Density tooltip for whole slider

+ allowe value out of slider range
+ add minimal value
+ slider starts at 50%

src/libslic3r/SLA/SupportIslands/SampleConfigFactory.cpp

@@ -97,3 +97,24 @@ SampleConfig &SampleConfigFactory::get_sample_config() {
         gui_sample_config_opt = sla::SampleConfigFactory::create(.4f); 
     return *gui_sample_config_opt;
 }
+
+SampleConfig SampleConfigFactory::get_sample_config(float density) {
+    const SampleConfig &current = get_sample_config();
+    if (is_approx(density, 1.f))
+        return current;
+    if (density < .1f)
+        density = .1f; // minimal 10%
+
+    SampleConfig result = current; // copy
+    result.thin_max_distance = static_cast<coord_t>(current.thin_max_distance / density); // linear
+    result.thick_inner_max_distance = static_cast<coord_t>( // controll radius - quadratic
+        std::sqrt(sqr((double)current.thick_inner_max_distance) / density));
+    result.thick_outline_max_distance = static_cast<coord_t>(current.thick_outline_max_distance / density); // linear
+    // result.head_radius                       .. no change
+    // result.minimal_distance_from_outline     .. no change
+    // result.maximal_distance_from_outline     .. no change
+    // result.max_length_for_one_support_point  .. no change
+    // result.max_length_for_two_support_points .. no change
+    verify(result);
+    return result;
+}

src/libslic3r/SLA/SupportIslands/SampleConfigFactory.hpp

@@ -24,6 +24,16 @@ private:
     static std::optional<SampleConfig> gui_sample_config_opt;
 public:
     static SampleConfig &get_sample_config();
+
+    /// <summary>
+    /// Create scaled copy of sample config
+    /// </summary>
+    /// <param name="density"> Scale for config values(minimal value is .1f)
+    /// 1.f .. no scale
+    /// .9f .. less support points (approx 90%)
+    /// 1.1f.. extend count of supports (approx to 110%) </param>
+    /// <returns>Scaled configuration</returns>
+    static SampleConfig get_sample_config(float density);
 };
 } // namespace Slic3r::sla
 #endif // slic3r_SLA_SuppotstIslands_SampleConfigFactory_hpp_

src/libslic3r/SLAPrintSteps.cpp

@@ -680,7 +680,7 @@ void SLAPrint::Steps::support_points(SLAPrintObject &po)
     }
     
     // copy current configuration for sampling islands
-    config.island_configuration = SampleConfigFactory::get_sample_config(); // copy
+    config.island_configuration = SampleConfigFactory::get_sample_config(config.density_relative);
     
     // scaling for the sub operations
     double d = objectstep_scale * OBJ_STEP_LEVELS[slaposSupportPoints] / 100.0;

src/slic3r/GUI/Gizmos/GLGizmoSlaSupports.cpp

@@ -743,10 +743,9 @@ RENDER_AGAIN:
 
         const char *support_points_density = "support_points_density_relative";
         float density = static_cast<const ConfigOptionInt*>(get_config_options({support_points_density})[0])->value; 
-        if (m_imgui->slider_float("##density", &density, 0.f, 200.f, "%.f %%")){
+
-            mo->config.set(support_points_density, (int) density);
+        wxString tooltip = _L(
-        } else if (ImGui::IsItemHovered())
+            "Divider for the supported radius\n"
-            ImGui::SetTooltip("Divider for the supported radius\n"
             "Smaller value means less point, supported radius is enlarged.\n"
             "Larger value means more points, supported radius is reduced.\n"
             "-- density percent ----- radisu change from 100 --\n"
@@ -755,6 +754,11 @@ RENDER_AGAIN:
             "|        125         |              80           |\n"
             "|        150         |              66           |\n"
             "|        200         |              50           |\n");
+        if (m_imgui->slider_float("##density", &density, 50.f, 200.f, "%.f %%", 1.f, false, tooltip)){
+            if (density < 10.f) // not neccessary, but lower value seems pointless. Zero cause issues inside algorithms.
+                density = 10.f;
+            mo->config.set(support_points_density, (int) density);
+        }
         
         const ImGuiWrapper::LastSliderStatus &density_status = m_imgui->get_last_slider_status();
         static std::optional<int> density_stash; // Value for undo/redo stack is written on stop dragging