ImDrawList: added InitialFringeScale in ImDrawListSharedData. Default to 1.0f.

This is to allow some DPI mods with less changes. Only the initial value in SetupDrawListSharedData() will need change.

imgui_draw.cpp

@@ -374,6 +374,7 @@ void ImGui::StyleColorsLight(ImGuiStyle* dst)
 ImDrawListSharedData::ImDrawListSharedData()
 {
     memset(this, 0, sizeof(*this));
+    InitialFringeScale = 1.0f;
     for (int i = 0; i < IM_ARRAYSIZE(ArcFastVtx); i++)
     {
         const float a = ((float)i * 2 * IM_PI) / (float)IM_ARRAYSIZE(ArcFastVtx);
@@ -433,7 +434,7 @@ void ImDrawList::_ResetForNewFrame()
     _Path.resize(0);
     _Splitter.Clear();
     CmdBuffer.push_back(ImDrawCmd());
-    _FringeScale = 1.0f;
+    _FringeScale = _Data->InitialFringeScale;
 }
 
 void ImDrawList::_ClearFreeMemory()