[sis] 02/02: Transfer of pixel data from Java2D image to JavaFX image should be scheduled to occur just before a JavaFX pulse. It seems to resolve the mysterious flickering effects that happened for so long.

[de...@apache.org]

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desruisseaux pushed a commit to branch geoapi-4.0
in repository https://gitbox.apache.org/repos/asf/sis.git

commit a55b18b3b32b16134662ece6aaa1761f969e99cd
Author: Martin Desruisseaux <ma...@geomatys.com>
AuthorDate: Sun Jul 10 21:11:30 2022 +0200

    Transfer of pixel data from Java2D image to JavaFX image should be scheduled to occur just before a JavaFX pulse.
    It seems to resolve the mysterious flickering effects that happened for so long.
---
 .../java/org/apache/sis/gui/map/MapCanvasAWT.java  | 26 ++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/application/sis-javafx/src/main/java/org/apache/sis/gui/map/MapCanvasAWT.java b/application/sis-javafx/src/main/java/org/apache/sis/gui/map/MapCanvasAWT.java
index 926d4be804..267efa7ce9 100644
--- a/application/sis-javafx/src/main/java/org/apache/sis/gui/map/MapCanvasAWT.java
+++ b/application/sis-javafx/src/main/java/org/apache/sis/gui/map/MapCanvasAWT.java
@@ -33,6 +33,7 @@ import javafx.application.Platform;
 import javafx.geometry.Bounds;
 import javafx.geometry.Insets;
 import javafx.geometry.Rectangle2D;
+import javafx.scene.Scene;
 import javafx.scene.image.ImageView;
 import javafx.scene.image.PixelBuffer;
 import javafx.scene.image.PixelFormat;
@@ -560,13 +561,34 @@ public abstract class MapCanvasAWT extends MapCanvas {
             return null;                                    // Indicate that the entire buffer was dirty.
         }
 
+        /**
+         * Invoked in JavaFX thread on success. The actual transfer from Java2D image to JavaFX image
+         * will happen just before the next pulse for making sure that the affine transform and the
+         * image are updated together before rendering. Doing that way avoid flickering effects.
+         */
+        @Override
+        protected void succeeded() {
+            final Scene scene = fixedPane.getScene();
+            if (scene != null) {
+                final Runnable pulseAction = new Runnable() {
+                    @Override public void run() {
+                        scene.removePreLayoutPulseListener(this);
+                        transferImage();
+                    }
+                };
+                scene.addPreLayoutPulseListener(pulseAction);
+                Platform.requestNextPulse();
+            } else {
+                transferImage();
+            }
+        }
+
         /**
          * Invoked in JavaFX thread on success. The JavaFX image is set to the result, then the double buffer
          * created by this task is saved in {@link MapCanvas} fields for reuse next time that an image of the
          * same size will be rendered again.
          */
-        @Override
-        protected void succeeded() {
+        private void transferImage() {
             final VolatileImage drawTo = getValue();
             doubleBuffer = drawTo;
             try {