Add ability to scale anti-alias fringe. This enable users to keep geo…

…metry sharp while scaling vertex buffer content.

imgui.h

@@ -1984,6 +1984,7 @@ struct ImDrawList
     ImVector<ImTextureID>   _TextureIdStack;    // [Internal]
     ImVector<ImVec2>        _Path;              // [Internal] current path building
     ImDrawListSplitter      _Splitter;          // [Internal] for channels api
+    float                   _FringeScale;       // [Internal] anti-alias fringe is scaled by this value, this helps to keep things sharp while zooming at vertex buffer content
 
     // If you want to create ImDrawList instances, pass them ImGui::GetDrawListSharedData() or create and use your own ImDrawListSharedData (so you can use ImDrawList without ImGui)
     ImDrawList(const ImDrawListSharedData* shared_data) { _Data = shared_data; _OwnerName = NULL; Clear(); }

imgui_draw.cpp

@@ -390,6 +390,7 @@ void ImDrawList::Clear()
     _TextureIdStack.resize(0);
     _Path.resize(0);
     _Splitter.Clear();
+    _FringeScale = 1.0f;
 }
 
 void ImDrawList::ClearFreeMemory()
@@ -632,11 +633,11 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
     if (!closed)
         count = points_count-1;
 
-    const bool thick_line = (thickness > 1.0f);
+    const bool thick_line = (thickness > _FringeScale);
     if (Flags & ImDrawListFlags_AntiAliasedLines)
     {
         // Anti-aliased stroke
-        const float AA_SIZE = 1.0f;
+        const float AA_SIZE = 1.0f * _FringeScale;
         const ImU32 col_trans = col & ~IM_COL32_A_MASK;
 
         const int idx_count = thick_line ? count*18 : count*12;
@@ -820,7 +821,7 @@ void ImDrawList::AddConvexPolyFilled(const ImVec2* points, const int points_coun
     if (Flags & ImDrawListFlags_AntiAliasedFill)
     {
         // Anti-aliased Fill
-        const float AA_SIZE = 1.0f;
+        const float AA_SIZE = 1.0f * _FringeScale;
         const ImU32 col_trans = col & ~IM_COL32_A_MASK;
         const int idx_count = (points_count-2)*3 + points_count*6;
         const int vtx_count = (points_count*2);