Redraw immediately on resize and window start

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

@@ -33,7 +33,7 @@ open class SkiaLayer : HardwareLayer() {
         super.init()
         redrawer = platformOperations.createRedrawer(this)
         redrawer?.syncSize()
-        needRedraw()
+        redrawer?.redrawImmediately()
     }
 
     override fun dispose() {
@@ -49,7 +49,7 @@ open class SkiaLayer : HardwareLayer() {
     override fun setBounds(x: Int, y: Int, width: Int, height: Int) {
         super.setBounds(x, y, width, height)
         redrawer?.syncSize()
-        needRedraw()
+        redrawer?.redrawImmediately()
     }
 
     override fun paint(g: Graphics) {

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

@@ -12,10 +12,7 @@ internal class LinuxRedrawer(
     private val layer: HardwareLayer
 ) : Redrawer {
     private val context = layer.lockDrawingSurface {
-        val context = it.createContext()
-        it.makeCurrent(context)
-        it.setSwapInterval(if (SkikoProperties.vsyncEnabled) 1 else 0)
-        context
+        it.createContext()
     }
     private var isDisposed = false
 
@@ -33,6 +30,16 @@ internal class LinuxRedrawer(
         frameDispatcher.scheduleFrame()
     }
 
+    override fun redrawImmediately() = layer.lockDrawingSurface {
+        check(!isDisposed)
+        update(System.nanoTime())
+        it.makeCurrent(context)
+        draw()
+        it.setSwapInterval(0)
+        it.swapBuffers()
+        OpenGLApi.instance.glFinish()
+    }
+
     private fun update(nanoTime: Long) {
         layer.update(nanoTime)
     }
@@ -69,6 +76,8 @@ internal class LinuxRedrawer(
                 }
 
                 toRedrawAlive.forEachIndexed { index, _ ->
+                    // it is ok to set swap interval every frame, there is no performance overhead
+                    drawingSurfaces[index].setSwapInterval(if (SkikoProperties.vsyncEnabled) 1 else 0)
                     drawingSurfaces[index].swapBuffers()
                 }
 

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

@@ -104,6 +104,11 @@ internal class MacOsRedrawer(
     override fun needRedraw() {
         frameDispatcher.scheduleFrame()
     }
+
+    override fun redrawImmediately() {
+        layer.update(System.nanoTime())
+        drawLayer.setNeedsDisplay()
+    }
 }
 
 private open class AWTGLLayer(private val containerPtr: Long, setNeedsDisplayOnBoundsChange: Boolean) {

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

@@ -3,5 +3,6 @@ package org.jetbrains.skiko.redrawer
 interface Redrawer {
     fun dispose()
     fun needRedraw()
+    fun redrawImmediately()
     fun syncSize() = Unit
 }
\ No newline at end of file

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

@@ -37,6 +37,15 @@ internal class WindowsRedrawer(
         frameDispatcher.scheduleFrame()
     }
 
+    override fun redrawImmediately() {
+        check(!isDisposed)
+        update(System.nanoTime())
+        makeCurrent()
+        draw()
+        swapBuffers()
+        OpenGLApi.instance.glFinish()
+    }
+
     private fun update(nanoTime: Long) {
         layer.update(nanoTime)
     }