jupyter/repl/impl/CellExecutorImpl.kt

@@ -134,7 +134,7 @@ internal class CellExecutorImpl(private val replContext: SharedReplContext) : Ce
             rethrowAsLibraryException(LibraryProblemPart.RESOURCES) {
                 library.resources.forEach {
                     val htmlText = sharedContext.resourcesProcessor.wrapLibrary(it, classLoader)
-                    displayHandler?.handleDisplay(HTML(htmlText))
+                    displayHandler?.handleDisplay(HTML(htmlText), this)
                 }
             }
 
@@ -145,11 +145,11 @@ internal class CellExecutorImpl(private val replContext: SharedReplContext) : Ce
         override fun execute(code: Code) = executor.execute(code, displayHandler, processVariables = false, invokeAfterCallbacks = false).result
 
         override fun display(value: Any) {
-            displayHandler?.handleDisplay(value)
+            displayHandler?.handleDisplay(value, this)
         }
 
         override fun updateDisplay(value: Any, id: String?) {
-            displayHandler?.handleUpdate(value, id)
+            displayHandler?.handleUpdate(value, this, id)
         }
 
         override fun scheduleExecution(execution: ExecutionCallback<*>) {

src/main/kotlin/org/jetbrains/kotlinx/jupyter/util.kt

@@ -1,5 +1,7 @@
 package org.jetbrains.kotlinx.jupyter
 
+import org.jetbrains.kotlinx.jupyter.api.bufferedImageRenderer
+import org.jetbrains.kotlinx.jupyter.codegen.ResultsRenderersProcessor
 import org.jetbrains.kotlinx.jupyter.compiler.util.SourceCodeImpl
 import kotlin.script.experimental.api.ScriptDiagnostic
 import kotlin.script.experimental.api.SourceCode
@@ -62,3 +64,7 @@ fun Int.toSourceCodePositionWithNewAbsolute(code: SourceCode, newCode: SourceCod
 
     return SourceCode.Position(pos.line, abs - absLineStart + 1, abs)
 }
+
+fun ResultsRenderersProcessor.registerDefaultRenderers() {
+    register(bufferedImageRenderer)
+}

src/test/kotlin/org/jetbrains/kotlinx/jupyter/test/testUtil.kt

@@ -13,6 +13,7 @@ import org.jetbrains.kotlinx.jupyter.api.JREInfoProvider
 import org.jetbrains.kotlinx.jupyter.api.KotlinKernelVersion
 import org.jetbrains.kotlinx.jupyter.api.Notebook
 import org.jetbrains.kotlinx.jupyter.api.RenderersProcessor
+import org.jetbrains.kotlinx.jupyter.api.libraries.ExecutionHost
 import org.jetbrains.kotlinx.jupyter.api.libraries.JupyterIntegration
 import org.jetbrains.kotlinx.jupyter.api.libraries.LibraryDefinition
 import org.jetbrains.kotlinx.jupyter.config.defaultRepositories
@@ -132,11 +133,11 @@ class InMemoryLibraryResolver(
 }
 
 class TestDisplayHandler(val list: MutableList<Any> = mutableListOf()) : DisplayHandler {
-    override fun handleDisplay(value: Any) {
+    override fun handleDisplay(value: Any, host: ExecutionHost) {
         list.add(value)
     }
 
-    override fun handleUpdate(value: Any, id: String?) {
+    override fun handleUpdate(value: Any, host: ExecutionHost, id: String?) {
         // TODO: Implement correct updating
     }
 }