MultiSelect: Box-Select: added scroll support.

imgui.h

@@ -2734,6 +2734,7 @@ enum ImGuiMultiSelectFlags_
     ImGuiMultiSelectFlags_SingleSelect          = 1 << 0,   // Disable selecting more than one item. This is available to allow single-selection code to use same code/logic is desired, but may not be very useful.
     ImGuiMultiSelectFlags_NoSelectAll           = 1 << 1,   // Disable CTRL+A shortcut to set RequestSelectAll
     ImGuiMultiSelectFlags_BoxSelect             = 1 << 2,   // Enable box-selection. Box-selection works better with little bit of spacing between items hit-box in order to be able to aim at empty space.
+    ImGuiMultiSelectFlags_NoBoxSelectScroll     = 1 << 3,   // Disable scrolling when box-selecting near edges of scope.
     ImGuiMultiSelectFlags_ClearOnEscape         = 1 << 4,   // Clear selection when pressing Escape while scope is focused.
     ImGuiMultiSelectFlags_ClearOnClickVoid      = 1 << 5,   // Clear selection when clicking on empty location within scope.
     ImGuiMultiSelectFlags_ScopeWindow           = 1 << 6,   // Scope for _ClearOnClickVoid and _BoxSelect is whole window (Default). Use if (use if BeginMultiSelect() covers a whole window.

imgui_demo.cpp

@@ -3362,6 +3362,7 @@ static void ShowDemoWindowMultiSelect()
             ImGui::CheckboxFlags("ImGuiMultiSelectFlags_SingleSelect", &flags, ImGuiMultiSelectFlags_SingleSelect);
             ImGui::CheckboxFlags("ImGuiMultiSelectFlags_NoSelectAll", &flags, ImGuiMultiSelectFlags_NoSelectAll);
             ImGui::CheckboxFlags("ImGuiMultiSelectFlags_BoxSelect", &flags, ImGuiMultiSelectFlags_BoxSelect);
+            ImGui::CheckboxFlags("ImGuiMultiSelectFlags_NoBoxSelectScroll", &flags, ImGuiMultiSelectFlags_NoBoxSelectScroll);
             ImGui::CheckboxFlags("ImGuiMultiSelectFlags_ClearOnEscape", &flags, ImGuiMultiSelectFlags_ClearOnEscape);
             ImGui::CheckboxFlags("ImGuiMultiSelectFlags_ClearOnClickVoid", &flags, ImGuiMultiSelectFlags_ClearOnClickVoid);
             if (ImGui::CheckboxFlags("ImGuiMultiSelectFlags_ScopeWindow", &flags, ImGuiMultiSelectFlags_ScopeWindow) && (flags & ImGuiMultiSelectFlags_ScopeWindow))
@@ -3372,7 +3373,7 @@ static void ShowDemoWindowMultiSelect()
                 flags &= ~ImGuiMultiSelectFlags_SelectOnClickRelease;
             if (ImGui::CheckboxFlags("ImGuiMultiSelectFlags_SelectOnClickRelease", &flags, ImGuiMultiSelectFlags_SelectOnClickRelease) && (flags & ImGuiMultiSelectFlags_SelectOnClickRelease))
                 flags &= ~ImGuiMultiSelectFlags_SelectOnClick;
-            ImGui::SameLine();  HelpMarker("Allow dragging an unselected item without altering selection.");
+            ImGui::SameLine(); HelpMarker("Allow dragging an unselected item without altering selection.");
 
             // Initialize default list with 1000 items.
             static ImVector<int> items;

imgui_internal.h

@@ -490,6 +490,7 @@ static inline int    ImModPositive(int a, int b)
 static inline float  ImDot(const ImVec2& a, const ImVec2& b)                    { return a.x * b.x + a.y * b.y; }
 static inline ImVec2 ImRotate(const ImVec2& v, float cos_a, float sin_a)        { return ImVec2(v.x * cos_a - v.y * sin_a, v.x * sin_a + v.y * cos_a); }
 static inline float  ImLinearSweep(float current, float target, float speed)    { if (current < target) return ImMin(current + speed, target); if (current > target) return ImMax(current - speed, target); return current; }
+static inline float  ImLinearRemapClamp(float s0, float s1, float d0, float d1, float x) { return ImSaturate((x - s0) / (s1 - s0)) * (d1 - d0) + d0; }
 static inline ImVec2 ImMul(const ImVec2& lhs, const ImVec2& rhs)                { return ImVec2(lhs.x * rhs.x, lhs.y * rhs.y); }
 static inline bool   ImIsFloatAboveGuaranteedIntegerPrecision(float f)          { return f <= -16777216 || f >= 16777216; }
 static inline float  ImExponentialMovingAverage(float avg, float sample, int n) { avg -= avg / n; avg += sample / n; return avg; }

imgui_widgets.cpp

@@ -7105,6 +7105,7 @@ void ImGui::DebugNodeTypingSelectState(ImGuiTypingSelectState* data)
 //-------------------------------------------------------------------------
 // - DebugLogMultiSelectRequests() [Internal]
 // - BoxSelectStart() [Internal]
+// - BoxSelectScrollWithMouseDrag() [Internal]
 // - BeginMultiSelect()
 // - EndMultiSelect()
 // - SetNextItemSelectionUserData()
@@ -7133,6 +7134,23 @@ static void BoxSelectStart(ImGuiMultiSelectState* storage, ImGuiSelectionUserDat
     storage->BoxSelectStartPosRel = storage->BoxSelectEndPosRel = ImGui::WindowPosAbsToRel(g.CurrentWindow, g.IO.MousePos);
 }
 
+static void BoxSelectScrollWithMouseDrag(ImGuiWindow* window, const ImRect& r)
+{
+    ImGuiContext& g = *GImGui;
+    for (int n = 0; n < 2; n++)
+    {
+        float dist = (g.IO.MousePos[n] > r.Max[n]) ? g.IO.MousePos[n] - r.Max[n] : (g.IO.MousePos[n] < r.Min[n]) ? g.IO.MousePos[n] - r.Min[n] : 0.0f;
+        if (dist == 0.0f || (dist < 0.0f && window->Scroll[n] < 0.0f) || (dist > 0.0f && window->Scroll[n] >= window->ScrollMax[n]))
+            continue;
+        float speed_multiplier = ImLinearRemapClamp(g.FontSize, g.FontSize * 5.0f, 1.0f, 4.0f, ImAbs(dist)); // x1 to x4 depending on distance
+        float scroll_step = IM_ROUND(g.FontSize * 35.0f * speed_multiplier * ImSign(dist) * g.IO.DeltaTime);
+        if (n == 0)
+            ImGui::SetScrollX(window, window->Scroll[n] + scroll_step);
+        else
+            ImGui::SetScrollY(window, window->Scroll[n] + scroll_step);
+    }
+}
+
 // Return ImGuiMultiSelectIO structure. Lifetime: valid until corresponding call to EndMultiSelect().
 ImGuiMultiSelectIO* ImGui::BeginMultiSelect(ImGuiMultiSelectFlags flags)
 {
@@ -7142,6 +7160,8 @@ ImGuiMultiSelectIO* ImGui::BeginMultiSelect(ImGuiMultiSelectFlags flags)
     IM_ASSERT(g.CurrentMultiSelect == NULL); // No recursion allowed yet (we could allow it if we deem it useful)
     IM_STATIC_ASSERT(offsetof(ImGuiMultiSelectTempData, IO) == 0); // Clear() relies on that.
     g.CurrentMultiSelect = ms;
+    if ((flags & (ImGuiMultiSelectFlags_ScopeWindow | ImGuiMultiSelectFlags_ScopeRect)) == 0)
+        flags |= ImGuiMultiSelectFlags_ScopeWindow;
 
     // FIXME: BeginFocusScope()
     const ImGuiID id = window->IDStack.back();
@@ -7257,6 +7277,7 @@ ImGuiMultiSelectIO* ImGui::EndMultiSelect()
     IM_ASSERT(ms->FocusScopeId == g.CurrentFocusScopeId);
     IM_ASSERT(g.CurrentMultiSelect != NULL && storage->Window == g.CurrentWindow);
 
+    const ImRect scope_rect = (ms->Flags & ImGuiMultiSelectFlags_ScopeRect) ? ImRect(ms->ScopeRectMin, ImMax(window->DC.CursorMaxPos, ms->ScopeRectMin)) : window->InnerClipRect;
     if (ms->IsFocused)
     {
         // We currently don't allow user code to modify RangeSrcItem by writing to BeginIO's version, but that would be an easy change here.
@@ -7272,25 +7293,30 @@ ImGuiMultiSelectIO* ImGui::EndMultiSelect()
             storage->NavIdSelected = -1;
         }
 
-        // Box-select: render selection rectangle
-        // FIXME-MULTISELECT: Scroll on box-select
         if ((ms->Flags & ImGuiMultiSelectFlags_BoxSelect) && storage->BoxSelectActive)
         {
+            // Box-select: render selection rectangle
             ms->Storage->BoxSelectEndPosRel = WindowPosAbsToRel(window, g.IO.MousePos);
-            window->DrawList->AddRectFilled(ms->BoxSelectRectCurr.Min, ms->BoxSelectRectCurr.Max, GetColorU32(ImGuiCol_SeparatorHovered, 0.30f)); // FIXME-MULTISELECT: Styling
-            window->DrawList->AddRect(ms->BoxSelectRectCurr.Min, ms->BoxSelectRectCurr.Max, GetColorU32(ImGuiCol_NavHighlight)); // FIXME-MULTISELECT: Styling
+            ImRect box_select_r = ms->BoxSelectRectCurr;
+            box_select_r.ClipWith(scope_rect);
+            window->DrawList->AddRectFilled(box_select_r.Min, box_select_r.Max, GetColorU32(ImGuiCol_SeparatorHovered, 0.30f)); // FIXME-MULTISELECT: Styling
+            window->DrawList->AddRect(box_select_r.Min, box_select_r.Max, GetColorU32(ImGuiCol_NavHighlight)); // FIXME-MULTISELECT: Styling
+
+            // Box-select: scroll
+            ImRect scroll_r = scope_rect;
+            scroll_r.Expand(g.Style.FramePadding);
+            if ((ms->Flags & ImGuiMultiSelectFlags_ScopeWindow) && (ms->Flags & ImGuiMultiSelectFlags_NoBoxSelectScroll) == 0 && !scroll_r.Contains(g.IO.MousePos))
+                BoxSelectScrollWithMouseDrag(window, scroll_r);
         }
     }
 
     if (ms->IsEndIO == false)
         ms->IO.Requests.resize(0);
 
-    const ImRect scope_rect(ms->ScopeRectMin, ImMax(window->DC.CursorMaxPos, ms->ScopeRectMin));
-    const bool scope_hovered = (ms->Flags & ImGuiMultiSelectFlags_ScopeRect) ? IsMouseHoveringRect(scope_rect.Min, scope_rect.Max) : IsWindowHovered();
-
     // Clear selection when clicking void?
     // We specifically test for IsMouseDragPastThreshold(0) == false to allow box-selection!
-    if (scope_hovered && g.HoveredId == 0)
+    const bool scope_hovered = (ms->Flags & ImGuiMultiSelectFlags_ScopeRect) ? scope_rect.Contains(g.IO.MousePos) : IsWindowHovered();
+    if (scope_hovered && g.HoveredId == 0 && g.ActiveId == 0)
     {
         if (ms->Flags & ImGuiMultiSelectFlags_BoxSelect)
             if (!storage->BoxSelectActive && !storage->BoxSelectStarting && g.IO.MouseClickedCount[0] == 1)