ImDrawFlags: rework/revert c2d6d26 + 39432bf in a way that is closer to old version and back to opt-in but with default 0 = all corners.

docs/CHANGELOG.txt

@@ -106,28 +106,29 @@ Other changes:
 Breaking Changes:
 
 - Removed redirecting functions/enums names that were marked obsolete in 1.66 (September 2018):
-  - ImGui::SetScrollHere() --> use ImGui::SetScrollHereY()
+    - ImGui::SetScrollHere() --> use ImGui::SetScrollHereY()
 - ImDrawList: upgraded AddPolyline()/PathStroke()'s "bool closed" parameter to use "ImDrawFlags flags".
+    - bool closed = false    --> use ImDrawFlags_None, or 0
+    - bool closed = true     --> use ImDrawFlags_Closed
   The matching ImDrawFlags_Closed value is guaranteed to always stay == 1 in the future.
-  - bool closed = false    --> use ImDrawFlags_None, or 0
-  - bool closed = true     --> use ImDrawFlags_Closed
   Difference may not be noticeable for most but zealous type-checking tools may report a need to change.
-- ImDrawList: upgraded AddRect(), AddRectFilled(), PathRect() to use general ImDrawFlags instead of ImDrawCornersFlags.
-  The old ImDrawCornersFlags used an awkward default value of ~0 or 0xF (4 lower bits set) to signify "round all
-  corners". We still support old flags, but note that the new named flags are opt-out instead of opt-in. [@rokups]
-  - AddRect(..., rounding, ImDrawCornerFlags_TopLeft) --> AddRect(..., ImDrawFlags_NoRoundCorners ^ ImDrawFlags_NoRoundCornerTL)
-  - Flags now sanely default to 0 instead of defaulting to ~0 or ImDrawCornerFlags_All, consistent with everywhere else.
-  - In practice, this shouldn't have an effect as those flags were rarely used.
-  - All meaningful old uses are supported:
-    - Default flags will behave the same.
-    - Use of old named flags will behave the same (but will be obsoleted later)
-    - Use of hardcoded ~0 or 0xF, previously suggested as a convenience, will behave the same (but will be obsoleted later).
-  - Not supported:
-    - Use of hardcoded values between 0x01 and 0x0E not using named flags are NOT supported (will assert).
-    - Use of new ImDrawFlags together with ImDrawCornerFlags in the same call (will assert).
-    - Use of rounding > 0.0f along old flags explicitely set as hardcoded 0 would have previously overidden the
-      rounding value back into "no rounding", whereas it will now behave as "round all corners".
-      This is technically the only real breaking change which we can't solve automatically.
+- ImDrawList: upgraded AddRect(), AddRectFilled(), PathRect() to use ImDrawFlags instead of ImDrawCornersFlags.
+    - ImDrawCornerFlags_TopLeft  --> use ImDrawFlags_RoundCornersTopLeft
+    - ImDrawCornerFlags_BotRight --> use ImDrawFlags_RoundCornersBottomRight
+    - ImDrawCornerFlags_None     --> use ImDrawFlags_RoundCornersNone etc.
+  Flags now sanely defaults to 0 instead of 0x0F, consistent with all other flags in the API.
+  IMPORTANT: The default with rounding > 0.0f is now "round all corners" vs old implicit "round no corners":
+    - rounding == 0.0f + flags == 0 --> meant no rounding  --> unchanged (common use)
+    - rounding  > 0.0f + flags != 0 --> meant rounding     --> unchanged (common use)
+    - rounding == 0.0f + flags != 0 --> meant no rounding  --> unchanged (unlikely use)
+    - rounding  > 0.0f + flags == 0 --> meant no rounding  --> BREAKING (unlikely use)!
+       - this ONLY matters for hardcoded use of 0 with rounding > 0.0f.
+       - fix by using named ImDrawFlags_RoundCornersNone or rounding == 0.0f!
+       - this is technically the only real breaking change which we can't solve automatically (it's also uncommon).
+  The old ImDrawCornersFlags used awkward default values of ~0 or 0xF (4 lower bits set) to signify "round all corners"
+  and we sometimes encouraged using them as shortcuts. As a result the legacy path still support use of hardcoded ~0
+  or any value from 0x1 or 0xF. They will behave the same with legacy paths enabled (will assert otherwise).
+  Courtesy of legacy untangling commity: [@rokups, @ocornut, @thedmd]
 - ImDrawList: clarified that PathArcTo()/PathArcToFast() won't render with radius < 0.0f. Previously it sorts
   of accidentally worked but would lead to counter-clockwise paths which and have an effect on anti-aliasing.
 - Moved 'misc/natvis/imgui.natvis' to 'misc/debuggers/imgui.natvis' as we will provide scripts for other debuggers.

imgui.cpp

@@ -386,23 +386,24 @@ CODE
  - 2021/XX/XX (1.XX) - Moved IME support functions from io.ImeSetInputScreenPosFn, io.ImeWindowHandle to the PlatformIO api.
 
 
- - 2021/03/11 (1.82) - upgraded ImDrawList::AddRect(), AddRectFilled(), PathRect() to use general ImDrawFlags instead of ImDrawCornersFlags.
-                       the old ImDrawCornersFlags used an awkward default value of ~0 or 0xF (4 lower bits set) to signify "round all corners". We still support old flags, but note that the new named flags are opt-out instead of opt-in!
-                        - AddRect(..., rounding, ImDrawCornerFlags_TopLeft) --> AddRect(..., ImDrawFlags_NoRoundCorners ^ ImDrawFlags_NoRoundCornerTL)
-                       flags now sanely defaults to 0 instead of defaulting to ~0 or ImDrawCornerFlags_All, consistent with everywhere else in the codebase.
-                       in practice, this shouldn't have an effect as those flags were rarely used. all meaningful old uses are supported:
-                        - default flags will behave the same.
-                        - use of old named flags will behave the same (but will be obsoleted later).
-                        - use of hardcoded ~0 or 0xF, previously suggested as a convenience, will behave the same (but will be obsoleted later).
-                       not supported:
-                        - use of hardcoded values between 0x01 and 0x0E not using named flags are NOT supported (will assert).
-                        - use of new ImDrawFlags together with ImDrawCornerFlags in the same call (will assert).
-                        - use of rounding > 0.0f along old flags explicitely set as hard coded 0 would have previously overidden the rounding value back into "no rounding", whereas it will now behave as "round all corners". This is technically the only real breaking change which we can't solve automatically.
+ - 2021/03/12 (1.82) - upgraded ImDrawList::AddRect(), AddRectFilled(), PathRect() to use ImDrawFlags instead of ImDrawCornersFlags.
+                        - ImDrawCornerFlags_TopLeft  -> use ImDrawFlags_RoundCornersTopLeft
+                        - ImDrawCornerFlags_BotRight -> use ImDrawFlags_RoundCornersBottomRight
+                        - ImDrawCornerFlags_None     -> use ImDrawFlags_RoundCornersNone etc.
+                       flags now sanely defaults to 0 instead of 0x0F, consistent with all other flags in the API.
+                       breaking: the default with rounding > 0.0f is now "round all corners" vs old implicit "round no corners":
+                        - rounding == 0.0f + flags == 0 --> meant no rounding  --> unchanged (common use)
+                        - rounding  > 0.0f + flags != 0 --> meant rounding     --> unchanged (common use)
+                        - rounding == 0.0f + flags != 0 --> meant no rounding  --> unchanged (unlikely use)
+                        - rounding  > 0.0f + flags == 0 --> meant no rounding  --> BREAKING (unlikely use): will now round all corners --> use ImDrawFlags_RoundCornersNone or rounding == 0.0f.
+                       this ONLY matters for hard coded use of 0 + rounding > 0.0f. Use of named ImDrawFlags_RoundCornersNone (new) or ImDrawCornerFlags_None (old) are ok.
+                       the old ImDrawCornersFlags used awkward default values of ~0 or 0xF (4 lower bits set) to signify "round all corners" and we sometimes encouraged using them as shortcuts.
+                       legacy path still support use of hard coded ~0 or any value from 0x1 or 0xF. They will behave the same with legacy paths enabled (will assert otherwise).
  - 2021/03/11 (1.82) - removed redirecting functions/enums names that were marked obsolete in 1.66 (September 2018):
                         - ImGui::SetScrollHere()              -> use ImGui::SetScrollHereY()
  - 2021/03/11 (1.82) - clarified that ImDrawList::PathArcTo(), ImDrawList::PathArcToFast() won't render with radius < 0.0f. Previously it sorts of accidentally worked but would generally lead to counter-clockwise paths and have an effect on anti-aliasing.
  - 2021/03/10 (1.82) - upgraded ImDrawList::AddPolyline() and PathStroke() "bool closed" parameter to "ImDrawFlags flags". The matching ImDrawFlags_Closed value is guaranteed to always stay == 1 in the future.
->- 2021/02/22 (1.82) - win32+mingw: Re-enabled IME functions by default even under MinGW. In July 2016, issue #738 had me incorrectly disable those default functions for MinGW. MinGW users should: either link with -limm32, either set their imconfig file  with '#define IMGUI_DISABLE_WIN32_DEFAULT_IME_FUNCTIONS'.
+ - 2021/02/22 (1.82) - win32+mingw: Re-enabled IME functions by default even under MinGW. In July 2016, issue #738 had me incorrectly disable those default functions for MinGW. MinGW users should: either link with -limm32, either set their imconfig file  with '#define IMGUI_DISABLE_WIN32_DEFAULT_IME_FUNCTIONS'.
  - 2021/02/17 (1.82) - renamed rarely used style.CircleSegmentMaxError (old default = 1.60f) to style.CircleTessellationMaxError (new default = 0.30f) as the meaning of the value changed.
  - 2021/02/03 (1.81) - renamed ListBoxHeader(const char* label, ImVec2 size) to BeginListBox(). Kept inline redirection function (will obsolete).
                      - removed ListBoxHeader(const char* label, int items_count, int height_in_items = -1) in favor of specifying size. Kept inline redirection function (will obsolete).
@@ -5840,7 +5841,7 @@ void ImGui::RenderWindowDecorations(ImGuiWindow* window, const ImRect& title_bar
                 if (override_alpha)
                     bg_col = (bg_col & ~IM_COL32_A_MASK) | (IM_F32_TO_INT8_SAT(alpha) << IM_COL32_A_SHIFT);
             }
-            window->DrawList->AddRectFilled(window->Pos + ImVec2(0, window->TitleBarHeight()), window->Pos + window->Size, bg_col, window_rounding, (flags & ImGuiWindowFlags_NoTitleBar) ? 0 : ImDrawFlags_NoRoundCornerT);
+            window->DrawList->AddRectFilled(window->Pos + ImVec2(0, window->TitleBarHeight()), window->Pos + window->Size, bg_col, window_rounding, (flags & ImGuiWindowFlags_NoTitleBar) ? 0 : ImDrawFlags_RoundCornersBottom);
         }
 
         // Title bar
@@ -5849,7 +5850,7 @@ void ImGui::RenderWindowDecorations(ImGuiWindow* window, const ImRect& title_bar
         if (!(flags & ImGuiWindowFlags_NoTitleBar) && !window->DockIsActive)
         {
             ImU32 title_bar_col = GetColorU32(title_bar_is_highlight ? ImGuiCol_TitleBgActive : ImGuiCol_TitleBg);
-            window->DrawList->AddRectFilled(title_bar_rect.Min, title_bar_rect.Max, title_bar_col, window_rounding, ImDrawFlags_NoRoundCornerB);
+            window->DrawList->AddRectFilled(title_bar_rect.Min, title_bar_rect.Max, title_bar_col, window_rounding, ImDrawFlags_RoundCornersTop);
         }
 
         // Menu bar
@@ -5857,7 +5858,7 @@ void ImGui::RenderWindowDecorations(ImGuiWindow* window, const ImRect& title_bar
         {
             ImRect menu_bar_rect = window->MenuBarRect();
             menu_bar_rect.ClipWith(window->Rect());  // Soft clipping, in particular child window don't have minimum size covering the menu bar so this is useful for them.
-            window->DrawList->AddRectFilled(menu_bar_rect.Min + ImVec2(window_border_size, 0), menu_bar_rect.Max - ImVec2(window_border_size, 0), GetColorU32(ImGuiCol_MenuBarBg), (flags & ImGuiWindowFlags_NoTitleBar) ? window_rounding : 0.0f, ImDrawFlags_NoRoundCornerB);
+            window->DrawList->AddRectFilled(menu_bar_rect.Min + ImVec2(window_border_size, 0), menu_bar_rect.Max - ImVec2(window_border_size, 0), GetColorU32(ImGuiCol_MenuBarBg), (flags & ImGuiWindowFlags_NoTitleBar) ? window_rounding : 0.0f, ImDrawFlags_RoundCornersTop);
             if (style.FrameBorderSize > 0.0f && menu_bar_rect.Max.y < window->Pos.y + window->Size.y)
                 window->DrawList->AddLine(menu_bar_rect.GetBL(), menu_bar_rect.GetBR(), GetColorU32(ImGuiCol_Border), style.FrameBorderSize);
         }

imgui.h

@@ -2380,24 +2380,23 @@ struct ImDrawListSplitter
 };
 
 // Flags for ImDrawList functions
-// (Before version 1.82: functions like AddRect(), AddRectFilled(), AddImageRounded(), PathRect() used ImDrawCornerFlags,
-//  we have moved those in 1.82 to ImDrawList but using opposite "opt-out" logic instead of "opt-in" logic:
-//    Old: ImDrawCornerFlags_BotLeft          New: ImDrawFlags_NoRoundCornerBL
-//  The old enums are defined under ImDrawCornerFlags_ in the "Obsolete functions and types" section of this header)
-// (Legacy: bit 0 must always correspond to ImDrawFlags_Closed to be backward compatible with old API using a bool. Bits 1..3 must b unused)
+// (Legacy: bit 0 must always correspond to ImDrawFlags_Closed to be backward compatible with old API using a bool. Bits 1..3 must be unused)
 enum ImDrawFlags_
 {
     ImDrawFlags_None                        = 0,
     ImDrawFlags_Closed                      = 1 << 0, // PathStroke(), AddPolyline(): specify that shape should be closed (Important: this is always == 1 for legacy reason)
-    ImDrawFlags_NoRoundCornerTL             = 1 << 4, // AddRect(), AddRectFilled(), PathRect(): disable rounding top-left corner when rounding > 0.0f
-    ImDrawFlags_NoRoundCornerTR             = 1 << 5, // AddRect(), AddRectFilled(), PathRect(): disable rounding top-right corner when rounding > 0.0f
-    ImDrawFlags_NoRoundCornerBL             = 1 << 6, // AddRect(), AddRectFilled(), PathRect(): disable rounding bottom-left corner when rounding > 0.0f
-    ImDrawFlags_NoRoundCornerBR             = 1 << 7, // AddRect(), AddRectFilled(), PathRect(): disable rounding bottom-right corner when rounding > 0.0f
-    ImDrawFlags_NoRoundCornerT              = ImDrawFlags_NoRoundCornerTL | ImDrawFlags_NoRoundCornerTR,
-    ImDrawFlags_NoRoundCornerR              = ImDrawFlags_NoRoundCornerTR | ImDrawFlags_NoRoundCornerBR,
-    ImDrawFlags_NoRoundCornerL              = ImDrawFlags_NoRoundCornerTL | ImDrawFlags_NoRoundCornerBL,
-    ImDrawFlags_NoRoundCornerB              = ImDrawFlags_NoRoundCornerBL | ImDrawFlags_NoRoundCornerBR,
-    ImDrawFlags_NoRoundCorners              = ImDrawFlags_NoRoundCornerTL | ImDrawFlags_NoRoundCornerTR | ImDrawFlags_NoRoundCornerBL | ImDrawFlags_NoRoundCornerBR
+    ImDrawFlags_RoundCornersTopLeft         = 1 << 4, // AddRect(), AddRectFilled(), PathRect(): enable rounding top-left corner only (when rounding > 0.0f, we default to all corners). Was 0x01.
+    ImDrawFlags_RoundCornersTopRight        = 1 << 5, // AddRect(), AddRectFilled(), PathRect(): enable rounding top-right corner only (when rounding > 0.0f, we default to all corners). Was 0x02.
+    ImDrawFlags_RoundCornersBottomLeft      = 1 << 6, // AddRect(), AddRectFilled(), PathRect(): enable rounding bottom-left corner only (when rounding > 0.0f, we default to all corners). Was 0x04.
+    ImDrawFlags_RoundCornersBottomRight     = 1 << 7, // AddRect(), AddRectFilled(), PathRect(): enable rounding bottom-right corner only (when rounding > 0.0f, we default to all corners). Wax 0x08.
+    ImDrawFlags_RoundCornersNone            = 1 << 8, // AddRect(), AddRectFilled(), PathRect(): disable rounding on all corners (when rounding > 0.0f). This is NOT zero, NOT an implicit flag!
+    ImDrawFlags_RoundCornersTop             = ImDrawFlags_RoundCornersTopLeft | ImDrawFlags_RoundCornersTopRight,
+    ImDrawFlags_RoundCornersBottom          = ImDrawFlags_RoundCornersBottomLeft | ImDrawFlags_RoundCornersBottomRight,
+    ImDrawFlags_RoundCornersLeft            = ImDrawFlags_RoundCornersBottomLeft | ImDrawFlags_RoundCornersTopLeft,
+    ImDrawFlags_RoundCornersRight           = ImDrawFlags_RoundCornersBottomRight | ImDrawFlags_RoundCornersTopRight,
+    ImDrawFlags_RoundCornersAll             = ImDrawFlags_RoundCornersTopLeft | ImDrawFlags_RoundCornersTopRight | ImDrawFlags_RoundCornersBottomLeft | ImDrawFlags_RoundCornersBottomRight,
+    ImDrawFlags_RoundCornersDefault_        = ImDrawFlags_RoundCornersAll, // Default to ALL corners if none of the _RoundCornersXX flags are specified.
+    ImDrawFlags_RoundCornersMask_           = ImDrawFlags_RoundCornersAll | ImDrawFlags_RoundCornersNone
 };
 
 // Flags for ImDrawList instance. Those are set automatically by ImGui:: functions from ImGuiIO settings, and generally not manipulated directly.
@@ -3044,12 +3043,12 @@ namespace ImGui
 typedef ImDrawFlags ImDrawCornerFlags;
 enum ImDrawCornerFlags_
 {
-    ImDrawCornerFlags_None      = ImDrawFlags_NoRoundCorners,
-    ImDrawCornerFlags_TopLeft   = 1 << 24,  // Was (1 << 0) prior to 1.82. Order matches ImDrawFlags_NoRoundCorner* flag (we exploit this internally).
-    ImDrawCornerFlags_TopRight  = 1 << 25,  // Was (1 << 1) prior to 1.82.
-    ImDrawCornerFlags_BotLeft   = 1 << 26,  // Was (1 << 2) prior to 1.82.
-    ImDrawCornerFlags_BotRight  = 1 << 27,  // Was (1 << 3) prior to 1.82.
-    ImDrawCornerFlags_All       = ImDrawCornerFlags_TopLeft | ImDrawCornerFlags_TopRight | ImDrawCornerFlags_BotLeft | ImDrawCornerFlags_BotRight, // Was (0x0F) prior to 1.82
+    ImDrawCornerFlags_None      = ImDrawFlags_RoundCornersNone,         // Was == 0 prior to 1.82, this is now == ImDrawFlags_RoundCornersNone which is != 0 and not implicit
+    ImDrawCornerFlags_TopLeft   = ImDrawFlags_RoundCornersTopLeft,      // Was == 0x01 (1 << 0) prior to 1.82. Order matches ImDrawFlags_NoRoundCorner* flag (we exploit this internally).
+    ImDrawCornerFlags_TopRight  = ImDrawFlags_RoundCornersTopRight,     // Was == 0x02 (1 << 1) prior to 1.82.
+    ImDrawCornerFlags_BotLeft   = ImDrawFlags_RoundCornersBottomLeft,   // Was == 0x04 (1 << 2) prior to 1.82.
+    ImDrawCornerFlags_BotRight  = ImDrawFlags_RoundCornersBottomRight,  // Was == 0x08 (1 << 3) prior to 1.82.
+    ImDrawCornerFlags_All       = ImDrawFlags_RoundCornersAll,          // Was == 0x0F prior to 1.82
     ImDrawCornerFlags_Top       = ImDrawCornerFlags_TopLeft | ImDrawCornerFlags_TopRight,
     ImDrawCornerFlags_Bot       = ImDrawCornerFlags_BotLeft | ImDrawCornerFlags_BotRight,
     ImDrawCornerFlags_Left      = ImDrawCornerFlags_TopLeft | ImDrawCornerFlags_BotLeft,

imgui_demo.cpp

@@ -7286,7 +7286,7 @@ static void ShowExampleAppCustomRendering(bool* p_open)
             const ImVec2 p = ImGui::GetCursorScreenPos();
             const ImU32 col = ImColor(colf);
             const float spacing = 10.0f;
-            const ImDrawFlags corners_tl_br = ImDrawFlags_NoRoundCornerTR | ImDrawFlags_NoRoundCornerBL;
+            const ImDrawFlags corners_tl_br = ImDrawFlags_RoundCornersTopLeft | ImDrawFlags_RoundCornersBottomRight;
             const float rounding = sz / 5.0f;
             const int circle_segments = circle_segments_override ? circle_segments_override_v : 0;
             const int curve_segments = curve_segments_override ? curve_segments_override_v : 0;

imgui_draw.cpp

@@ -1285,39 +1285,47 @@ void ImDrawList::PathBezierQuadraticCurveTo(const ImVec2& p2, const ImVec2& p3,
     }
 }
 
-#ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
-static inline ImDrawFlags FixDrawCornerFlags(ImDrawFlags flags)
+IM_STATIC_ASSERT(ImDrawFlags_RoundCornersTopLeft == (1 << 4));
+static inline ImDrawFlags FixRectCornerFlags(ImDrawFlags flags)
 {
-    // If any of following asserts triggers, please update your code replacing all uses of ImDrawCornerFlags_* with ImDrawFlags_*.
-    // Legacy Rule 1: Support for hard coded 0x0F or ~0 (used to be equivalent to ImDrawCornerFlags_All)
-    if (flags == ~0 || flags == 0x0F)
-        return 0;
+#ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
+    // Legacy Support for hard coded ~0 (used to be a suggested equivalent to ImDrawCornerFlags_All)
+    //   ~0   --> ImDrawFlags_RoundCornersAll or 0
+    if (flags == ~0)
+        return ImDrawFlags_RoundCornersAll;
+
+    // Legacy Support for hard coded 0x01 to 0x0F (matching 15 out of 16 old flags combinations)
+    //   0x01 --> ImDrawFlags_RoundCornersTopLeft (VALUE 0x01 OVERLAPS ImDrawFlags_Closed but ImDrawFlags_Closed is never valid in this path!)
+    //   0x02 --> ImDrawFlags_RoundCornersTopRight
+    //   0x03 --> ImDrawFlags_RoundCornersTopLeft | ImDrawFlags_RoundCornersTopRight
+    //   0x04 --> ImDrawFlags_RoundCornersBotLeft
+    //   0x05 --> ImDrawFlags_RoundCornersTopLeft | ImDrawFlags_RoundCornersBotLeft
+    //   ...
+    //   0x0F --> ImDrawFlags_RoundCornersAll or 0
+    // (See all values in ImDrawCornerFlags_)
+    if (flags >= 0x01 && flags <= 0x0F)
+        return (flags << 4);
+
+    // We cannot support hard coded 0x00 with 'float rounding > 0.0f' --> replace with ImDrawFlags_RoundCornersNone or use 'float rounding = 0.0f'
+#endif
 
-    // Legacy Rule 2: if any of old ImDrawCornerFlags flags, move them to corresponding positions of non-legacy flags and invert them.
-    if ((flags & ImDrawCornerFlags_All) != 0)
-    {
-        IM_ASSERT((flags & ~ImDrawCornerFlags_All) == 0 && "Mixing legacy ImDrawCornerFlags and new ImDrawFlags is not allowed.");
-        IM_STATIC_ASSERT((ImDrawCornerFlags_TopLeft >> 20) == ImDrawFlags_NoRoundCornerTL);
-        return (flags >> 20) ^ ImDrawFlags_NoRoundCorners;
-    }
+    // If this triggers, please update your code replacing hardcoded values with new ImDrawFlags_RoundCorners* values.
+    // Note that ImDrawFlags_Closed (== 0x01) is an invalid flag for AddRect(), AddRectFilled(), PathRect() etc...
+    IM_ASSERT((flags & 0x0F) == 0 && "Misuse of legacy hardcoded ImDrawCornerFlags values!");
+
+    if ((flags & ImDrawFlags_RoundCornersMask_) == 0)
+        flags |= ImDrawFlags_RoundCornersAll;
 
-    // Bits 1..3 are unused, did you use old hard coded values?! In which case, check the old values in ImDrawCornerFlags_ definition.
-    // If you used ~0 or 0x0F you can now change them to 0 or ImDrawFlags_None.
-    IM_ASSERT((flags & 0x0E) == 0);
     return flags;
 }
-#else
-// Assert and return same value
-#define FixDrawCornerFlags(FLAGS)  (IM_ASSERT((FLAGS & 0x0E) == 0), FLAGS)
-#endif
 
 void ImDrawList::PathRect(const ImVec2& a, const ImVec2& b, float rounding, ImDrawFlags flags)
 {
-    flags = FixDrawCornerFlags(flags);
-    rounding = ImMin(rounding, ImFabs(b.x - a.x) * ( ((flags & ImDrawFlags_NoRoundCornerT) == 0) || ((flags & ImDrawFlags_NoRoundCornerB) == 0) ? 0.5f : 1.0f ) - 1.0f);
-    rounding = ImMin(rounding, ImFabs(b.y - a.y) * ( ((flags & ImDrawFlags_NoRoundCornerL) == 0) || ((flags & ImDrawFlags_NoRoundCornerR) == 0) ? 0.5f : 1.0f ) - 1.0f);
+    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);
+    rounding = ImMin(rounding, ImFabs(b.y - a.y) * ( ((flags & ImDrawFlags_RoundCornersLeft) == ImDrawFlags_RoundCornersLeft) || ((flags & ImDrawFlags_RoundCornersRight)  == ImDrawFlags_RoundCornersRight)  ? 0.5f : 1.0f ) - 1.0f);
 
-    if (rounding <= 0.0f || (flags & ImDrawFlags_NoRoundCorners) == ImDrawFlags_NoRoundCorners)
+    if (rounding <= 0.0f || (flags & ImDrawFlags_RoundCornersMask_) == ImDrawFlags_RoundCornersNone)
     {
         PathLineTo(a);
         PathLineTo(ImVec2(b.x, a.y));
@@ -1326,10 +1334,10 @@ void ImDrawList::PathRect(const ImVec2& a, const ImVec2& b, float rounding, ImDr
     }
     else
     {
-        const float rounding_tl = (flags & ImDrawFlags_NoRoundCornerTL) ? 0.0f : rounding;
-        const float rounding_tr = (flags & ImDrawFlags_NoRoundCornerTR) ? 0.0f : rounding;
-        const float rounding_br = (flags & ImDrawFlags_NoRoundCornerBR) ? 0.0f : rounding;
-        const float rounding_bl = (flags & ImDrawFlags_NoRoundCornerBL) ? 0.0f : rounding;
+        const float rounding_tl = (flags & ImDrawFlags_RoundCornersTopLeft)     ? rounding : 0.0f;
+        const float rounding_tr = (flags & ImDrawFlags_RoundCornersTopRight)    ? rounding : 0.0f;
+        const float rounding_br = (flags & ImDrawFlags_RoundCornersBottomRight) ? rounding : 0.0f;
+        const float rounding_bl = (flags & ImDrawFlags_RoundCornersBottomLeft)  ? rounding : 0.0f;
         PathArcToFast(ImVec2(a.x + rounding_tl, a.y + rounding_tl), rounding_tl, 6, 9);
         PathArcToFast(ImVec2(b.x - rounding_tr, a.y + rounding_tr), rounding_tr, 9, 12);
         PathArcToFast(ImVec2(b.x - rounding_br, b.y - rounding_br), rounding_br, 0, 3);
@@ -1363,15 +1371,15 @@ void ImDrawList::AddRectFilled(const ImVec2& p_min, const ImVec2& p_max, ImU32 c
 {
     if ((col & IM_COL32_A_MASK) == 0)
         return;
-    if (rounding > 0.0f && (flags & ImDrawFlags_NoRoundCorners) != ImDrawFlags_NoRoundCorners)
+    if (rounding <= 0.0f || (flags & ImDrawFlags_RoundCornersMask_) == ImDrawFlags_RoundCornersNone)
     {
-        PathRect(p_min, p_max, rounding, flags);
-        PathFillConvex(col);
+        PrimReserve(6, 4);
+        PrimRect(p_min, p_max, col);
     }
     else
     {
-        PrimReserve(6, 4);
-        PrimRect(p_min, p_max, col);
+        PathRect(p_min, p_max, rounding, flags);
+        PathFillConvex(col);
     }
 }
 
@@ -1606,8 +1614,8 @@ void ImDrawList::AddImageRounded(ImTextureID user_texture_id, const ImVec2& p_mi
     if ((col & IM_COL32_A_MASK) == 0)
         return;
 
-    flags = FixDrawCornerFlags(flags);
-    if (rounding <= 0.0f || (flags & ImDrawFlags_NoRoundCorners) == ImDrawFlags_NoRoundCorners)
+    flags = FixRectCornerFlags(flags);
+    if (rounding <= 0.0f || (flags & ImDrawFlags_RoundCornersMask_) == ImDrawFlags_RoundCornersNone)
     {
         AddImage(user_texture_id, p_min, p_max, uv_min, uv_max, col);
         return;
@@ -3858,14 +3866,14 @@ void ImGui::RenderRectFilledWithHole(ImDrawList* draw_list, ImRect outer, ImRect
     const bool fill_R = (inner.Max.x < outer.Max.x);
     const bool fill_U = (inner.Min.y > outer.Min.y);
     const bool fill_D = (inner.Max.y < outer.Max.y);
-    if (fill_L) draw_list->AddRectFilled(ImVec2(outer.Min.x, inner.Min.y), ImVec2(inner.Min.x, inner.Max.y), col, rounding, (fill_U ? ImDrawFlags_NoRoundCornerTL : 0) | (fill_D ? ImDrawFlags_NoRoundCornerBL : 0));
-    if (fill_R) draw_list->AddRectFilled(ImVec2(inner.Max.x, inner.Min.y), ImVec2(outer.Max.x, inner.Max.y), col, rounding, (fill_U ? ImDrawFlags_NoRoundCornerTR : 0) | (fill_D ? ImDrawFlags_NoRoundCornerBR : 0));
-    if (fill_U) draw_list->AddRectFilled(ImVec2(inner.Min.x, outer.Min.y), ImVec2(inner.Max.x, inner.Min.y), col, rounding, (fill_L ? ImDrawFlags_NoRoundCornerTL : 0) | (fill_R ? ImDrawFlags_NoRoundCornerTR : 0));
-    if (fill_D) draw_list->AddRectFilled(ImVec2(inner.Min.x, inner.Max.y), ImVec2(inner.Max.x, outer.Max.y), col, rounding, (fill_L ? ImDrawFlags_NoRoundCornerBL : 0) | (fill_R ? ImDrawFlags_NoRoundCornerBR : 0));
-    if (fill_L && fill_U) draw_list->AddRectFilled(ImVec2(outer.Min.x, outer.Min.y), ImVec2(inner.Min.x, inner.Min.y), col, rounding, ImDrawFlags_NoRoundCornerB | ImDrawFlags_NoRoundCornerTR);
-    if (fill_R && fill_U) draw_list->AddRectFilled(ImVec2(inner.Max.x, outer.Min.y), ImVec2(outer.Max.x, inner.Min.y), col, rounding, ImDrawFlags_NoRoundCornerB | ImDrawFlags_NoRoundCornerTL);
-    if (fill_L && fill_D) draw_list->AddRectFilled(ImVec2(outer.Min.x, inner.Max.y), ImVec2(inner.Min.x, outer.Max.y), col, rounding, ImDrawFlags_NoRoundCornerT | ImDrawFlags_NoRoundCornerBR);
-    if (fill_R && fill_D) draw_list->AddRectFilled(ImVec2(inner.Max.x, inner.Max.y), ImVec2(outer.Max.x, outer.Max.y), col, rounding, ImDrawFlags_NoRoundCornerT | ImDrawFlags_NoRoundCornerBL);
+    if (fill_L) draw_list->AddRectFilled(ImVec2(outer.Min.x, inner.Min.y), ImVec2(inner.Min.x, inner.Max.y), col, rounding, (fill_U ? 0 : ImDrawFlags_RoundCornersTopLeft)  | (fill_D ? 0 : ImDrawFlags_RoundCornersBottomLeft));
+    if (fill_R) draw_list->AddRectFilled(ImVec2(inner.Max.x, inner.Min.y), ImVec2(outer.Max.x, inner.Max.y), col, rounding, (fill_U ? 0 : ImDrawFlags_RoundCornersTopRight) | (fill_D ? 0 : ImDrawFlags_RoundCornersBottomRight));
+    if (fill_U) draw_list->AddRectFilled(ImVec2(inner.Min.x, outer.Min.y), ImVec2(inner.Max.x, inner.Min.y), col, rounding, (fill_L ? 0 : ImDrawFlags_RoundCornersTopLeft)  | (fill_R ? 0 : ImDrawFlags_RoundCornersTopRight));
+    if (fill_D) draw_list->AddRectFilled(ImVec2(inner.Min.x, inner.Max.y), ImVec2(inner.Max.x, outer.Max.y), col, rounding, (fill_L ? 0 : ImDrawFlags_RoundCornersBottomLeft)  | (fill_R ? 0 : ImDrawFlags_RoundCornersBottomRight));
+    if (fill_L && fill_U) draw_list->AddRectFilled(ImVec2(outer.Min.x, outer.Min.y), ImVec2(inner.Min.x, inner.Min.y), col, rounding, ImDrawFlags_RoundCornersTopLeft);
+    if (fill_R && fill_U) draw_list->AddRectFilled(ImVec2(inner.Max.x, outer.Min.y), ImVec2(outer.Max.x, inner.Min.y), col, rounding, ImDrawFlags_RoundCornersTopRight);
+    if (fill_L && fill_D) draw_list->AddRectFilled(ImVec2(outer.Min.x, inner.Max.y), ImVec2(inner.Min.x, outer.Max.y), col, rounding, ImDrawFlags_RoundCornersBottomLeft);
+    if (fill_R && fill_D) draw_list->AddRectFilled(ImVec2(inner.Max.x, inner.Max.y), ImVec2(outer.Max.x, outer.Max.y), col, rounding, ImDrawFlags_RoundCornersBottomRight);
 }
 
 // Helper for ColorPicker4()
@@ -3874,10 +3882,12 @@ void ImGui::RenderRectFilledWithHole(ImDrawList* draw_list, ImRect outer, ImRect
 // FIXME: uses ImGui::GetColorU32
 void ImGui::RenderColorRectWithAlphaCheckerboard(ImDrawList* draw_list, ImVec2 p_min, ImVec2 p_max, ImU32 col, float grid_step, ImVec2 grid_off, float rounding, ImDrawFlags flags)
 {
+    if ((flags & ImDrawFlags_RoundCornersMask_) == 0)
+        flags = ImDrawFlags_RoundCornersDefault_;
     if (((col & IM_COL32_A_MASK) >> IM_COL32_A_SHIFT) < 0xFF)
     {
-        ImU32 col_bg1 = ImGui::GetColorU32(ImAlphaBlendColors(IM_COL32(204, 204, 204, 255), col));
-        ImU32 col_bg2 = ImGui::GetColorU32(ImAlphaBlendColors(IM_COL32(128, 128, 128, 255), col));
+        ImU32 col_bg1 = GetColorU32(ImAlphaBlendColors(IM_COL32(204, 204, 204, 255), col));
+        ImU32 col_bg2 = GetColorU32(ImAlphaBlendColors(IM_COL32(128, 128, 128, 255), col));
         draw_list->AddRectFilled(p_min, p_max, col_bg1, rounding, flags);
 
         int yi = 0;
@@ -3891,10 +3901,12 @@ void ImGui::RenderColorRectWithAlphaCheckerboard(ImDrawList* draw_list, ImVec2 p
                 float x1 = ImClamp(x, p_min.x, p_max.x), x2 = ImMin(x + grid_step, p_max.x);
                 if (x2 <= x1)
                     continue;
-                ImDrawFlags cell_flags = ImDrawFlags_NoRoundCorners;
-                if (y1 <= p_min.y) { if (x1 <= p_min.x) cell_flags &= ~ImDrawFlags_NoRoundCornerTL; if (x2 >= p_max.x) cell_flags &= ~ImDrawFlags_NoRoundCornerTR; }
-                if (y2 >= p_max.y) { if (x1 <= p_min.x) cell_flags &= ~ImDrawFlags_NoRoundCornerBL; if (x2 >= p_max.x) cell_flags &= ~ImDrawFlags_NoRoundCornerBR; }
-                cell_flags |= flags;
+                ImDrawFlags cell_flags = ImDrawFlags_RoundCornersNone;
+                if (y1 <= p_min.y) { if (x1 <= p_min.x) cell_flags |= ImDrawFlags_RoundCornersTopLeft; if (x2 >= p_max.x) cell_flags |= ImDrawFlags_RoundCornersTopRight; }
+                if (y2 >= p_max.y) { if (x1 <= p_min.x) cell_flags |= ImDrawFlags_RoundCornersBottomLeft; if (x2 >= p_max.x) cell_flags |= ImDrawFlags_RoundCornersBottomRight; }
+
+                // Combine flags
+                cell_flags = (flags == ImDrawFlags_RoundCornersNone || cell_flags == ImDrawFlags_RoundCornersNone) ? ImDrawFlags_RoundCornersNone : (cell_flags & flags);
                 draw_list->AddRectFilled(ImVec2(x1, y1), ImVec2(x2, y2), col_bg2, rounding, cell_flags);
             }
         }

imgui_widgets.cpp

@@ -881,19 +881,19 @@ void ImGui::Scrollbar(ImGuiAxis axis)
 
     // Calculate scrollbar bounding box
     ImRect bb = GetWindowScrollbarRect(window, axis);
-    ImDrawFlags rounding_corners = ImDrawFlags_NoRoundCorners;
+    ImDrawFlags rounding_corners = ImDrawFlags_RoundCornersNone;
     if (axis == ImGuiAxis_X)
     {
-        rounding_corners &= ~ImDrawFlags_NoRoundCornerBL;
+        rounding_corners |= ImDrawFlags_RoundCornersBottomLeft;
         if (!window->ScrollbarY)
-            rounding_corners &= ~ImDrawFlags_NoRoundCornerBR;
+            rounding_corners |= ImDrawFlags_RoundCornersBottomRight;
     }
     else
     {
         if ((window->Flags & ImGuiWindowFlags_NoTitleBar) && !(window->Flags & ImGuiWindowFlags_MenuBar))
-            rounding_corners &= ~ImDrawFlags_NoRoundCornerTR;
+            rounding_corners |= ImDrawFlags_RoundCornersTopRight;
         if (!window->ScrollbarX)
-            rounding_corners &= ~ImDrawFlags_NoRoundCornerBR;
+            rounding_corners |= ImDrawFlags_RoundCornersBottomRight;
     }
     float size_avail = window->InnerRect.Max[axis] - window->InnerRect.Min[axis];
     float size_contents = window->ContentSize[axis] + window->WindowPadding[axis] * 2.0f;
@@ -1586,12 +1586,12 @@ bool ImGui::BeginCombo(const char* label, const char* preview_value, ImGuiComboF
     const float value_x2 = ImMax(frame_bb.Min.x, frame_bb.Max.x - arrow_size);
     RenderNavHighlight(frame_bb, id);
     if (!(flags & ImGuiComboFlags_NoPreview))
-        window->DrawList->AddRectFilled(frame_bb.Min, ImVec2(value_x2, frame_bb.Max.y), frame_col, style.FrameRounding, (flags & ImGuiComboFlags_NoArrowButton) ? 0 : ImDrawFlags_NoRoundCornerR);
+        window->DrawList->AddRectFilled(frame_bb.Min, ImVec2(value_x2, frame_bb.Max.y), frame_col, style.FrameRounding, (flags & ImGuiComboFlags_NoArrowButton) ? ImDrawFlags_RoundCornersAll : ImDrawFlags_RoundCornersLeft);
     if (!(flags & ImGuiComboFlags_NoArrowButton))
     {
         ImU32 bg_col = GetColorU32((popup_open || hovered) ? ImGuiCol_ButtonHovered : ImGuiCol_Button);
         ImU32 text_col = GetColorU32(ImGuiCol_Text);
-        window->DrawList->AddRectFilled(ImVec2(value_x2, frame_bb.Min.y), frame_bb.Max, bg_col, style.FrameRounding, (w <= arrow_size) ? 0 : ImDrawFlags_NoRoundCornerL);
+        window->DrawList->AddRectFilled(ImVec2(value_x2, frame_bb.Min.y), frame_bb.Max, bg_col, style.FrameRounding, (w <= arrow_size) ? ImDrawFlags_RoundCornersAll : ImDrawFlags_RoundCornersRight);
         if (value_x2 + arrow_size - style.FramePadding.x <= frame_bb.Max.x)
             RenderArrow(window->DrawList, ImVec2(value_x2 + style.FramePadding.y, frame_bb.Min.y + style.FramePadding.y), text_col, ImGuiDir_Down, 1.0f);
     }
@@ -5367,8 +5367,8 @@ bool ImGui::ColorButton(const char* desc_id, const ImVec4& col, ImGuiColorEditFl
     if ((flags & ImGuiColorEditFlags_AlphaPreviewHalf) && col_rgb.w < 1.0f)
     {
         float mid_x = IM_ROUND((bb_inner.Min.x + bb_inner.Max.x) * 0.5f);
-        RenderColorRectWithAlphaCheckerboard(window->DrawList, ImVec2(bb_inner.Min.x + grid_step, bb_inner.Min.y), bb_inner.Max, GetColorU32(col_rgb), grid_step, ImVec2(-grid_step + off, off), rounding, ImDrawFlags_NoRoundCornerL);
-        window->DrawList->AddRectFilled(bb_inner.Min, ImVec2(mid_x, bb_inner.Max.y), GetColorU32(col_rgb_without_alpha), rounding, ImDrawFlags_NoRoundCornerR);
+        RenderColorRectWithAlphaCheckerboard(window->DrawList, ImVec2(bb_inner.Min.x + grid_step, bb_inner.Min.y), bb_inner.Max, GetColorU32(col_rgb), grid_step, ImVec2(-grid_step + off, off), rounding, ImDrawFlags_RoundCornersRight);
+        window->DrawList->AddRectFilled(bb_inner.Min, ImVec2(mid_x, bb_inner.Max.y), GetColorU32(col_rgb_without_alpha), rounding, ImDrawFlags_RoundCornersLeft);
     }
     else
     {