Add option to downsize BufferedImage in HTML renderer

Introduced a configuration option to conditionally downsize BufferedImages in the HTML renderer. This mitigates potential memory problems by resizing images according to the provided DisplayConfiguration, specifically affecting the output of dataframes in the Kotlin Notebook plugin.

Author: ermolenkodev

core/generated-sources/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/html.kt

@@ -21,6 +21,7 @@ import org.jetbrains.kotlinx.dataframe.columns.ColumnWithPath
 import org.jetbrains.kotlinx.dataframe.columns.FrameColumn
 import org.jetbrains.kotlinx.dataframe.impl.DataFrameSize
 import org.jetbrains.kotlinx.dataframe.impl.columns.addPath
+import org.jetbrains.kotlinx.dataframe.impl.io.resizeKeepingAspectRatio
 import org.jetbrains.kotlinx.dataframe.impl.renderType
 import org.jetbrains.kotlinx.dataframe.impl.scale
 import org.jetbrains.kotlinx.dataframe.impl.truncate
@@ -31,6 +32,7 @@ import org.jetbrains.kotlinx.dataframe.name
 import org.jetbrains.kotlinx.dataframe.nrow
 import org.jetbrains.kotlinx.dataframe.size
 import java.awt.Desktop
+import java.awt.image.BufferedImage
 import java.io.File
 import java.io.InputStreamReader
 import java.net.URL
@@ -152,7 +154,8 @@ internal fun AnyFrame.toHtmlData(
                     DataFrameReference(id, value.size)
                 }
             } else {
-                val html = formatter.format(value, cellRenderer, renderConfig)
+                val html =
+                    formatter.format(downsizeBufferedImageIfNeeded(value, renderConfig), cellRenderer, renderConfig)
                 val style = renderConfig.cellFormatter?.invoke(FormattingDSL, it, col)?.attributes()?.ifEmpty { null }
                     ?.joinToString(";") { "${it.first}:${it.second}" }
                 HtmlContent(html, style)
@@ -180,6 +183,26 @@ internal fun AnyFrame.toHtmlData(
     return DataFrameHtmlData(style = "", body = body, script = script)
 }
 
+private const val DEFAULT_HTML_IMG_SIZE = 100
+
+/**
+ * This method resizes a BufferedImage if necessary, according to the provided DisplayConfiguration.
+ * It is essential to prevent potential memory problems when serializing HTML data for display in the Kotlin Notebook plugin.
+ *
+ * @param value The input value to be checked and possibly downsized.
+ * @param renderConfig The DisplayConfiguration to determine if downsizing is needed.
+ * @return The downsized BufferedImage if value is a BufferedImage and downsizing is enabled in the DisplayConfiguration,
+ *         otherwise returns the input value unchanged.
+ */
+private fun downsizeBufferedImageIfNeeded(value: Any?, renderConfig: DisplayConfiguration): Any? =
+    when {
+        value is BufferedImage && renderConfig.downsizeBufferedImage -> {
+            value.resizeKeepingAspectRatio(DEFAULT_HTML_IMG_SIZE)
+        }
+
+        else -> value
+    }
+
 /**
  * Renders [this] [DataFrame] as static HTML (meaning no JS is used).
  * CSS rendering is enabled by default but can be turned off using [includeCss]
@@ -568,6 +591,7 @@ public data class DisplayConfiguration(
     internal val localTesting: Boolean = flagFromEnv("KOTLIN_DATAFRAME_LOCAL_TESTING"),
     var useDarkColorScheme: Boolean = false,
     var enableFallbackStaticTables: Boolean = true,
+    var downsizeBufferedImage: Boolean = true
 ) {
     public companion object {
         public val DEFAULT: DisplayConfiguration = DisplayConfiguration()

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/html.kt

@@ -21,6 +21,7 @@ import org.jetbrains.kotlinx.dataframe.columns.ColumnWithPath
 import org.jetbrains.kotlinx.dataframe.columns.FrameColumn
 import org.jetbrains.kotlinx.dataframe.impl.DataFrameSize
 import org.jetbrains.kotlinx.dataframe.impl.columns.addPath
+import org.jetbrains.kotlinx.dataframe.impl.io.resizeKeepingAspectRatio
 import org.jetbrains.kotlinx.dataframe.impl.renderType
 import org.jetbrains.kotlinx.dataframe.impl.scale
 import org.jetbrains.kotlinx.dataframe.impl.truncate
@@ -31,6 +32,7 @@ import org.jetbrains.kotlinx.dataframe.name
 import org.jetbrains.kotlinx.dataframe.nrow
 import org.jetbrains.kotlinx.dataframe.size
 import java.awt.Desktop
+import java.awt.image.BufferedImage
 import java.io.File
 import java.io.InputStreamReader
 import java.net.URL
@@ -152,7 +154,8 @@ internal fun AnyFrame.toHtmlData(
                     DataFrameReference(id, value.size)
                 }
             } else {
-                val html = formatter.format(value, cellRenderer, renderConfig)
+                val html =
+                    formatter.format(downsizeBufferedImageIfNeeded(value, renderConfig), cellRenderer, renderConfig)
                 val style = renderConfig.cellFormatter?.invoke(FormattingDSL, it, col)?.attributes()?.ifEmpty { null }
                     ?.joinToString(";") { "${it.first}:${it.second}" }
                 HtmlContent(html, style)
@@ -180,6 +183,26 @@ internal fun AnyFrame.toHtmlData(
     return DataFrameHtmlData(style = "", body = body, script = script)
 }
 
+private const val DEFAULT_HTML_IMG_SIZE = 100
+
+/**
+ * This method resizes a BufferedImage if necessary, according to the provided DisplayConfiguration.
+ * It is essential to prevent potential memory problems when serializing HTML data for display in the Kotlin Notebook plugin.
+ *
+ * @param value The input value to be checked and possibly downsized.
+ * @param renderConfig The DisplayConfiguration to determine if downsizing is needed.
+ * @return The downsized BufferedImage if value is a BufferedImage and downsizing is enabled in the DisplayConfiguration,
+ *         otherwise returns the input value unchanged.
+ */
+private fun downsizeBufferedImageIfNeeded(value: Any?, renderConfig: DisplayConfiguration): Any? =
+    when {
+        value is BufferedImage && renderConfig.downsizeBufferedImage -> {
+            value.resizeKeepingAspectRatio(DEFAULT_HTML_IMG_SIZE)
+        }
+
+        else -> value
+    }
+
 /**
  * Renders [this] [DataFrame] as static HTML (meaning no JS is used).
  * CSS rendering is enabled by default but can be turned off using [includeCss]
@@ -568,6 +591,7 @@ public data class DisplayConfiguration(
     internal val localTesting: Boolean = flagFromEnv("KOTLIN_DATAFRAME_LOCAL_TESTING"),
     var useDarkColorScheme: Boolean = false,
     var enableFallbackStaticTables: Boolean = true,
+    var downsizeBufferedImage: Boolean = true
 ) {
     public companion object {
         public val DEFAULT: DisplayConfiguration = DisplayConfiguration()