Editor: Make selection rect start at click point

Author: thedmd

docs/CHANGELOG.txt

@@ -179,3 +179,4 @@ v0.9.1 (WIP):
 
     BUGFIX: Editor: Improve link dragging with fast movement (#156)
 
+    BUGFIX: Editor: Make selection rect start at click point

imgui_node_editor.cpp

@@ -3917,7 +3917,7 @@ ed::EditorAction::AcceptResult ed::SelectAction::Accept(const Control& control)
     if (Editor->CanAcceptUserInput() && control.BackgroundHot && ImGui::IsMouseDragging(Editor->GetConfig().SelectButtonIndex, 1))
     {
         m_IsActive = true;
-        m_StartPoint = ImGui::GetMousePos();
+        m_StartPoint = ImGui_GetMouseClickPos(Editor->GetConfig().SelectButtonIndex);
         m_EndPoint   = m_StartPoint;
 
         // Links and nodes cannot be selected together

imgui_node_editor_internal.h

@@ -56,6 +56,7 @@ void Log(const char* fmt, ...);
 //inline ImRect ToRect(const ax::rectf& rect);
 //inline ImRect ToRect(const ax::rect& rect);
 inline ImRect ImGui_GetItemRect();
+inline ImVec2 ImGui_GetMouseClickPos(ImGuiMouseButton buttonIndex);
 
 
 //------------------------------------------------------------------------------

imgui_node_editor_internal.inl

@@ -46,6 +46,14 @@ inline ImRect ImGui_GetItemRect()
     return ImRect(ImGui::GetItemRectMin(), ImGui::GetItemRectMax());
 }
 
+inline ImVec2 ImGui_GetMouseClickPos(ImGuiMouseButton buttonIndex)
+{
+    if (ImGui::IsMouseDown(buttonIndex))
+        return ImGui::GetIO().MouseClickedPos[buttonIndex];
+    else
+        return ImGui::GetMousePos();
+}
+
 
 //------------------------------------------------------------------------------
 } // namespace Detail