From c3a900847e861ebb847e13fb2a4b8ce6c454cdbd Mon Sep 17 00:00:00 2001
From: Igor Demin <igordmn@users.noreply.github.com>
Date: Wed, 6 Mar 2024 13:40:53 +0100
Subject: [PATCH] Windows. Fix a crash when we resize to zero and then to
 non-zero (#883)

Fixes https://github.com/JetBrains/compose-multiplatform/issues/4425

It is a regression after https://github.com/JetBrains/skiko/pull/858

The crash was because `d3dDevice->swapChain->GetBuffer` didn't return
the buffer to draw on if we reused the buffer from the previous frame
(we didn't change `surface` in case of zero size).

I am not completely sure why, but I exhausted my the investigation limit
and this fix is needed by other reasons (we need to wait for vsync).

## Testing
An additional check in the existed test (fails before the fix)
---
 .../jetbrains/skiko/context/Direct3DContextHandler.kt  | 10 +++++-----
 .../kotlin/org/jetbrains/skiko/SkiaLayerTest.kt        |  6 ++++++
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/skiko/src/awtMain/kotlin/org/jetbrains/skiko/context/Direct3DContextHandler.kt b/skiko/src/awtMain/kotlin/org/jetbrains/skiko/context/Direct3DContextHandler.kt
index 85ef216ef..d493a7278 100644
--- a/skiko/src/awtMain/kotlin/org/jetbrains/skiko/context/Direct3DContextHandler.kt
+++ b/skiko/src/awtMain/kotlin/org/jetbrains/skiko/context/Direct3DContextHandler.kt
@@ -45,12 +45,12 @@ internal class Direct3DContextHandler(layer: SkiaLayer) : JvmContextHandler(laye
     override fun initCanvas() {
         val context = context ?: return
         val scale = layer.contentScale
-        val width = (layer.width * scale).toInt()
-        val height = (layer.height * scale).toInt()
 
-        if (width <= 0 || height <= 0) {
-            return
-        }
+        // Direct3D can't work with zero size.
+        // Don't rewrite code to skipping, as we need the whole pipeline in zero case too
+        // (drawing -> flushing -> swapping -> waiting for vsync)
+        val width = (layer.width * scale).toInt().coerceAtLeast(1)
+        val height = (layer.height * scale).toInt().coerceAtLeast(1)
 
         if (isSizeChanged(width, height) || isSurfacesNull()) {
             disposeCanvas()
diff --git a/skiko/src/awtTest/kotlin/org/jetbrains/skiko/SkiaLayerTest.kt b/skiko/src/awtTest/kotlin/org/jetbrains/skiko/SkiaLayerTest.kt
index f0b9eaf42..1ba961e40 100644
--- a/skiko/src/awtTest/kotlin/org/jetbrains/skiko/SkiaLayerTest.kt
+++ b/skiko/src/awtTest/kotlin/org/jetbrains/skiko/SkiaLayerTest.kt
@@ -249,6 +249,12 @@ class SkiaLayerTest {
             layer.needRedraw()
             delay(1000)
             assertEquals(0, renderedWidth)
+
+            renderedWidth = -1
+            layer.size = Dimension(40, 40)
+            layer.needRedraw()
+            delay(1000)
+            assertEquals((40 * density).toInt(), renderedWidth)
         } finally {
             layer.dispose()
             window.close()