Drags, Sliders: Added ImGuiDragFlags_NoRoundToFormat / ImGuiSliderFlags_NoRoundToFormat flags (#642)

docs/CHANGELOG.txt

@@ -76,6 +76,8 @@ Other Changes:
   'float power' parameter which was obsoleted. (#1823, #1316, #642) [@Shironekoben, @AndrewBelt]
 - Drag, Slider: Added ImGuiDragFlags_ClampOnInput/ImGuiSliderFlags_ClampOnInput flags to force
   clamping value when using CTRL+Click to type in a value manually. (#1829, #3209, #946, #413).
+- Drag, Slider: Added ImGuiDragFlags_NoRoundToFormat/ImGuiSliderFlags_NoRoundToFormat flags
+  to disable rounding underlying value to match precision of the display format string. (#642)
 - DragFloatRange2, DragIntRange2: Fixed an issue allowing to drag out of bounds when both
   min and max value are on the same value. (#1441)
 - InputText, ImDrawList: Fixed assert triggering when drawing single line of text with more

imgui.h

@@ -1296,7 +1296,8 @@ enum ImGuiDragFlags_
     ImGuiDragFlags_None                     = 0,
     ImGuiDragFlags_InvalidMask_             = 0x7000000F,   // [Internal] We treat using those bits as being potentially a 'float power' argument from the previous API that has got miscast to this enum, and will trigger an assert if needed.
     ImGuiDragFlags_ClampOnInput             = 1 << 4,       // Clamp value to min/max bounds (if any) when input manually with CTRL+Click. By default CTRL+Click allows going out of bounds.
-    ImGuiDragFlags_Logarithmic              = 1 << 5        // Should this widget be logarithmic? (linear otherwise)
+    ImGuiDragFlags_Logarithmic              = 1 << 5,       // Make the widget logarithmic (linear otherwise)
+    ImGuiDragFlags_NoRoundToFormat          = 1 << 6        // Disable rounding underlying value to match precision of the display format string (e.g. %.3f values are rounded to those 3 digits)
 };
 
 // Flags for SliderFloat(), SliderInt() etc.
@@ -1305,7 +1306,8 @@ enum ImGuiSliderFlags_
     ImGuiSliderFlags_None                   = 0,
     ImGuiSliderFlags_InvalidMask_           = 0x7000000F,   // [Internal] We treat using those bits as being potentially a 'float power' argument from the previous API that has got miscast to this enum, and will trigger an assert if needed.
     ImGuiSliderFlags_ClampOnInput           = 1 << 4,       // Clamp value to min/max bounds when input manually with CTRL+Click. By default CTRL+Click allows going out of bounds.
-    ImGuiSliderFlags_Logarithmic            = 1 << 5        // Should this widget be logarithmic? (linear otherwise)
+    ImGuiSliderFlags_Logarithmic            = 1 << 5,       // Make the widget logarithmic (linear otherwise)
+    ImGuiSliderFlags_NoRoundToFormat        = 1 << 6        // Disable rounding underlying value to match precision of the display format string (e.g. %.3f values are rounded to those 3 digits)
 };
 
 // Identify a mouse button.

imgui_demo.cpp

@@ -1496,13 +1496,16 @@ static void ShowDemoWindowWidgets()
         ImGui::SameLine(); HelpMarker("Always clamp value to min/max bounds (if any) when input manually with CTRL+Click.");
         ImGui::CheckboxFlags("ImGuiDragFlags_Logarithmic", (unsigned int*)&drag_flags, ImGuiDragFlags_Logarithmic);
         ImGui::SameLine(); HelpMarker("Enable logarithmic editing (more precision for small values).");
+        ImGui::CheckboxFlags("ImGuiDragFlags_NoRoundToFormat", (unsigned int*)&drag_flags, ImGuiDragFlags_NoRoundToFormat);
+        ImGui::SameLine(); HelpMarker("Disable rounding underlying value to match precision of the format string (e.g. %.3f values are rounded to those 3 digits).");
 
         static float drag_f = 0.5f;
         static int drag_i = 50;
-        ImGui::DragFloat("DragFloat (0 -> 1)", &drag_f, 0.005f, 0.0f, 1.0f, "%f", drag_flags);
-        ImGui::DragFloat("DragFloat (0 -> +inf)", &drag_f, 0.005f, 0.0f, FLT_MAX, "%f", drag_flags);
-        ImGui::DragFloat("DragFloat (-inf -> 1)", &drag_f, 0.005f, -FLT_MAX, 1.0f, "%f", drag_flags);
-        ImGui::DragFloat("DragFloat (-inf -> +inf)", &drag_f, 0.005f, -FLT_MAX, +FLT_MAX, "%f", drag_flags);
+        ImGui::Text("Underlying float value: %f", drag_f);
+        ImGui::DragFloat("DragFloat (0 -> 1)", &drag_f, 0.005f, 0.0f, 1.0f, "%.3f", drag_flags);
+        ImGui::DragFloat("DragFloat (0 -> +inf)", &drag_f, 0.005f, 0.0f, FLT_MAX, "%.3f", drag_flags);
+        ImGui::DragFloat("DragFloat (-inf -> 1)", &drag_f, 0.005f, -FLT_MAX, 1.0f, "%.3f", drag_flags);
+        ImGui::DragFloat("DragFloat (-inf -> +inf)", &drag_f, 0.005f, -FLT_MAX, +FLT_MAX, "%.3f", drag_flags);
         ImGui::DragInt("DragInt (0 -> 100)", &drag_i, 0.5f, 0, 100, "%d", drag_flags);
 
         // Demonstrate using advanced flags for SliderXXX functions
@@ -1511,11 +1514,14 @@ static void ShowDemoWindowWidgets()
         ImGui::SameLine(); HelpMarker("Always clamp value to min/max bounds (if any) when input manually with CTRL+Click.");
         ImGui::CheckboxFlags("ImGuiSliderFlags_Logarithmic", (unsigned int*)&slider_flags, ImGuiSliderFlags_Logarithmic);
         ImGui::SameLine(); HelpMarker("Enable logarithmic editing (more precision for small values).");
+        ImGui::CheckboxFlags("ImGuiSliderFlags_NoRoundToFormat", (unsigned int*)&slider_flags, ImGuiSliderFlags_NoRoundToFormat);
+        ImGui::SameLine(); HelpMarker("Disable rounding underlying value to match precision of the format string (e.g. %.3f values are rounded to those 3 digits).");
 
         static float slider_f = 0.5f;
         static int slider_i = 50;
-        ImGui::SliderFloat("SliderFloat (0 -> 1)", &slider_f, 0.0f, 1.0f, NULL, slider_flags);
-        ImGui::SliderInt("SliderInt (0 -> 100)", &slider_i, 0, 100, NULL, slider_flags);
+        ImGui::Text("Underlying float value: %f", slider_f);
+        ImGui::SliderFloat("SliderFloat (0 -> 1)", &slider_f, 0.0f, 1.0f, "%.3f", slider_flags);
+        ImGui::SliderInt("SliderInt (0 -> 100)", &slider_i, 0, 100, "%.3f", slider_flags);
 
         ImGui::TreePop();
     }

imgui_widgets.cpp

@@ -2079,7 +2079,8 @@ bool ImGui::DragBehaviorT(ImGuiDataType data_type, TYPE* v, float v_speed, const
     }
 
     // Round to user desired precision based on format string
-    v_cur = RoundScalarWithFormatT<TYPE, SIGNEDTYPE>(format, data_type, v_cur);
+    if (!(flags & ImGuiDragFlags_NoRoundToFormat))
+        v_cur = RoundScalarWithFormatT<TYPE, SIGNEDTYPE>(format, data_type, v_cur);
 
     // Preserve remainder after rounding has been applied. This also allow slow tweaking of values.
     g.DragCurrentAccumDirty = false;
@@ -2636,7 +2637,8 @@ bool ImGui::SliderBehaviorT(const ImRect& bb, ImGuiID id, ImGuiDataType data_typ
             TYPE v_new = SliderCalcValueFromRatioT<TYPE, FLOATTYPE>(data_type, clicked_t, v_min, v_max, logarithmic_zero_epsilon, flags);
 
             // Round to user desired precision based on format string
-            v_new = RoundScalarWithFormatT<TYPE, SIGNEDTYPE>(format, data_type, v_new);
+            if (!(flags & ImGuiSliderFlags_NoRoundToFormat))
+                v_new = RoundScalarWithFormatT<TYPE, SIGNEDTYPE>(format, data_type, v_new);
 
             // Apply result
             if (*v != v_new)