DrawList: apply current pixel density to DrawList's fringe scale. Added ImDrawList::_SetPixelDensity(). Reword FontRasterizerDensity as CurrentPixelDensity.

Amend 94a4322. # Conflicts: # imgui.cpp # imgui.h # imgui_draw.cpp # imgui_internal.h
2026-08-21 06:41:09 +00:00 · 2026-08-03 19:11:05 +02:00
parent fdc1152281
commit 5108603789
5 changed files with 30 additions and 18 deletions
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -51,7 +51,11 @@ Other Changes:
 - Fonts:
  - Reworked `AddFontDefault()` to use `io.DisplayFrameBufferScale` as part of the heuristic
    to select `AddFontDefaultVector()` by default, effectively using ProggyForever instead of
-    ProggyClean on most Mac setups by default.
+    ProggyClean on most Apple/Retina setups by default.
+- ImDrawList:
+  - Per-viewport FramebufferScale for Apple/Retina screen is applied to draw lists:
+    - AA Fringe is scaled accordingly.
+    - Circle and Curves tessellation error are scaled accordingly.


 -----------------------------------------------------------------------
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -4240,7 +4240,7 @@ ImGuiContext::ImGuiContext(ImFontAtlas* shared_font_atlas)
    Font = NULL;
    FontBaked = NULL;
    FontSize = FontSizeBase = FontBakedScale = CurrentDpiScale = 0.0f;
-    FontRasterizerDensity = 1.0f;
+    CurrentPixelDensity = 1.0f;
    IO.Fonts = shared_font_atlas ? shared_font_atlas : IM_NEW(ImFontAtlas)();
    if (shared_font_atlas == NULL)
        IO.Fonts->OwnerContext = this;
@@ -4711,7 +4711,7 @@ static void SetCurrentWindow(ImGuiWindow* window)
        if (g.IO.BackendFlags & ImGuiBackendFlags_RendererHasTextures)
        {
            ImGuiViewport* viewport = window->Viewport;
-            g.FontRasterizerDensity = (viewport->FramebufferScale.x != 0.0f) ? viewport->FramebufferScale.x : g.IO.DisplayFramebufferScale.x; // == SetFontRasterizerDensity()
+            g.CurrentPixelDensity = (viewport->FramebufferScale.x != 0.0f) ? viewport->FramebufferScale.x : g.IO.DisplayFramebufferScale.x; // == SetPixelDensity()
        }
        const bool backup_skip_items = window->SkipItems;
        window->SkipItems = false;
@@ -5308,6 +5308,7 @@ static ImDrawList* GetViewportBgFgDrawList(ImGuiViewportP* viewport, size_t draw
    if (viewport->BgFgDrawListsLastTimeActive[drawlist_no] != (float)g.Time)
    {
        draw_list->_ResetForNewFrame();
+        draw_list->_SetPixelDensity(viewport->FramebufferScale.x);
        draw_list->PushTexture(g.IO.Fonts->TexRef);
        draw_list->PushClipRect(viewport->Pos, viewport->Pos + viewport->Size, false);
        viewport->BgFgDrawListsLastTimeActive[drawlist_no] = (float)g.Time;
@@ -5591,7 +5592,6 @@ static void SetupDrawListSharedData()
        g.DrawListSharedData.InitialFlags |= ImDrawListFlags_AntiAliasedFill;
    if (g.IO.BackendFlags & ImGuiBackendFlags_RendererHasVtxOffset)
        g.DrawListSharedData.InitialFlags |= ImDrawListFlags_AllowVtxOffset;
-    g.DrawListSharedData.InitialFringeScale = 1.0f; // FIXME-DPI: Change this for some DPI scaling experiments.
 }

 void ImGui::NewFrame()
@@ -8081,6 +8081,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)

        // Setup draw list and outer clipping rectangle
        IM_ASSERT(window->DrawList->CmdBuffer.Size == 1 && window->DrawList->CmdBuffer[0].ElemCount == 0);
+        window->DrawList->_SetPixelDensity(window->Viewport->FramebufferScale.x);
        window->DrawList->PushTexture(g.Font->OwnerAtlas->TexRef);
        PushClipRect(host_rect.Min, host_rect.Max, false);

@@ -9049,7 +9050,7 @@ bool ImGui::IsRectVisible(const ImVec2& rect_min, const ImVec2& rect_max)
 // - UnregisterFontAtlas() [Internal]
 // - SetCurrentFont() [Internal]
 // - UpdateCurrentFontSize() [Internal]
-// - SetFontRasterizerDensity() [Internal]
+// - SetPixelDensity() [Internal]
 // - PushFont()
 // - PopFont()
 //-----------------------------------------------------------------------------
@@ -9242,7 +9243,7 @@ void ImGui::UpdateCurrentFontSize(float restore_font_size_after_scaling)
    final_size = GetRoundedFontSize(final_size);
    final_size = ImClamp(final_size, 1.0f, IMGUI_FONT_SIZE_MAX);
    if (g.Font != NULL && (g.IO.BackendFlags & ImGuiBackendFlags_RendererHasTextures))
-        g.Font->CurrentRasterizerDensity = g.FontRasterizerDensity;
+        g.Font->CurrentRasterizerDensity = g.CurrentPixelDensity;

    g.FontSize = final_size;
    g.DrawListSharedData.FontSize = g.FontSize;
@@ -9266,13 +9267,13 @@ void ImGui::UpdateCurrentFontSize(float restore_font_size_after_scaling)

 // Exposed in case user may want to override setting density.
 // IMPORTANT: Begin()/End() is overriding density. Be considerate of this you change it.
-void ImGui::SetFontRasterizerDensity(float rasterizer_density)
+void ImGui::SetPixelDensity(float pixel_density)
 {
    ImGuiContext& g = *GImGui;
    IM_ASSERT(g.IO.BackendFlags & ImGuiBackendFlags_RendererHasTextures);
-    if (g.FontRasterizerDensity == rasterizer_density)
+    if (g.CurrentPixelDensity == pixel_density)
        return;
-    g.FontRasterizerDensity = rasterizer_density;
+    g.CurrentPixelDensity = pixel_density;
    UpdateCurrentFontSize(0.0f);
 }

--- a/imgui.h
+++ b/imgui.h
@@ -3346,7 +3346,8 @@ struct ImDrawList
    ImVector<ImVec4>        _ClipRectStack;     // [Internal]
    ImVector<ImTextureRef>  _TextureStack;      // [Internal]
    ImVector<ImU8>          _CallbacksDataBuf;  // [Internal]
-    float                   _FringeScale;       // [Internal] anti-alias fringe is scaled by this value, this helps to keep things sharp while zooming at vertex buffer content
+    float                   _FringeScale;       // [Internal] anti-alias fringe is scaled by this value, this helps to keep things sharp while zooming at vertex buffer content.
+    float                   _InvFringeScale;    // [internal] 1.0 / _FringeScale // FIXME: Consider renaming to _PixelDensity.
    const char*             _OwnerName;         // Pointer to owner window's name for debugging

    // If you want to create ImDrawList instances, pass them ImGui::GetDrawListSharedData().
@@ -3480,6 +3481,7 @@ struct ImDrawList
    // [Internal helpers]
    IMGUI_API void  _SetDrawListSharedData(ImDrawListSharedData* data);
    IMGUI_API void  _ResetForNewFrame();
+    IMGUI_API void  _SetPixelDensity(float pixel_density);
    IMGUI_API void  _ClearFreeMemory();
    IMGUI_API void  _PopUnusedDrawCmd();
    IMGUI_API void  _TryMergeDrawCmds();
--- a/imgui_draw.cpp
+++ b/imgui_draw.cpp
@@ -396,7 +396,6 @@ void ImGui::StyleColorsLight(ImGuiStyle* dst)
 ImDrawListSharedData::ImDrawListSharedData()
 {
    memset((void*)this, 0, sizeof(*this));
-    InitialFringeScale = 1.0f;
    for (int i = 0; i < IM_COUNTOF(ArcFastVtx); i++)
    {
        const float a = ((float)i * 2 * IM_PI) / (float)IM_COUNTOF(ArcFastVtx);
@@ -473,7 +472,7 @@ void ImDrawList::_ResetForNewFrame()
    _Path.resize(0);
    _Splitter.Clear();
    CmdBuffer.push_back(ImDrawCmd());
-    _FringeScale = _Data->InitialFringeScale;
+    // Caller needs to bet _SetPixelDensity() as well.
 }

 void ImDrawList::_ClearFreeMemory()
@@ -655,6 +654,7 @@ void ImDrawList::_OnChangedVtxOffset()
 int ImDrawList::_CalcCircleAutoSegmentCount(float radius) const
 {
    // Automatic segment count
+    radius *= _InvFringeScale;
    const int radius_idx = (int)(radius + 0.999f); // ceil to never reduce accuracy
    if (radius_idx >= 0 && radius_idx < IM_COUNTOF(_Data->CircleSegmentCounts))
        return _Data->CircleSegmentCounts[radius_idx]; // Use cached value
@@ -720,6 +720,12 @@ void ImDrawList::_SetTexture(ImTextureRef tex_ref)
    _OnChangedTexture();
 }

+void ImDrawList::_SetPixelDensity(float pixel_density)
+{
+    _FringeScale = 1.0f / pixel_density;
+    _InvFringeScale = pixel_density;
+}
+
 // Reserve space for a number of vertices and indices.
 // You must finish filling your reserved data before calling PrimReserve() again, as it may reallocate or
 // submit the intermediate results. PrimUnreserve() can be used to release unused allocations.
@@ -1419,7 +1425,7 @@ void ImDrawList::PathBezierCubicCurveTo(const ImVec2& p2, const ImVec2& p3, cons
    if (num_segments == 0)
    {
        IM_ASSERT(_Data->CurveTessellationMaxError > 0.0f);
-        float max_error_sqr = _Data->CurveTessellationMaxError * _Data->CurveTessellationMaxError;
+        float max_error_sqr = (_Data->CurveTessellationMaxError * _FringeScale) * (_Data->CurveTessellationMaxError * _FringeScale);
        PathBezierCubicCurveToCasteljau(&_Path, p1.x, p1.y, p2.x, p2.y, p3.x, p3.y, p4.x, p4.y, max_error_sqr, 0); // Auto-tessellated
    }
    else
@@ -1436,7 +1442,7 @@ void ImDrawList::PathBezierQuadraticCurveTo(const ImVec2& p2, const ImVec2& p3,
    if (num_segments == 0)
    {
        IM_ASSERT(_Data->CurveTessellationMaxError > 0.0f);
-        float max_error_sqr = _Data->CurveTessellationMaxError * _Data->CurveTessellationMaxError;
+        float max_error_sqr = (_Data->CurveTessellationMaxError * _FringeScale) * (_Data->CurveTessellationMaxError * _FringeScale);
        PathBezierQuadraticCurveToCasteljau(&_Path, p1.x, p1.y, p2.x, p2.y, p3.x, p3.y, max_error_sqr, 0);// Auto-tessellated
    }
    else
--- a/imgui_internal.h
+++ b/imgui_internal.h
@@ -897,7 +897,6 @@ struct IMGUI_API ImDrawListSharedData
    float           FontScale;                  // Current font scale (== FontSize / Font->FontSize)
    float           CurveTessellationMaxError;  // Tessellation tolerance when using PathBezierCurveTo()
    float           CircleTessellationMaxError; // Number of circle segments to use per pixel of radius for AddCircle() etc
-    float           InitialFringeScale;         // Initial scale to apply to AA fringe
    ImDrawListFlags InitialFlags;               // Initial flags at the beginning of the frame (it is possible to alter flags on a per-drawlist basis afterwards)
    ImVec4          ClipRectFullscreen;         // Value for PushClipRectFullscreen()
    ImVector<ImVec2> TempBuffer;                // Temporary write buffer
@@ -2267,7 +2266,7 @@ struct ImGuiContext
    float                   FontSize;                           // Currently bound font size == line height (== FontSizeBase + externals scales applied in the UpdateCurrentFontSize() function).
    float                   FontSizeBase;                       // Font size before scaling == style.FontSizeBase == value passed to PushFont() when specified.
    float                   FontBakedScale;                     // == FontBaked->Size / FontSize. Scale factor over baked size. Rarely used nowadays, very often == 1.0f.
-    float                   FontRasterizerDensity;              // Current font density. Used by all calls to GetFontBaked().
+    float                   CurrentPixelDensity;                // Current font density. Used by all calls to GetFontBaked().
    float                   CurrentDpiScale;                    // Current window/viewport DpiScale == CurrentViewport->DpiScale
    ImDrawListSharedData    DrawListSharedData;
    ImGuiID                 WithinEndChildID;                   // Set within EndChild()
@@ -3390,8 +3389,8 @@ namespace ImGui
    IMGUI_API void          UnregisterFontAtlas(ImFontAtlas* atlas);
    IMGUI_API void          SetCurrentFont(ImFont* font, float font_size_before_scaling, float font_size_after_scaling);
    IMGUI_API void          UpdateCurrentFontSize(float restore_font_size_after_scaling);
-    IMGUI_API void          SetFontRasterizerDensity(float rasterizer_density);
-    inline float            GetFontRasterizerDensity() { return GImGui->FontRasterizerDensity; }
+    IMGUI_API void          SetPixelDensity(float pixel_density); // was SetFontRasterizerDensity()
+    inline float            GetPixelDensity() { return GImGui->CurrentPixelDensity; }
    inline float            GetRoundedFontSize(float size) { return IM_ROUND(size); }
    IMGUI_API ImFont*       GetDefaultFont();
    IMGUI_API void          PushPasswordFont();