From c1621f62b009b97ac5948ebf6237e3a38066ac2c Mon Sep 17 00:00:00 2001
From: Igor Demin <igordmn@gmail.com>
Date: Tue, 8 Feb 2022 15:27:41 +0300
Subject: [PATCH] Draw the first frame before window is visible

Fixes https://github.com/JetBrains/compose-jb/issues/1794

If the first frame is too long to draw (> 500ms), users should make their apps asynchronous and draw UI gradully in multiple frames without blocking the UI thread for too long in single frame

# Conflicts:
#	compose/ui/ui/src/desktopTest/kotlin/androidx/compose/ui/window/TestUtils.kt
#	compose/ui/ui/src/desktopTest/kotlin/androidx/compose/ui/window/dialog/DialogTest.kt
#	compose/ui/ui/src/desktopTest/kotlin/androidx/compose/ui/window/window/WindowTest.kt
---
 .../compose/ui/window/dialog/DialogTest.kt    | 31 +++++++++++++++++++
 .../compose/ui/window/window/WindowTest.kt    | 30 ++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/compose/ui/ui/src/desktopTest/kotlin/androidx/compose/ui/window/dialog/DialogTest.kt b/compose/ui/ui/src/desktopTest/kotlin/androidx/compose/ui/window/dialog/DialogTest.kt
index 7f1f30f279a2f..5380a00e83df9 100644
--- a/compose/ui/ui/src/desktopTest/kotlin/androidx/compose/ui/window/dialog/DialogTest.kt
+++ b/compose/ui/ui/src/desktopTest/kotlin/androidx/compose/ui/window/dialog/DialogTest.kt
@@ -552,4 +552,35 @@ class DialogTest {
 
         exitApplication()
     }
+
+
+    @Test(timeout = 30000)
+    fun `should draw before dialog is visible`() = runApplicationTest {
+        var isComposed = false
+        var isDrawn = false
+        var isVisibleOnFirstComposition = false
+        var isVisibleOnFirstDraw = false
+
+        launchTestApplication {
+            Dialog(onCloseRequest = ::exitApplication) {
+                if (!isComposed) {
+                    isVisibleOnFirstComposition = window.isVisible
+                    isComposed = true
+                }
+
+                Canvas(Modifier.fillMaxSize()) {
+                    if (!isDrawn) {
+                        isVisibleOnFirstDraw = window.isVisible
+                        isDrawn = true
+                    }
+                }
+            }
+        }
+
+        awaitIdle()
+        assertThat(isVisibleOnFirstComposition).isFalse()
+        assertThat(isVisibleOnFirstDraw).isFalse()
+
+        exitTestApplication()
+    }
 }
\ No newline at end of file
diff --git a/compose/ui/ui/src/desktopTest/kotlin/androidx/compose/ui/window/window/WindowTest.kt b/compose/ui/ui/src/desktopTest/kotlin/androidx/compose/ui/window/window/WindowTest.kt
index 315e3620dbfa0..9fdf112748fc6 100644
--- a/compose/ui/ui/src/desktopTest/kotlin/androidx/compose/ui/window/window/WindowTest.kt
+++ b/compose/ui/ui/src/desktopTest/kotlin/androidx/compose/ui/window/window/WindowTest.kt
@@ -558,4 +558,34 @@ class WindowTest {
         assertThat(isApplicationEffectEnded).isTrue()
         assertThat(isWindowEffectEnded).isTrue()
     }
+
+    @Test(timeout = 30000)
+    fun `should draw before window is visible`() = runApplicationTest {
+        var isComposed = false
+        var isDrawn = false
+        var isVisibleOnFirstComposition = false
+        var isVisibleOnFirstDraw = false
+
+        launchTestApplication {
+            Window(onCloseRequest = ::exitApplication) {
+                if (!isComposed) {
+                    isVisibleOnFirstComposition = window.isVisible
+                    isComposed = true
+                }
+
+                Canvas(Modifier.fillMaxSize()) {
+                    if (!isDrawn) {
+                        isVisibleOnFirstDraw = window.isVisible
+                        isDrawn = true
+                    }
+                }
+            }
+        }
+
+        awaitIdle()
+        assertThat(isVisibleOnFirstComposition).isFalse()
+        assertThat(isVisibleOnFirstDraw).isFalse()
+
+        exitTestApplication()
+    }
 }
\ No newline at end of file