From 798666376c953723db8e978e32abf183d2fab5d2 Mon Sep 17 00:00:00 2001
From: Sebastiano Poggi <sebp@google.com>
Date: Fri, 22 Sep 2023 13:48:57 +0200
Subject: [PATCH] Use new Swing rendering pipeline by default

---
 README.md                                     | 16 ++++++++++++++++
 .../jewel/foundation/Compatibility.kt         | 19 +++++++++++++++++++
 ...omposePanel.kt => ToolWindowExtensions.kt} |  5 +++++
 3 files changed, 40 insertions(+)
 create mode 100644 core/src/main/kotlin/org/jetbrains/jewel/foundation/Compatibility.kt
 rename ide-laf-bridge/src/main/kotlin/org/jetbrains/jewel/bridge/{ComposePanel.kt => ToolWindowExtensions.kt} (71%)

diff --git a/README.md b/README.md
index 7751795cd0..7beeb8f683 100644
--- a/README.md
+++ b/README.md
@@ -69,7 +69,23 @@ val svgLoader = service<SwingBridgeService>().svgLoader
 val painterProvider = retrieveStatelessIcon("icons/bot-toolwindow.svg", svgLoader, iconData)
 ```
 
+#### Swing interoperability
+
+As this is Compose for Desktop, you get a good degree of interoperability with Swing. To avoid glitches and z-order
+issues, you should enable the
+[experimental Swing rendering pipeline](https://blog.jetbrains.com/kotlin/2023/08/compose-multiplatform-1-5-0-release/#enhanced-swing-interop)
+before you initialize Compose content.
+
+The `ToolWindow.addComposeTab()` extension function provided by the `ide-laf-bridge` module will take care of that for
+you, but if you want to also enable it in other scenarios and in standalone applications, you can call the
+`enableNewSwingCompositing()` function in your Compose entry points (that is, right before creating a `ComposePanel`).
+
+> [!NOTE]
+> The new Swing rendering pipeline is experimental and may have performance repercussions, especially on Windows, where
+> HW acceleration is not yet available.
+
 ### Need help?
+
 You can find help on the [`#jewel`](https://app.slack.com/client/T09229ZC6/C05T8U2C31T) channel on the Kotlin Slack.
 If you don't already have access to the Kotlin Slack, you can request it
 [here](https://surveys.jetbrains.com/s3/kotlin-slack-sign-up).
diff --git a/core/src/main/kotlin/org/jetbrains/jewel/foundation/Compatibility.kt b/core/src/main/kotlin/org/jetbrains/jewel/foundation/Compatibility.kt
new file mode 100644
index 0000000000..02f930604f
--- /dev/null
+++ b/core/src/main/kotlin/org/jetbrains/jewel/foundation/Compatibility.kt
@@ -0,0 +1,19 @@
+package org.jetbrains.jewel.foundation
+
+import org.jetbrains.jewel.ExperimentalJewelApi
+
+/**
+ * Enables the new compositing strategy for rendering directly into Swing
+ * Graphics. This fixes z-order problems and artifacts on resizing, but
+ * has a performance penalty on Windows (as of 1.5.1) because there is no
+ * DirectX HW acceleration. Linux and macOS have HW acceleration though.
+ *
+ * We assume the majority of our users will want this flag to be on, so
+ * this convenience function is provided to that end. Make sure you call
+ * it **before** you initialize any Compose content. The function is
+ * idempotent and extremely cheap, so you can call it on any entry point.
+ */
+@ExperimentalJewelApi
+fun enableNewSwingCompositing() {
+    System.setProperty("compose.swing.render.on.graphics", "true")
+}
diff --git a/ide-laf-bridge/src/main/kotlin/org/jetbrains/jewel/bridge/ComposePanel.kt b/ide-laf-bridge/src/main/kotlin/org/jetbrains/jewel/bridge/ToolWindowExtensions.kt
similarity index 71%
rename from ide-laf-bridge/src/main/kotlin/org/jetbrains/jewel/bridge/ComposePanel.kt
rename to ide-laf-bridge/src/main/kotlin/org/jetbrains/jewel/bridge/ToolWindowExtensions.kt
index 09c28ff10f..4e192def5b 100644
--- a/ide-laf-bridge/src/main/kotlin/org/jetbrains/jewel/bridge/ComposePanel.kt
+++ b/ide-laf-bridge/src/main/kotlin/org/jetbrains/jewel/bridge/ToolWindowExtensions.kt
@@ -3,6 +3,7 @@ package org.jetbrains.jewel.bridge
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.awt.ComposePanel
 import com.intellij.openapi.wm.ToolWindow
+import org.jetbrains.jewel.foundation.enableNewSwingCompositing
 
 fun ToolWindow.addComposeTab(
     tabDisplayName: String,
@@ -10,6 +11,10 @@ fun ToolWindow.addComposeTab(
     isCloseable: Boolean = false,
     content: @Composable () -> Unit,
 ) {
+    // We need to make sure this is done before Compose is attached.
+    // The operation is idempotent, so we can safely do it every time.
+    enableNewSwingCompositing()
+
     val composePanel = ComposePanel()
     composePanel.setContent(content)
     val tabContent = contentManager.factory.createContent(composePanel, tabDisplayName, isLockable)