From c57f071f0c8c9f52762ac3bd0e9d87369ca95f8b Mon Sep 17 00:00:00 2001
From: David Given <dg@cowlark.com>
Date: Sat, 29 Nov 2025 13:01:38 +0100
Subject: [PATCH] impr: Add hooks to let Views to get notified when they are
 opened or closed (#2493)

This is a trivial change which adds virtual methods to View, `onOpen()`
and `onClose()`, which are called when the view is opened or closed.

This information is already tracked inside the View, but not exposed via
the API. There is `didWindowJustOpen()` and `didWindowJustClose()`, but
these fetch and then reset the flag, so they can't be used more than
once in a frame (and are sometimes called by the frame, meaning the flag
has already been consumed by the time the View's draw callback gets
called).

The use case here is that I have a View which needs to do some work
every time it's shown.
---
 lib/libimhex/include/hex/ui/view.hpp | 11 +++++++++++
 lib/libimhex/source/ui/view.cpp      |  6 +++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/lib/libimhex/include/hex/ui/view.hpp b/lib/libimhex/include/hex/ui/view.hpp
index c125a271b..0637ecaf9 100644
--- a/lib/libimhex/include/hex/ui/view.hpp
+++ b/lib/libimhex/include/hex/ui/view.hpp
@@ -110,6 +110,17 @@ namespace hex {
         void trackViewState();
         void setFocused(bool focused);
 
+    protected:
+        /**
+         * @brief Called when this view is opened (i.e. made visible).
+         */
+        virtual void onOpen() {}
+
+        /**
+         * @brief Called when this view is closed (i.e. made invisible).
+         */
+        virtual void onClose() {}
+
     public:
         class Window;
         class Special;
diff --git a/lib/libimhex/source/ui/view.cpp b/lib/libimhex/source/ui/view.cpp
index fee0ff517..8bdc3cb97 100644
--- a/lib/libimhex/source/ui/view.cpp
+++ b/lib/libimhex/source/ui/view.cpp
@@ -75,9 +75,13 @@ namespace hex {
 
     void View::trackViewState() {
         if (m_windowOpen && !m_prevWindowOpen)
+        {
             this->setWindowJustOpened(true);
-        else if (!m_windowOpen && m_prevWindowOpen)
+            this->onOpen();
+        } else if (!m_windowOpen && m_prevWindowOpen) {
             this->setWindowJustClosed(true);
+            this->onClose();
+        }
         m_prevWindowOpen = m_windowOpen;
     }