Internals: SliderBehaviorT: Minor refactor, clearer 0.0/1.0 early out. Should be no-op from user's point of view.

ScaleValueFromRatioT() had early 0.0/1.0 ratio tests, shifting most of function by one indent.

imgui_widgets.cpp

@@ -2615,7 +2615,6 @@ float ImGui::ScaleRatioFromValueT(ImGuiDataType data_type, TYPE v, TYPE v_min, T
             v_max_fudged = -logarithmic_zero_epsilon;
 
         float result;
-
         if (v_clamped <= v_min_fudged)
             result = 0.0f; // Workaround for values that are in-range but below our fudge
         else if (v_clamped >= v_max_fudged)
@@ -2639,35 +2638,32 @@ float ImGui::ScaleRatioFromValueT(ImGuiDataType data_type, TYPE v, TYPE v_min, T
 
         return flipped ? (1.0f - result) : result;
     }
-
+    else
+    {
         // Linear slider
         return (float)((FLOATTYPE)(SIGNEDTYPE)(v_clamped - v_min) / (FLOATTYPE)(SIGNEDTYPE)(v_max - v_min));
     }
+}
 
 // Convert a parametric position on a slider into a value v in the output space (the logical opposite of ScaleRatioFromValueT)
 template<typename TYPE, typename SIGNEDTYPE, typename FLOATTYPE>
 TYPE ImGui::ScaleValueFromRatioT(ImGuiDataType data_type, float t, TYPE v_min, TYPE v_max, bool is_logarithmic, float logarithmic_zero_epsilon, float zero_deadzone_halfsize)
 {
-    if (v_min == v_max)
+    // We special-case the extents because otherwise our logarithmic fudging can lead to "mathematically correct"
+    // but non-intuitive behaviors like a fully-left slider not actually reaching the minimum value. Also generally simpler.
+    if (t <= 0.0f || v_min == v_max)
         return v_min;
-    const bool is_floating_point = (data_type == ImGuiDataType_Float) || (data_type == ImGuiDataType_Double);
+    if (t >= 1.0f)
+        return v_max;
 
-    TYPE result;
+    TYPE result = (TYPE)0;
     if (is_logarithmic)
     {
-        // We special-case the extents because otherwise our fudging can lead to "mathematically correct" but non-intuitive behaviors like a fully-left slider not actually reaching the minimum value
-        if (t <= 0.0f)
-            result = v_min;
-        else if (t >= 1.0f)
-            result = v_max;
-        else
-        {
-            bool flipped = v_max < v_min; // Check if range is "backwards"
-
         // Fudge min/max to avoid getting silly results close to zero
         FLOATTYPE v_min_fudged = (ImAbs((FLOATTYPE)v_min) < logarithmic_zero_epsilon) ? ((v_min < 0.0f) ? -logarithmic_zero_epsilon : logarithmic_zero_epsilon) : (FLOATTYPE)v_min;
         FLOATTYPE v_max_fudged = (ImAbs((FLOATTYPE)v_max) < logarithmic_zero_epsilon) ? ((v_max < 0.0f) ? -logarithmic_zero_epsilon : logarithmic_zero_epsilon) : (FLOATTYPE)v_max;
 
+        const bool flipped = v_max < v_min; // Check if range is "backwards"
         if (flipped)
             ImSwap(v_min_fudged, v_max_fudged);
 
@@ -2694,36 +2690,29 @@ TYPE ImGui::ScaleValueFromRatioT(ImGuiDataType data_type, float t, TYPE v_min, T
         else
             result = (TYPE)(v_min_fudged * ImPow(v_max_fudged / v_min_fudged, (FLOATTYPE)t_with_flip));
     }
-    }
     else
     {
         // Linear slider
+        const bool is_floating_point = (data_type == ImGuiDataType_Float) || (data_type == ImGuiDataType_Double);
         if (is_floating_point)
         {
             result = ImLerp(v_min, v_max, t);
         }
-        else
+        else if (t < 1.0)
         {
             // - For integer values we want the clicking position to match the grab box so we round above
             //   This code is carefully tuned to work with large values (e.g. high ranges of U64) while preserving this property..
             // - Not doing a *1.0 multiply at the end of a range as it tends to be lossy. While absolute aiming at a large s64/u64
             //   range is going to be imprecise anyway, with this check we at least make the edge values matches expected limits.
-            if (t < 1.0)
-            {
             FLOATTYPE v_new_off_f = (SIGNEDTYPE)(v_max - v_min) * t;
             result = (TYPE)((SIGNEDTYPE)v_min + (SIGNEDTYPE)(v_new_off_f + (FLOATTYPE)(v_min > v_max ? -0.5 : 0.5)));
         }
-            else
-            {
-                result = v_max;
-            }
-        }
     }
 
     return result;
 }
 
-// FIXME: Move more of the code into SliderBehavior()
+// FIXME: Try to move more of the code into shared SliderBehavior()
 template<typename TYPE, typename SIGNEDTYPE, typename FLOATTYPE>
 bool ImGui::SliderBehaviorT(const ImRect& bb, ImGuiID id, ImGuiDataType data_type, TYPE* v, const TYPE v_min, const TYPE v_max, const char* format, ImGuiSliderFlags flags, ImRect* out_grab_bb)
 {
@@ -2733,11 +2722,12 @@ bool ImGui::SliderBehaviorT(const ImRect& bb, ImGuiID id, ImGuiDataType data_typ
     const ImGuiAxis axis = (flags & ImGuiSliderFlags_Vertical) ? ImGuiAxis_Y : ImGuiAxis_X;
     const bool is_logarithmic = (flags & ImGuiSliderFlags_Logarithmic) != 0;
     const bool is_floating_point = (data_type == ImGuiDataType_Float) || (data_type == ImGuiDataType_Double);
+    const SIGNEDTYPE v_range = (v_min < v_max ? v_max - v_min : v_min - v_max);
 
-    const float grab_padding = 2.0f;
+    // Calculate bounds
+    const float grab_padding = 2.0f; // FIXME: Should be part of style.
     const float slider_sz = (bb.Max[axis] - bb.Min[axis]) - grab_padding * 2.0f;
     float grab_sz = style.GrabMinSize;
-    SIGNEDTYPE v_range = (v_min < v_max ? v_max - v_min : v_min - v_max);
     if (!is_floating_point && v_range >= 0)                                     // v_range < 0 may happen on integer overflows
         grab_sz = ImMax((float)(slider_sz / (v_range + 1)), style.GrabMinSize); // For integer sliders: if possible have the grab size represent 1 unit
     grab_sz = ImMin(grab_sz, slider_sz);
@@ -2770,7 +2760,8 @@ bool ImGui::SliderBehaviorT(const ImRect& bb, ImGuiID id, ImGuiDataType data_typ
             else
             {
                 const float mouse_abs_pos = g.IO.MousePos[axis];
-                clicked_t = (slider_usable_sz > 0.0f) ? ImClamp((mouse_abs_pos - slider_usable_pos_min) / slider_usable_sz, 0.0f, 1.0f) : 0.0f;
+                if (slider_usable_sz > 0.0f)
+                    clicked_t = ImSaturate((mouse_abs_pos - slider_usable_pos_min) / slider_usable_sz);
                 if (axis == ImGuiAxis_Y)
                     clicked_t = 1.0f - clicked_t;
                 set_new_value = true;