DoubleSlider: Fixed draw of the ruler for sequential print (#7854)

+ Fixed a condition for detection of sequential print (may caused a crash from #7263)
+ suppress to show ruler ticks when step was not detected

src/slic3r/GUI/DoubleSlider.cpp

@@ -1085,6 +1085,8 @@ void Control::Ruler::update(wxWindow* win, const std::vector<double>& values, do
     }
 
     long_step = step == 0 ? -1.0 : (double)step* std::pow(10, pow);
+    if (long_step < 0)
+        short_step = long_step;
 }
 
 void Control::draw_ruler(wxDC& dc)
@@ -1103,44 +1105,76 @@ void Control::draw_ruler(wxDC& dc)
     wxColour old_clr = dc.GetTextForeground();
     dc.SetTextForeground(GREY_PEN.GetColour());
 
-    if (m_ruler.long_step < 0)
+    auto draw_short_ticks = [this, mid](wxDC& dc, double& current_tick, int max_tick) {
-        for (size_t tick = 1; tick < m_values.size(); tick++) {
+        if (m_ruler.short_step <= 0.0)
-            wxCoord pos = get_position_from_value(tick);
+            return;
-            draw_ticks_pair(dc, pos, mid, 5);
+        while (current_tick < max_tick) {
-            draw_tick_text(dc, wxPoint(mid, pos), tick);
+            wxCoord pos = get_position_from_value(lround(current_tick));
+            draw_ticks_pair(dc, pos, mid, 2);
+            current_tick += m_ruler.short_step;
+            if (current_tick > m_max_value)
+                break;
         }
-    else {
+    };
-        auto draw_short_ticks = [this, mid](wxDC& dc, double& current_tick, int max_tick) {
+
-            while (current_tick < max_tick) {
+    double short_tick = std::nan("");
-                wxCoord pos = get_position_from_value(lround(current_tick));
+    int tick = 0;
-                draw_ticks_pair(dc, pos, mid, 2);
+    double value = 0.0;
-                current_tick += m_ruler.short_step;
+    size_t sequence = 0;
-                if (current_tick > m_max_value)
+    int prev_y_pos = -1;
+    wxCoord label_height = dc.GetMultiLineTextExtent("0").y - 2;
+    int values_size = (int)m_values.size();
+
+    if (m_ruler.long_step < 0) {
+        // sequential print when long_step wasn't detected because of a lot of printed objects 
+        if (m_ruler.max_values.size() > 1) {
+            while (tick <= m_max_value && sequence < m_ruler.count()) {
+                // draw just ticks with max value
+                value = m_ruler.max_values[sequence];
+                short_tick = tick;
+
+                for (; tick < values_size; tick++) {
+                    if (m_values[tick] == value)
+                        break;
+                    if (m_values[tick] > value) {
+                        if (tick > 0)
+                            tick--;
+                        break;
+                    }
+                }
+                if (tick > m_max_value)
                     break;
+
+                wxCoord pos = get_position_from_value(tick);
+                draw_ticks_pair(dc, pos, mid, 5);
+                if (prev_y_pos < 0 || prev_y_pos - pos >= label_height) {
+                    draw_tick_text(dc, wxPoint(mid, pos), tick);
+                    prev_y_pos = pos;
+                }
+                draw_short_ticks(dc, short_tick, tick);
+
+                sequence++;
+                tick++;
             }
-        };
+        }
-
+        // very short object or some non-trivial ruler with non-regular step (see https://github.com/prusa3d/PrusaSlicer/issues/7263)
-        double short_tick = std::nan("");
+        else {
-        int tick = 0;
+            if (get_scroll_step() < 1) // step less then 1 px indicates very tall object with non-regular laayer step (probably in vase mode)
-        double value = 0.0;
+                return;
-        size_t sequence = 0;
+            for (size_t tick = 1; tick < m_values.size(); tick++) {
-
+                wxCoord pos = get_position_from_value(tick);
-        int prev_y_pos = -1;
+                draw_ticks_pair(dc, pos, mid, 5);
-        wxCoord label_height = dc.GetMultiLineTextExtent("0").y - 2;
+                draw_tick_text(dc, wxPoint(mid, pos), tick);
-        int values_size = (int)m_values.size();
+            }
-
+        }
+    }
+    else {
         while (tick <= m_max_value) {
             value += m_ruler.long_step;
-            if (value > m_ruler.max_values[sequence] && sequence < m_ruler.count()) {
+
-                value = m_ruler.long_step;
+            if (sequence < m_ruler.count() && value > m_ruler.max_values[sequence])
-                for (; tick < values_size; tick++)
+                value = m_ruler.max_values[sequence];
-                    if (m_values[tick] < value)
+
-                        break;
-                // short ticks from the last tick to the end of current sequence
-                assert(! std::isnan(short_tick));
-                draw_short_ticks(dc, short_tick, tick);
-                sequence++;
-            }
             short_tick = tick;
 
             for (; tick < values_size; tick++) {
@@ -1164,7 +1198,7 @@ void Control::draw_ruler(wxDC& dc)
 
             draw_short_ticks(dc, short_tick, tick);
 
-            if (value == m_ruler.max_values[sequence] && sequence < m_ruler.count()) {
+            if (sequence < m_ruler.count() && value == m_ruler.max_values[sequence]) {
                 value = 0.0;
                 sequence++;
                 tick++;