Texture-based round corners: Adding style/drawlist flags for rounded corner textures

imgui.cpp

@@ -1070,6 +1070,7 @@ ImGuiStyle::ImGuiStyle()
     AntiAliasedLines        = true;             // Enable anti-aliased lines/borders. Disable if you are really tight on CPU/GPU.
     AntiAliasedLinesUseTex  = true;             // Enable anti-aliased lines/borders using textures where possible. Require backend to render with bilinear filtering.
     AntiAliasedFill         = true;             // Enable anti-aliased filled shapes (rounded rectangles, circles, etc.).
+    TexturedRoundCorners   = true;              // Enable using textures instead of strokes to draw rounded corners/circles where possible.
     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.
 
@@ -4297,6 +4298,8 @@ void ImGui::NewFrame()
         g.DrawListSharedData.InitialFlags |= ImDrawListFlags_AntiAliasedFill;
     if (g.IO.BackendFlags & ImGuiBackendFlags_RendererHasVtxOffset)
         g.DrawListSharedData.InitialFlags |= ImDrawListFlags_AllowVtxOffset;
+    if (g.Style.TexturedRoundCorners && !(g.Font->ContainerAtlas->Flags & ImFontAtlasFlags_NoBakedRoundCorners))
+        g.DrawListSharedData.InitialFlags |= ImDrawListFlags_TexturedRoundCorners;
 
     // Mark rendering data as invalid to prevent user who may have a handle on it to use it.
     for (int n = 0; n < g.Viewports.Size; n++)

imgui.h

@@ -1875,6 +1875,7 @@ struct ImGuiStyle
     bool        AntiAliasedLines;           // Enable anti-aliased lines/borders. Disable if you are really tight on CPU/GPU. Latched at the beginning of the frame (copied to ImDrawList).
     bool        AntiAliasedLinesUseTex;     // Enable anti-aliased lines/borders using textures where possible. Require backend to render with bilinear filtering. Latched at the beginning of the frame (copied to ImDrawList).
     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).
+    bool        TexturedRoundCorners;       // Enable using textures instead of strokes to draw rounded corners/circles where possible.
     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.
     ImVec4      Colors[ImGuiCol_COUNT];
@@ -2484,7 +2485,8 @@ enum ImDrawListFlags_
     ImDrawListFlags_AntiAliasedLines        = 1 << 0,  // Enable anti-aliased lines/borders (*2 the number of triangles for 1.0f wide line or lines thin enough to be drawn using textures, otherwise *3 the number of triangles)
     ImDrawListFlags_AntiAliasedLinesUseTex  = 1 << 1,  // Enable anti-aliased lines/borders using textures when possible. Require backend to render with bilinear filtering.
     ImDrawListFlags_AntiAliasedFill         = 1 << 2,  // Enable anti-aliased edge around filled shapes (rounded rectangles, circles).
-    ImDrawListFlags_AllowVtxOffset          = 1 << 3   // Can emit 'VtxOffset > 0' to allow large meshes. Set when 'ImGuiBackendFlags_RendererHasVtxOffset' is enabled.
+    ImDrawListFlags_AllowVtxOffset          = 1 << 3,  // Can emit 'VtxOffset > 0' to allow large meshes. Set when 'ImGuiBackendFlags_RendererHasVtxOffset' is enabled.
+    ImDrawListFlags_TexturedRoundCorners    = 1 << 4   // Enable using textures instead of strokes to draw rounded corners/circles where possible.
 };
 
 // Draw command list

imgui_demo.cpp

@@ -6399,6 +6399,7 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
             HelpMarker("Faster lines using texture data. Require backend to render with bilinear filtering (not point/nearest filtering).");
 
             ImGui::Checkbox("Anti-aliased fill", &style.AntiAliasedFill);
+            ImGui::Checkbox("Rounded corner textures", &style.TexturedRoundCorners);
             ImGui::PushItemWidth(ImGui::GetFontSize() * 8);
             ImGui::DragFloat("Curve Tessellation Tolerance", &style.CurveTessellationTol, 0.02f, 0.10f, 10.0f, "%.2f");
             if (style.CurveTessellationTol < 0.10f) style.CurveTessellationTol = 0.10f;

imgui_draw.cpp

@@ -1396,6 +1396,9 @@ void ImDrawList::AddLine(const ImVec2& p1, const ImVec2& p2, ImU32 col, float th
 // We are using the textures generated by ImFontAtlasBuildRenderRoundCornersTexData()
 inline bool AddRoundCornerRect(ImDrawList* draw_list, const ImVec2& a, const ImVec2& b, ImU32 col, float rounding, ImDrawFlags flags, bool fill)
 {
+    if (!(draw_list->Flags & ImDrawListFlags_TexturedRoundCorners)) // Disabled by the draw list flags
+        return false;
+
 #if 1
     flags = FixRectCornerFlags(flags);
     rounding = ImMin(rounding, ImFabs(b.x - a.x) * (((flags & ImDrawFlags_RoundCornersTop) == ImDrawFlags_RoundCornersTop) || ((flags & ImDrawFlags_RoundCornersBottom) == ImDrawFlags_RoundCornersBottom) ? 0.5f : 1.0f) - 1.0f);
@@ -1405,6 +1408,9 @@ inline bool AddRoundCornerRect(ImDrawList* draw_list, const ImVec2& a, const ImV
     const ImDrawListSharedData* data = draw_list->_Data;
     const int rad = (int)rounding;
 
+    if (data->Font->ContainerAtlas->Flags & ImFontAtlasFlags_NoBakedRoundCorners) // No data in font
+        return false;
+
     if ((rad <= 0) || // Zero radius causes issues with the [rad - 1] UV lookup below
         (rad > data->Font->ContainerAtlas->RoundCornersMaxSize))
     {
@@ -1414,9 +1420,7 @@ inline bool AddRoundCornerRect(ImDrawList* draw_list, const ImVec2& a, const ImV
 
     // Debug command to force this render path to only execute when shift is held
     if (!ImGui::GetIO().KeyShift)
-    {
         return false;
-    }
 
     ImTextureID tex_id = data->Font->ContainerAtlas->TexID;
     IM_ASSERT(tex_id == draw_list->_TextureIdStack.back());  // Use high-level ImGui::PushFont() or low-level ImDrawList::PushTextureId() to change font.
@@ -1773,10 +1777,16 @@ void ImDrawList::AddTriangleFilled(const ImVec2& p1, const ImVec2& p2, const ImV
 // (in which case the caller should try the regular circle drawing code)
 inline bool AddRoundCornerCircle(ImDrawList* draw_list, const ImVec2& center, float radius, ImU32 col, bool fill)
 {
+    if (!(draw_list->Flags & ImDrawListFlags_TexturedRoundCorners)) // Disabled by the draw list flags
+        return false;
+
     const ImDrawListSharedData* data = draw_list->_Data;
     ImTextureID tex_id = data->Font->ContainerAtlas->TexID;
     IM_ASSERT(tex_id == draw_list->_TextureIdStack.back());  // Use high-level ImGui::PushFont() or low-level ImDrawList::PushTextureId() to change font.
 
+    if (data->Font->ContainerAtlas->Flags & ImFontAtlasFlags_NoBakedRoundCorners) // No data in font
+        return false;
+
     const int rad = (int)radius;
     if (rad < 1 || rad > data->Font->ContainerAtlas->RoundCornersMaxSize) // Radius 0 will cause issues with the UV lookup below
         return false; // We can't handle this
@@ -2432,7 +2442,7 @@ ImFontAtlas::ImFontAtlas()
     TexGlyphPadding = 1;
     PackIdMouseCursors = PackIdLines = -1;
 
-    RoundCornersMaxSize = 60;
+    RoundCornersMaxSize = 32;
 }
 
 ImFontAtlas::~ImFontAtlas()