Invalidate Preview Window when pasting Frame (fix #2215)

[Joefish]

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[Joefish]

While the original Issue #2215 that the frame editor was not updated when pasting a cel, was resolved, the preview window still did not update correctly. I know throwing another widget invalidate in there is not the best solution. I am still new to the code base so it took me a bit to understand how the messaging and observer system work in this case.
PreviewEditorWindow inherits from EditorObserver, and although it has onBefore/AfterFrameChanged, it didn't fire when the Cel was pasted and rendered in the editor. The Document observer interface has a onCelCopied function that could be used by adding a DocObserver to the PreviewEditor Class would be needed or extending the Editor Class to forward the notify.
A working example would be like this,

diff --git a/src/app/ui/preview_editor.cpp b/src/app/ui/preview_editor.cpp
index 9c89a6fa5..4c63d96cd 100644
--- a/src/app/ui/preview_editor.cpp
+++ b/src/app/ui/preview_editor.cpp
@@ -379,6 +379,7 @@ void PreviewEditorWindow::updateUsingEditor(Editor* editor)
     miniEditor->setState(EditorStatePtr(new NavigateState));
     miniEditor->setAnimationSpeedMultiplier(m_aniSpeed);
     miniEditor->add_observer(this);
+    document->add_observer(this);
     layout();
·
     if (!autoScroll)
@@ -513,4 +514,9 @@ void PreviewEditorWindow::adjustPlayingTag()
                    Preferences::instance().preview.playAll());
 }
·
+void PreviewEditorWindow::onCelCopied(DocEvent &ev)
+{
+  invalidate();
+}
+
 } // namespace app
diff --git a/src/app/ui/preview_editor.h b/src/app/ui/preview_editor.h
index ec7d20c7e..ea0c6fdf3 100644
--- a/src/app/ui/preview_editor.h
+++ b/src/app/ui/preview_editor.h
@@ -21,6 +21,7 @@ namespace app {
·
   class PreviewEditorWindow : public ui::Window
                             , public EditorObserver
+                            , public DocObserver
                             , public DocViewPreviewDelegate {
   public:
     PreviewEditorWindow();
@@ -51,6 +52,8 @@ namespace app {
     void onClose(ui::CloseEvent& ev) override;
     void onWindowResize() override;
·
+    void onCelCopied(DocEvent& ev) override;
+
   private:
     void uncheckCenterButton();
     bool hasDocument() const;

But as I said I wanted to keep the changes to a minimum and imo another observer class just for this would be overkill.

[dacap]

Thanks for your PR @Joefish 👍 I've just tested and while it fixes the problem with the preview editor, I saw that it doesn't fix the problem if we have multiple editors, e.g. (in second 0:05 the cel is pasted):

Screencast.2022-11-17.11.17.18.mp4

As you saw, an onCelCopied solution might be better, but I've found other bigger problems when frames are copied (whole frames). I'll review the behavior of cels, frames, and layers, and fix them.

[dacap]

I've used Doc::notifyGeneralUpdate to update all visible Editor/DocView: d8c1b19

Also there were a missing redraw when copying/pasting frames (not cels) in the same doc (the DocRange::kFrames case). This was fixed too in the commit. Thanks for your help @Joefish to detect and fix this issue 👍