InputInt, InputScalar: +/- buttons now respects the natural type limits instead of overflowing or underflowing the value.

docs/CHANGELOG.txt

@@ -47,6 +47,8 @@ Other Changes:
 - InputInt, InputFloat, InputScalar: Fix to keep the label of the +/- buttons centered when
   style.FramePadding.x is abnormally larger than style.FramePadding.y. Since the buttons are
   meant to be square (to align with e.g. color button) we always use FramePadding.y. (#2367)
+- InputInt, InputScalar: +/- buttons now respects the natural type limits instead of
+  overflowing or underflowing the value.
 - InputText: Fixed an edge case crash that would happen if another widget sharing the same ID
   is being swapped with an InputText that has yet to be activated.
 - InputText: Fixed various display corruption related to swapping the underlying buffer while

imgui_internal.h

@@ -225,12 +225,15 @@ static inline double ImAtof(const char* s)
 static inline float  ImFloorStd(float x)                                        { return floorf(x); }   // we already uses our own ImFloor() { return (float)(int)v } internally so the standard one wrapper is named differently (it's used by stb_truetype)
 static inline float  ImCeil(float x)                                            { return ceilf(x); }
 #endif
-// - ImMin/ImMax/ImClamp/ImLerp/ImSwap are used by widgets which support for variety of types: signed/unsigned int/long long float/double, using templates here but we could also redefine them 6 times
+// - ImMin/ImMax/ImClamp/ImLerp/ImSwap are used by widgets which support for variety of types: signed/unsigned int/long long float/double
+// (Exceptionally using templates here but we could also redefine them for variety of types)
 template<typename T> static inline T ImMin(T lhs, T rhs)                        { return lhs < rhs ? lhs : rhs; }
 template<typename T> static inline T ImMax(T lhs, T rhs)                        { return lhs >= rhs ? lhs : rhs; }
 template<typename T> static inline T ImClamp(T v, T mn, T mx)                   { return (v < mn) ? mn : (v > mx) ? mx : v; }
 template<typename T> static inline T ImLerp(T a, T b, float t)                  { return (T)(a + (b - a) * t); }
 template<typename T> static inline void ImSwap(T& a, T& b)                      { T tmp = a; a = b; b = tmp; }
+template<typename T> static inline T ImAddClampOverflow(T a, T b, T mn, T mx)   { if (b < 0 && (a < mn - b)) return mn; if (b > 0 && (a > mx - b)) return mx; return a + b; }
+template<typename T> static inline T ImSubClampOverflow(T a, T b, T mn, T mx)   { if (b > 0 && (a < mn + b)) return mn; if (b < 0 && (a > mx + b)) return mx; return a - b; }
 // - Misc maths helpers
 static inline ImVec2 ImMin(const ImVec2& lhs, const ImVec2& rhs)                { return ImVec2(lhs.x < rhs.x ? lhs.x : rhs.x, lhs.y < rhs.y ? lhs.y : rhs.y); }
 static inline ImVec2 ImMax(const ImVec2& lhs, const ImVec2& rhs)                { return ImVec2(lhs.x >= rhs.x ? lhs.x : rhs.x, lhs.y >= rhs.y ? lhs.y : rhs.y); }

imgui_widgets.cpp

@@ -1568,51 +1568,50 @@ static inline int DataTypeFormatString(char* buf, int buf_size, ImGuiDataType da
     return 0;
 }
 
-// FIXME: Adding support for clamping on boundaries of the data type would be nice.
 static void DataTypeApplyOp(ImGuiDataType data_type, int op, void* output, void* arg1, const void* arg2)
 {
     IM_ASSERT(op == '+' || op == '-');
     switch (data_type)
     {
         case ImGuiDataType_S8:
-            if (op == '+')      *(ImS8*)output = *(const ImS8*)arg1 + *(const ImS8*)arg2;
-            else if (op == '-') *(ImS8*)output = *(const ImS8*)arg1 - *(const ImS8*)arg2;
+            if (op == '+') { *(ImS8*)output  = ImAddClampOverflow(*(const ImS8*)arg1,  *(const ImS8*)arg2,  IM_S8_MIN,  IM_S8_MAX); }
+            if (op == '-') { *(ImS8*)output  = ImSubClampOverflow(*(const ImS8*)arg1,  *(const ImS8*)arg2,  IM_S8_MIN,  IM_S8_MAX); }
             return;
         case ImGuiDataType_U8:
-            if (op == '+')      *(ImU8*)output = *(const ImU8*)arg1 + *(const ImU8*)arg2;
-            else if (op == '-') *(ImU8*)output = *(const ImU8*)arg1 - *(const ImU8*)arg2;
+            if (op == '+') { *(ImU8*)output  = ImAddClampOverflow(*(const ImU8*)arg1,  *(const ImU8*)arg2,  IM_U8_MIN,  IM_U8_MAX); }
+            if (op == '-') { *(ImU8*)output  = ImSubClampOverflow(*(const ImU8*)arg1,  *(const ImU8*)arg2,  IM_U8_MIN,  IM_U8_MAX); }
             return;
         case ImGuiDataType_S16:
-            if (op == '+')      *(ImS16*)output = *(const ImS16*)arg1 + *(const ImS16*)arg2;
-            else if (op == '-') *(ImS16*)output = *(const ImS16*)arg1 - *(const ImS16*)arg2;
+            if (op == '+') { *(ImS16*)output = ImAddClampOverflow(*(const ImS16*)arg1, *(const ImS16*)arg2, IM_S16_MIN, IM_S16_MAX); }
+            if (op == '-') { *(ImS16*)output = ImSubClampOverflow(*(const ImS16*)arg1, *(const ImS16*)arg2, IM_S16_MIN, IM_S16_MAX); }
             return;
         case ImGuiDataType_U16:
-            if (op == '+')      *(ImU16*)output = *(const ImU16*)arg1 + *(const ImU16*)arg2;
-            else if (op == '-') *(ImU16*)output = *(const ImU16*)arg1 - *(const ImU16*)arg2;
+            if (op == '+') { *(ImU16*)output = ImAddClampOverflow(*(const ImU16*)arg1, *(const ImU16*)arg2, IM_U16_MIN, IM_U16_MAX); }
+            if (op == '-') { *(ImU16*)output = ImSubClampOverflow(*(const ImU16*)arg1, *(const ImU16*)arg2, IM_U16_MIN, IM_U16_MAX); }
             return;
         case ImGuiDataType_S32:
-            if (op == '+')      *(ImS32*)output = *(const ImS32*)arg1 + *(const ImS32*)arg2;
-            else if (op == '-') *(ImS32*)output = *(const ImS32*)arg1 - *(const ImS32*)arg2;
+            if (op == '+') { *(ImS32*)output = ImAddClampOverflow(*(const ImS32*)arg1, *(const ImS32*)arg2, IM_S32_MIN, IM_S32_MAX); }
+            if (op == '-') { *(ImS32*)output = ImSubClampOverflow(*(const ImS32*)arg1, *(const ImS32*)arg2, IM_S32_MIN, IM_S32_MAX); }
             return;
         case ImGuiDataType_U32:
-            if (op == '+')      *(ImU32*)output = *(const ImU32*)arg1 + *(const ImU32*)arg2;
-            else if (op == '-') *(ImU32*)output = *(const ImU32*)arg1 - *(const ImU32*)arg2;
+            if (op == '+') { *(ImU32*)output = ImAddClampOverflow(*(const ImU32*)arg1, *(const ImU32*)arg2, IM_U32_MIN, IM_U32_MAX); }
+            if (op == '-') { *(ImU32*)output = ImSubClampOverflow(*(const ImU32*)arg1, *(const ImU32*)arg2, IM_U32_MIN, IM_U32_MAX); }
             return;
         case ImGuiDataType_S64:
-            if (op == '+')      *(ImS64*)output = *(const ImS64*)arg1 + *(const ImS64*)arg2;
-            else if (op == '-') *(ImS64*)output = *(const ImS64*)arg1 - *(const ImS64*)arg2;
+            if (op == '+') { *(ImS64*)output = ImAddClampOverflow(*(const ImS64*)arg1, *(const ImS64*)arg2, IM_S64_MIN, IM_S64_MAX); }
+            if (op == '-') { *(ImS64*)output = ImSubClampOverflow(*(const ImS64*)arg1, *(const ImS64*)arg2, IM_S64_MIN, IM_S64_MAX); }
             return;
         case ImGuiDataType_U64:
-            if (op == '+')      *(ImU64*)output = *(const ImU64*)arg1 + *(const ImU64*)arg2;
-            else if (op == '-') *(ImU64*)output = *(const ImU64*)arg1 - *(const ImU64*)arg2;
+            if (op == '+') { *(ImU64*)output = ImAddClampOverflow(*(const ImU64*)arg1, *(const ImU64*)arg2, IM_U64_MIN, IM_U64_MAX); }
+            if (op == '-') { *(ImU64*)output = ImSubClampOverflow(*(const ImU64*)arg1, *(const ImU64*)arg2, IM_U64_MIN, IM_U64_MAX); }
             return;
         case ImGuiDataType_Float:
-            if (op == '+')      *(float*)output = *(const float*)arg1 + *(const float*)arg2;
-            else if (op == '-') *(float*)output = *(const float*)arg1 - *(const float*)arg2;
+            if (op == '+') { *(float*)output = *(const float*)arg1 + *(const float*)arg2; }
+            if (op == '-') { *(float*)output = *(const float*)arg1 - *(const float*)arg2; }
             return;
         case ImGuiDataType_Double:
-            if (op == '+')      *(double*)output = *(const double*)arg1 + *(const double*)arg2;
-            else if (op == '-') *(double*)output = *(const double*)arg1 - *(const double*)arg2;
+            if (op == '+') { *(double*)output = *(const double*)arg1 + *(const double*)arg2; } 
+            if (op == '-') { *(double*)output = *(const double*)arg1 - *(const double*)arg2; }
             return;
         case ImGuiDataType_COUNT: break;
     }