From a0b68cbc9f81555c5492d5cbfe77d3cb1eca8521 Mon Sep 17 00:00:00 2001
From: thedmd <michcic@gmail.com>
Date: Wed, 27 Dec 2023 13:15:30 +0100
Subject: [PATCH] Editor: Add smooth zoom (#266)

---
 docs/CHANGELOG.txt           |  2 ++
 imgui_node_editor.cpp        | 29 +++++++++++++++++++++++++++--
 imgui_node_editor.h          | 10 +++++++++-
 imgui_node_editor_internal.h |  2 ++
 4 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index d1f9b320..f41699fd 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -6,6 +6,8 @@ v0.10.0 (WIP):
 
     NEW: Canvas: Add example of zooming at fixed point (#270)
 
+    NEW: Editor: Add smooth zoom (#266)
+
     CHANGE: Canvas: Use ImDrawCallback_ImCanvas macro as draw callback sentinel (#256), thanks @nspitko
 
     BUGFIX: Examples: Call ed::EndCreate() and ed::EndDelete() only when ed::BeginCreate() and ed::BeginDelete() returned true
diff --git a/imgui_node_editor.cpp b/imgui_node_editor.cpp
index 2adf0279..a46beabd 100644
--- a/imgui_node_editor.cpp
+++ b/imgui_node_editor.cpp
@@ -3449,8 +3449,7 @@ bool ed::NavigateAction::HandleZoom(const Control& control)
     m_Animation.Finish();
 
     auto mousePos = io.MousePos;
-    auto steps    = (int)io.MouseWheel;
-    auto newZoom  = MatchZoom(steps, m_ZoomLevels[steps < 0 ? 0 : m_ZoomLevelCount - 1]);
+    auto newZoom  = GetNextZoom(io.MouseWheel);
 
     auto oldView   = GetView();
     m_Zoom = newZoom;
@@ -3626,6 +3625,32 @@ ImRect ed::NavigateAction::GetViewRect() const
     return m_Canvas.CalcViewRect(GetView());
 }
 
+float ed::NavigateAction::GetNextZoom(float steps)
+{
+    if (this->Editor->GetConfig().EnableSmoothZoom)
+    {
+        return MatchSmoothZoom(steps);
+    }
+    else
+    {
+        auto fixedSteps = (int)steps;
+        return MatchZoom(fixedSteps, m_ZoomLevels[fixedSteps < 0 ? 0 : m_ZoomLevelCount - 1]);
+    }
+}
+
+float ed::NavigateAction::MatchSmoothZoom(float steps)
+{
+    const auto power = Editor->GetConfig().SmoothZoomPower;
+
+    const auto newZoom = m_Zoom * powf(power, steps);
+    if (newZoom < m_ZoomLevels[0])
+        return m_ZoomLevels[0];
+    else if (newZoom > m_ZoomLevels[m_ZoomLevelCount - 1])
+        return m_ZoomLevels[m_ZoomLevelCount - 1];
+    else
+        return newZoom;
+}
+
 float ed::NavigateAction::MatchZoom(int steps, float fallbackZoom)
 {
     auto currentZoomIndex = MatchZoomIndex(steps);
diff --git a/imgui_node_editor.h b/imgui_node_editor.h
index 5f7289b2..38532bdc 100644
--- a/imgui_node_editor.h
+++ b/imgui_node_editor.h
@@ -105,6 +105,8 @@ struct Config
     int                     SelectButtonIndex;      // Mouse button index select action will react to (0-left, 1-right, 2-middle)
     int                     NavigateButtonIndex;    // Mouse button index navigate action will react to (0-left, 1-right, 2-middle)
     int                     ContextMenuButtonIndex; // Mouse button index context menu action will react to (0-left, 1-right, 2-middle)
+    bool                    EnableSmoothZoom;
+    float                   SmoothZoomPower;
 
     Config()
         : SettingsFile("NodeEditor.json")
@@ -121,6 +123,12 @@ struct Config
         , SelectButtonIndex(0)
         , NavigateButtonIndex(1)
         , ContextMenuButtonIndex(1)
+        , EnableSmoothZoom(true)
+# ifdef __APPLE__
+        , SmoothZoomPower(1.1f)
+# else
+        , SmoothZoomPower(1.3f)
+# endif
     {
     }
 };
@@ -519,4 +527,4 @@ struct PinId final: Details::SafePointerType<PinId>
 
 
 //------------------------------------------------------------------------------
-# endif // __IMGUI_NODE_EDITOR_H__
\ No newline at end of file
+# endif // __IMGUI_NODE_EDITOR_H__
diff --git a/imgui_node_editor_internal.h b/imgui_node_editor_internal.h
index 33c74225..0d018cf5 100644
--- a/imgui_node_editor_internal.h
+++ b/imgui_node_editor_internal.h
@@ -886,6 +886,8 @@ struct NavigateAction final: EditorAction
 
     void NavigateTo(const ImRect& target, float duration = -1.0f, NavigationReason reason = NavigationReason::Unknown);
 
+    float GetNextZoom(float steps);
+    float MatchSmoothZoom(float steps);
     float MatchZoom(int steps, float fallbackZoom);
     int MatchZoomIndex(int direction);