DragInt, DragFloat, DragScalar: Using (v_min > v_max) allows locking any edit to the value.

docs/CHANGELOG.txt

@@ -44,6 +44,7 @@ Other Changes:
 - TabBar: improved shrinking for large number of tabs to avoid leaving extraneous space on the right side.
   Individuals tabs are given integer-rounded width and remainder is spread between tabs left-to-right.
 - SliderScalar: Improved assert when using U32 or U64 types with a large v_max value. (#2765) [@loicmouton]
+- DragInt, DragFloat, DragScalar: Using (v_min > v_max) allows locking any edit to the value.
 - ImDrawList: clarified the name of many parameters so reading the code is a little easier. (#2740)
 - Using offsetof() when available in C++11. Avoids Clang sanitizer complaining about old-style macros. (#94)
 - Added a mechanism to compact/free the larger allocations of unused windows (buffers are compacted when

imgui.h

@@ -426,6 +426,8 @@ namespace ImGui
     // - For all the Float2/Float3/Float4/Int2/Int3/Int4 versions of every functions, note that a 'float v[X]' function argument is the same as 'float* v', the array syntax is just a way to document the number of elements that are expected to be accessible. You can pass address of your first element out of a contiguous set, e.g. &myvector.x
     // - Adjust format string to decorate the value with a prefix, a suffix, or adapt the editing and display precision e.g. "%.3f" -> 1.234; "%5.2f secs" -> 01.23 secs; "Biscuit: %.0f" -> Biscuit: 1; etc.
     // - Speed are per-pixel of mouse movement (v_speed=0.2f: mouse needs to move by 5 pixels to increase value by 1). For gamepad/keyboard navigation, minimum speed is Max(v_speed, minimum_step_at_given_precision).
+    // - Use v_min < v_max to clamp edits to given limits. Note that CTRL+Click manual input can override those limits.
+    // - Use v_min > v_max to lock edits.
     IMGUI_API bool          DragFloat(const char* label, float* v, float v_speed = 1.0f, float v_min = 0.0f, float v_max = 0.0f, const char* format = "%.3f", float power = 1.0f);     // If v_min >= v_max we have no bound
     IMGUI_API bool          DragFloat2(const char* label, float v[2], float v_speed = 1.0f, float v_min = 0.0f, float v_max = 0.0f, const char* format = "%.3f", float power = 1.0f);
     IMGUI_API bool          DragFloat3(const char* label, float v[3], float v_speed = 1.0f, float v_min = 0.0f, float v_max = 0.0f, const char* format = "%.3f", float power = 1.0f);

imgui_widgets.cpp

@@ -1916,11 +1916,14 @@ bool ImGui::DragBehaviorT(ImGuiDataType data_type, TYPE* v, float v_speed, const
     ImGuiContext& g = *GImGui;
     const ImGuiAxis axis = (flags & ImGuiDragFlags_Vertical) ? ImGuiAxis_Y : ImGuiAxis_X;
     const bool is_decimal = (data_type == ImGuiDataType_Float) || (data_type == ImGuiDataType_Double);
-    const bool has_min_max = (v_min != v_max);
+    const bool is_clamped = (v_min < v_max);
-    const bool is_power = (power != 1.0f && is_decimal && has_min_max && (v_max - v_min < FLT_MAX));
+    const bool is_power = (power != 1.0f && is_decimal && is_clamped && (v_max - v_min < FLT_MAX));
+    const bool is_locked = (v_min > v_max);
+    if (is_locked)
+        return false;
 
     // Default tweak speed
-    if (v_speed == 0.0f && has_min_max && (v_max - v_min < FLT_MAX))
+    if (v_speed == 0.0f && is_clamped && (v_max - v_min < FLT_MAX))
         v_speed = (float)((v_max - v_min) * g.DragSpeedDefaultRatio);
 
     // Inputs accumulates into g.DragCurrentAccum, which is flushed into the current value as soon as it makes a difference with our precision settings
@@ -1948,7 +1951,7 @@ bool ImGui::DragBehaviorT(ImGuiDataType data_type, TYPE* v, float v_speed, const
     // Clear current value on activation
     // Avoid altering values and clamping when we are _already_ past the limits and heading in the same direction, so e.g. if range is 0..255, current value is 300 and we are pushing to the right side, keep the 300.
     bool is_just_activated = g.ActiveIdIsJustActivated;
-    bool is_already_past_limits_and_pushing_outward = has_min_max && ((*v >= v_max && adjust_delta > 0.0f) || (*v <= v_min && adjust_delta < 0.0f));
+    bool is_already_past_limits_and_pushing_outward = is_clamped && ((*v >= v_max && adjust_delta > 0.0f) || (*v <= v_min && adjust_delta < 0.0f));
     bool is_drag_direction_change_with_power = is_power && ((adjust_delta < 0 && g.DragCurrentAccum > 0) || (adjust_delta > 0 && g.DragCurrentAccum < 0));
     if (is_just_activated || is_already_past_limits_and_pushing_outward || is_drag_direction_change_with_power)
     {
@@ -2000,7 +2003,7 @@ bool ImGui::DragBehaviorT(ImGuiDataType data_type, TYPE* v, float v_speed, const
         v_cur = (TYPE)0;
 
     // Clamp values (+ handle overflow/wrap-around for integer types)
-    if (*v != v_cur && has_min_max)
+    if (*v != v_cur && is_clamped)
     {
         if (v_cur < v_min || (v_cur > *v && adjust_delta < 0.0f && !is_decimal))
             v_cur = v_min;