From 7a05857310fd456c0508076576a7f7d204bd31b5 Mon Sep 17 00:00:00 2001
From: HudsonHN <hudsonhn@usc.edu>
Date: Thu, 19 Oct 2023 03:25:44 -0700
Subject: [PATCH] Fix: Scroll wheel zooms and scrolls property editor

Fixed the issue where using the scroll wheel will both zoom in the renderview as well as the panel bar.
This is done by doing a cursor bounds check and disabling scrolling for the panel if the cursor is inside the renderview.
---
 source/MaterialXGraphEditor/Graph.cpp | 113 +++++++++++++++-----------
 source/MaterialXGraphEditor/Graph.h   |   2 +-
 2 files changed, 65 insertions(+), 50 deletions(-)

diff --git a/source/MaterialXGraphEditor/Graph.cpp b/source/MaterialXGraphEditor/Graph.cpp
index 439f720e2e..e2c8fe9ae3 100644
--- a/source/MaterialXGraphEditor/Graph.cpp
+++ b/source/MaterialXGraphEditor/Graph.cpp
@@ -3245,13 +3245,27 @@ void Graph::graphButtons()
 
     // Create two windows using splitter
     float paneWidth = (leftPaneWidth - 2.0f);
-    ImGui::BeginChild("Selection", ImVec2(paneWidth, 0));
+    
+    float aspectRatio = _renderer->getPixelRatio();
+    ImVec2 screenSize = ImVec2(paneWidth, paneWidth / aspectRatio);
+
+    ImVec2 mousePos = ImGui::GetMousePos();
+    ImVec2 tempWindowPos = ImGui::GetCursorPos();
+    bool cursorInRenderView = mousePos.x > tempWindowPos.x && mousePos.x < (tempWindowPos.x + screenSize.x) &&
+                              mousePos.y > tempWindowPos.y && mousePos.y < (tempWindowPos.y + screenSize.y);
+    
+    ImGuiWindowFlags windowFlags = 0;
+
+    if (cursorInRenderView)
+    {
+        windowFlags |= ImGuiWindowFlags_NoScrollWithMouse;
+    }
+    
+    ImGui::BeginChild("Selection", ImVec2(paneWidth, 0), false, windowFlags);
     ImVec2 windowPos = ImGui::GetWindowPos();
 
     // RenderView window
     ImVec2 wsize = ImVec2((float) _renderer->getViewWidth(), (float) _renderer->getViewHeight());
-    float aspectRatio = _renderer->getPixelRatio();
-    ImVec2 screenSize = ImVec2(paneWidth, paneWidth / aspectRatio);
     _renderer->setViewWidth((int) screenSize[0]);
     _renderer->setViewHeight((int) screenSize[1]);
 
@@ -3271,7 +3285,10 @@ void Graph::graphButtons()
     ImGui::EndChild();
     ImGui::SameLine(0.0f, 12.0f);
 
-    handleRenderViewInputs(windowPos, screenSize[0], screenSize[1]);
+    if (cursorInRenderView)
+    {
+        handleRenderViewInputs();
+    }
 }
 
 void Graph::propertyEditor()
@@ -3839,56 +3856,54 @@ void Graph::shaderPopup()
     }
 }
 
-void Graph::handleRenderViewInputs(ImVec2 minValue, float width, float height)
+void Graph::handleRenderViewInputs()
 {
     ImVec2 mousePos = ImGui::GetMousePos();
-    if (mousePos.x > minValue.x && mousePos.x < (minValue.x + width) && mousePos.y > minValue.y && mousePos.y < (minValue.y + height))
+    mx::Vector2 mxMousePos = mx::Vector2(mousePos.x, mousePos.y);
+    float scrollAmt = ImGui::GetIO().MouseWheel;
+    int button = -1;
+    bool down = false;
+    if (ImGui::IsMouseDragging(0) || ImGui::IsMouseDragging(1))
     {
-        mx::Vector2 mxMousePos = mx::Vector2(mousePos.x, mousePos.y);
-        float scrollAmt = ImGui::GetIO().MouseWheel;
-        int button = -1;
-        bool down = false;
-        if (ImGui::IsMouseDragging(0) || ImGui::IsMouseDragging(1))
-        {
-            _renderer->setMouseMotionEvent(mxMousePos);
-        }
-        if (ImGui::IsMouseClicked(0))
-        {
-            button = 0;
-            down = true;
-            _renderer->setMouseButtonEvent(button, down, mxMousePos);
-        }
-        else if (ImGui::IsMouseClicked(1))
-        {
-            button = 1;
-            down = true;
-            _renderer->setMouseButtonEvent(button, down, mxMousePos);
-        }
-        else if (ImGui::IsMouseReleased(0))
-        {
-            button = 0;
-            _renderer->setMouseButtonEvent(button, down, mxMousePos);
-        }
-        else if (ImGui::IsMouseReleased(1))
-        {
-            button = 1;
-            _renderer->setMouseButtonEvent(button, down, mxMousePos);
-        }
-        else if (ImGui::IsKeyPressed(ImGuiKey_KeypadAdd))
-        {
-            _renderer->setKeyEvent(ImGuiKey_KeypadAdd);
-        }
-        else if (ImGui::IsKeyPressed(ImGuiKey_KeypadSubtract))
-        {
-            _renderer->setKeyEvent(ImGuiKey_KeypadSubtract);
-        }
+        _renderer->setMouseMotionEvent(mxMousePos);
+    }
+    if (ImGui::IsMouseClicked(0))
+    {
+        button = 0;
+        down = true;
+        _renderer->setMouseButtonEvent(button, down, mxMousePos);
+    }
+    else if (ImGui::IsMouseClicked(1))
+    {
+        button = 1;
+        down = true;
+        _renderer->setMouseButtonEvent(button, down, mxMousePos);
+    }
+    else if (ImGui::IsMouseReleased(0))
+    {
+        button = 0;
+        _renderer->setMouseButtonEvent(button, down, mxMousePos);
+    }
+    else if (ImGui::IsMouseReleased(1))
+    {
+        button = 1;
+        _renderer->setMouseButtonEvent(button, down, mxMousePos);
+    }
+    else if (ImGui::IsKeyPressed(ImGuiKey_KeypadAdd))
+    {
+        _renderer->setKeyEvent(ImGuiKey_KeypadAdd);
+    }
+    else if (ImGui::IsKeyPressed(ImGuiKey_KeypadSubtract))
+    {
+        _renderer->setKeyEvent(ImGuiKey_KeypadSubtract);
+    }
 
-        // Scrolling not possible if open or save file dialog is open
-        if (scrollAmt != 0 && !_fileDialogSave.isOpened() && !_fileDialog.isOpened() && !_fileDialogGeom.isOpened())
-        {
-            _renderer->setScrollEvent(scrollAmt);
-        }
+    // Scrolling not possible if open or save file dialog is open
+    if (scrollAmt != 0 && !_fileDialogSave.isOpened() && !_fileDialog.isOpened() && !_fileDialogGeom.isOpened())
+    {
+        _renderer->setScrollEvent(scrollAmt);
     }
+    
 }
 
 void Graph::drawGraph(ImVec2 mousePos)
diff --git a/source/MaterialXGraphEditor/Graph.h b/source/MaterialXGraphEditor/Graph.h
index fcdf93723e..821ecf71fd 100644
--- a/source/MaterialXGraphEditor/Graph.h
+++ b/source/MaterialXGraphEditor/Graph.h
@@ -225,7 +225,7 @@ class Graph
     void selectMaterial(UiNodePtr node);
 
     // Allow for camera manipulation of render view window
-    void handleRenderViewInputs(ImVec2 minValue, float width, float height);
+    void handleRenderViewInputs();
 
     // Set the node to display in render view based on selected node or nodegraph
     void setRenderMaterial(UiNodePtr node);