Drag and Drop, Style: added basic styling options to DragDrop target rect. (#9056)

imgui.cpp

@@ -1450,6 +1450,9 @@ ImGuiStyle::ImGuiStyle()
     AntiAliasedFill             = true;             // Enable anti-aliased filled shapes (rounded rectangles, circles, etc.).
     CurveTessellationTol        = 1.25f;            // Tessellation tolerance when using PathBezierCurveTo() without a specific number of segments. Decrease for highly tessellated curves (higher quality, more polygons), increase to reduce quality.
     CircleTessellationMaxError  = 0.30f;            // Maximum error (in pixels) allowed when using AddCircle()/AddCircleFilled() or drawing rounded corner rectangles with no explicit segment count specified. Decrease for higher quality but more geometry.
+    DragDropTargetRectRounding  = 0.0f;             // Corner radius of the drag-drop hover frame
+    DragDropTargetRectLineThickness = 2.0f;         // Thickness of the drop-drop hover frame lines
+    DragDropTargetRectExpansionSize = 3.5f;         // The size in which the drag-drop hover rect will expand over the target
 
     // Behaviors
     HoverStationaryDelay        = 0.15f;            // Delay for IsItemHovered(ImGuiHoveredFlags_Stationary). Time required to consider mouse stationary.
@@ -3711,6 +3714,7 @@ const char* ImGui::GetStyleColorName(ImGuiCol idx)
     case ImGuiCol_TextSelectedBg: return "TextSelectedBg";
     case ImGuiCol_TreeLines: return "TreeLines";
     case ImGuiCol_DragDropTarget: return "DragDropTarget";
+    case ImGuiCol_DragDropTargetBg: return "DragDropTargetBg";
     case ImGuiCol_UnsavedMarker: return "UnsavedMarker";
     case ImGuiCol_NavCursor: return "NavCursor";
     case ImGuiCol_NavWindowingHighlight: return "NavWindowingHighlight";
@@ -14893,7 +14897,7 @@ void ImGui::RenderDragDropTargetRectForItem(const ImRect& bb)
     ImGuiWindow* window = g.CurrentWindow;
     ImRect bb_display = bb;
     bb_display.ClipWith(g.DragDropTargetClipRect); // Clip THEN expand so we have a way to visualize that target is not entirely visible.
-    bb_display.Expand(3.5f);
+    bb_display.Expand(g.Style.DragDropTargetRectExpansionSize);
     bool push_clip_rect = !window->ClipRect.Contains(bb_display);
     if (push_clip_rect)
         window->DrawList->PushClipRectFullScreen();
@@ -14904,7 +14908,13 @@ void ImGui::RenderDragDropTargetRectForItem(const ImRect& bb)
 
 void ImGui::RenderDragDropTargetRectEx(ImDrawList* draw_list, const ImRect& bb)
 {
-    draw_list->AddRect(bb.Min, bb.Max, GetColorU32(ImGuiCol_DragDropTarget), 0.0f, 0, 2.0f); // FIXME-DPI
+    ImGuiContext& g = *GImGui;
+
+    const ImVec4& color_bg = GetStyleColorVec4(ImGuiCol_DragDropTargetBg);
+    if (color_bg.w > 0.0f)
+        draw_list->AddRectFilled(bb.Min, bb.Max, GetColorU32(color_bg), g.Style.DragDropTargetRectRounding, 0);
+
+    draw_list->AddRect(bb.Min, bb.Max, GetColorU32(ImGuiCol_DragDropTarget), g.Style.DragDropTargetRectRounding, 0, g.Style.DragDropTargetRectLineThickness); // FIXME-DPI
 }
 
 const ImGuiPayload* ImGui::GetDragDropPayload()

imgui.h

@@ -1776,7 +1776,8 @@ enum ImGuiCol_
     ImGuiCol_TextLink,              // Hyperlink color
     ImGuiCol_TextSelectedBg,        // Selected text inside an InputText
     ImGuiCol_TreeLines,             // Tree node hierarchy outlines when using ImGuiTreeNodeFlags_DrawLines
-    ImGuiCol_DragDropTarget,        // Rectangle highlighting a drop target
+    ImGuiCol_DragDropTarget,        // Rectangle border highlighting a drop target
+    ImGuiCol_DragDropTargetBg,      // Rectangle background highlighting a drop target
     ImGuiCol_UnsavedMarker,         // Unsaved Document marker (in window title and tabs)
     ImGuiCol_NavCursor,             // Color of keyboard/gamepad navigation cursor/rectangle, when visible
     ImGuiCol_NavWindowingHighlight, // Highlight window when using CTRL+TAB
@@ -2322,6 +2323,9 @@ struct ImGuiStyle
     bool        AntiAliasedFill;            // Enable anti-aliased edges around filled shapes (rounded rectangles, circles, etc.). Disable if you are really tight on CPU/GPU. Latched at the beginning of the frame (copied to ImDrawList).
     float       CurveTessellationTol;       // Tessellation tolerance when using PathBezierCurveTo() without a specific number of segments. Decrease for highly tessellated curves (higher quality, more polygons), increase to reduce quality.
     float       CircleTessellationMaxError; // Maximum error (in pixels) allowed when using AddCircle()/AddCircleFilled() or drawing rounded corner rectangles with no explicit segment count specified. Decrease for higher quality but more geometry.
+    float       DragDropTargetRectRounding; // Corner radius of the drag-drop target rect
+    float       DragDropTargetRectLineThickness; // Thickness of the drop-drop target rect lines
+    float       DragDropTargetRectExpansionSize; // The size in which the drag-drop target rect will expand over the target
 
     // Colors
     ImVec4      Colors[ImGuiCol_COUNT];

imgui_draw.cpp

@@ -240,6 +240,7 @@ void ImGui::StyleColorsDark(ImGuiStyle* dst)
     colors[ImGuiCol_TextSelectedBg]         = ImVec4(0.26f, 0.59f, 0.98f, 0.35f);
     colors[ImGuiCol_TreeLines]              = colors[ImGuiCol_Border];
     colors[ImGuiCol_DragDropTarget]         = ImVec4(1.00f, 1.00f, 0.00f, 0.90f);
+    colors[ImGuiCol_DragDropTargetBg]       = ImVec4(0.00f, 0.00f, 0.00f, 0.00f);
     colors[ImGuiCol_UnsavedMarker]          = ImVec4(1.00f, 1.00f, 1.00f, 1.00f);
     colors[ImGuiCol_NavCursor]              = ImVec4(0.26f, 0.59f, 0.98f, 1.00f);
     colors[ImGuiCol_NavWindowingHighlight]  = ImVec4(1.00f, 1.00f, 1.00f, 0.70f);
@@ -306,6 +307,7 @@ void ImGui::StyleColorsClassic(ImGuiStyle* dst)
     colors[ImGuiCol_TextSelectedBg]         = ImVec4(0.00f, 0.00f, 1.00f, 0.35f);
     colors[ImGuiCol_TreeLines]              = colors[ImGuiCol_Border];
     colors[ImGuiCol_DragDropTarget]         = ImVec4(1.00f, 1.00f, 0.00f, 0.90f);
+    colors[ImGuiCol_DragDropTargetBg]       = ImVec4(0.00f, 0.00f, 0.00f, 0.00f);
     colors[ImGuiCol_UnsavedMarker]          = ImVec4(0.90f, 0.90f, 0.90f, 1.00f);
     colors[ImGuiCol_NavCursor]              = colors[ImGuiCol_HeaderHovered];
     colors[ImGuiCol_NavWindowingHighlight]  = ImVec4(1.00f, 1.00f, 1.00f, 0.70f);
@@ -373,6 +375,7 @@ void ImGui::StyleColorsLight(ImGuiStyle* dst)
     colors[ImGuiCol_TextSelectedBg]         = ImVec4(0.26f, 0.59f, 0.98f, 0.35f);
     colors[ImGuiCol_TreeLines]              = colors[ImGuiCol_Border];
     colors[ImGuiCol_DragDropTarget]         = ImVec4(0.26f, 0.59f, 0.98f, 0.95f);
+    colors[ImGuiCol_DragDropTargetBg]       = ImVec4(0.00f, 0.00f, 0.00f, 0.00f);
     colors[ImGuiCol_UnsavedMarker]          = ImVec4(0.00f, 0.00f, 0.00f, 1.00f);
     colors[ImGuiCol_NavCursor]              = colors[ImGuiCol_HeaderHovered];
     colors[ImGuiCol_NavWindowingHighlight]  = ImVec4(0.70f, 0.70f, 0.70f, 0.70f);