Fix scroll wheel interaction across graph editor windows (#1578)

Fixed scroll wheel causing both the renderview to zoom as well as the property editor to scroll.
This is done by moving the renderview cursor bounds check up on the call stack and adding flags to disable scrolling for the property editor if the cursor is within the renderview.

Author: HudsonHN

source/MaterialXGraphEditor/Graph.cpp

@@ -3241,13 +3241,27 @@ 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]);
 
@@ -3267,7 +3281,10 @@ void Graph::graphButtons()
     ImGui::EndChild();
     ImGui::SameLine(0.0f, 12.0f);
 
-    handleRenderViewInputs(windowPos, screenSize[0], screenSize[1]);
+    if (cursorInRenderView)
+    {
+        handleRenderViewInputs();
+    }
 }
 
 void Graph::propertyEditor()
@@ -3830,56 +3847,54 @@ 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)

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);