Set background color for DirectX swap chain buffers.

skiko/src/jvmMain/cpp/windows/directXRedrawer.cc

@@ -299,6 +299,9 @@ HRESULT D3DCompile(
 
         gr_cp<IDXGISwapChain1> swapChain;
         GR_D3D_CALL_ERRCHECK(swapChainFactory->CreateSwapChainForHwnd(d3dDevice->queue.get(), fWindow, &swapChainDesc, &swapChainFSDesc, nullptr, &swapChain));
+        DXGI_RGBA background = {1.0f, 1.0f, 1.0f, 1.0f};
+        swapChain->SetBackgroundColor(&background);
+
         GR_D3D_CALL_ERRCHECK(swapChain->QueryInterface(IID_PPV_ARGS(&d3dDevice->swapChain)));
         GR_D3D_CALL_ERRCHECK(d3dDevice->device->CreateFence(0, D3D12_FENCE_FLAG_NONE, IID_PPV_ARGS(&d3dDevice->fence)));
         d3dDevice->fenceEvent = CreateEvent(nullptr, FALSE, FALSE, nullptr);

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/SkiaLayer.kt

@@ -45,7 +45,7 @@ open class SkiaLayer(
         contextHandler = createContextHandler(this, initialRenderApi)
         redrawer = platformOperations.createRedrawer(this, initialRenderApi, properties)
         redrawer?.syncSize()
-        redrawer?.redrawImmediately()
+        draw(isBlank = true)
     }
 
     override fun dispose() {
@@ -109,22 +109,26 @@ open class SkiaLayer(
         }
     }
 
-    override fun draw() {
+    override fun draw() = draw(isBlank = false)
+
+    fun draw(isBlank: Boolean) {
         check(!isDisposed)
         contextHandler?.apply {
             if (!initContext()) {
                 fallbackToNextApi()
                 return
             }
-            initCanvas()
-            clearCanvas()
-            synchronized(pictureLock) {
-                val picture = picture
-                if (picture != null) {
-                    drawOnCanvas(picture.instance)
+            if (!isBlank) {
+                initCanvas()
+                clearCanvas()
+                synchronized(pictureLock) {
+                    val picture = picture
+                    if (picture != null) {
+                        drawOnCanvas(picture.instance)
+                    }
                 }
+                flush()
             }
-            flush()
         }
     }
 
@@ -145,6 +149,7 @@ open class SkiaLayer(
     private fun fallbackToNextApi() {
         val nextApi = fallbackRenderApiQueue.removeAt(0)
         println("Falling back to $nextApi rendering...")
+        contextHandler?.dispose()
         redrawer?.dispose()
         contextHandler = createContextHandler(this, nextApi)
         redrawer = platformOperations.createRedrawer(this, nextApi, properties)

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/context/Direct3DContextHandler.kt

@@ -24,6 +24,10 @@ internal class Direct3DContextHandler(layer: SkiaLayer) : ContextHandler(layer)
                 if (device == 0L) {
                     throw Exception("Failed to create DirectX12 device.")
                 }
+                val scale = layer.contentScale
+                val w = (layer.width * scale).toInt().coerceAtLeast(0)
+                val h = (layer.height * scale).toInt().coerceAtLeast(0)
+                directXRedrawer.resizeBuffers(device, w, h)
                 context = directXRedrawer.makeContext(device)
             }
         } catch (e: Exception) {

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/redrawer/Direct3DRedrawer.kt

@@ -66,6 +66,7 @@ internal class Direct3DRedrawer(
     external fun createDirectXDevice(windowHandle: Long): Long
     external fun makeDirectXContext(device: Long): Long
     external fun makeDirectXRenderTarget(device: Long, width: Int, height: Int): Long
+    external fun resizeBuffers(device: Long, width: Int, height: Int)
     private external fun finishFrame(device: Long, context: Long, surface: Long, isVsyncEnabled: Boolean)
     external fun disposeDevice(device: Long)
 }