GUI: fix scrolling when stepping rows

src/engine/engine.cpp

@@ -2598,6 +2598,8 @@ void DivEngine::stepOne(int row) {
   }
   stepPlay=2;
   ticks=1;
+  prevOrder=curOrder;
+  prevRow=curRow;
   BUSY_END;
 }
 

src/engine/playback.cpp

@@ -1130,8 +1130,10 @@ void DivEngine::nextRow() {
     }
   }
 
-  prevOrder=curOrder;
+  if (!stepPlay) {
-  prevRow=curRow;
+    prevOrder=curOrder;
+    prevRow=curRow;
+  }
 
   for (int i=0; i<chans; i++) {
     if (song.delayBehavior!=2) {
@@ -1337,7 +1339,11 @@ bool DivEngine::nextTick(bool noAccum, bool inhibitLowLat) {
               }
             }
             endOfSong=false;
-            if (stepPlay==2) stepPlay=1;
+            if (stepPlay==2) {
+              stepPlay=1;
+              prevOrder=curOrder;
+              prevRow=curRow;
+            }
             nextRow();
             break;
           }

src/gui/doAction.cpp

@@ -111,6 +111,7 @@ void FurnaceGUI::doAction(int what) {
       break;
     case GUI_ACTION_STEP_ONE:
       e->stepOne(cursor.y);
+      pendingStepUpdate=1;
       break;
     case GUI_ACTION_OCTAVE_UP:
       if (++curOctave>7) {

src/gui/editControls.cpp

@@ -374,7 +374,7 @@ void FurnaceGUI::drawMobileControls() {
     if (portrait) ImGui::SameLine();
     if (ImGui::Button(ICON_FA_ARROW_DOWN "##StepOne",buttonSize)) {
       e->stepOne(cursor.y);
-      pendingStepUpdate=true;
+      pendingStepUpdate=1;
     }
 
     bool repeatPattern=e->getRepeatPattern();
@@ -730,7 +730,7 @@ void FurnaceGUI::drawEditControls() {
         ImGui::SameLine();
         if (ImGui::Button(ICON_FA_ARROW_DOWN "##StepOne")) {
           e->stepOne(cursor.y);
-          pendingStepUpdate=true;
+          pendingStepUpdate=1;
         }
         if (ImGui::IsItemHovered()) {
           ImGui::SetTooltip("Step one row");
@@ -770,7 +770,7 @@ void FurnaceGUI::drawEditControls() {
         ImGui::SameLine();
         if (ImGui::Button(ICON_FA_ARROW_DOWN "##StepOne")) {
           e->stepOne(cursor.y);
-          pendingStepUpdate=true;
+          pendingStepUpdate=1;
         }
         if (ImGui::IsItemHovered()) {
           ImGui::SetTooltip("Step one row");
@@ -875,7 +875,7 @@ void FurnaceGUI::drawEditControls() {
         }
         if (ImGui::Button(ICON_FA_ARROW_DOWN "##StepOne",buttonSize)) {
           e->stepOne(cursor.y);
-          pendingStepUpdate=true;
+          pendingStepUpdate=1;
         }
         if (ImGui::IsItemHovered()) {
           ImGui::SetTooltip("Step one row");
@@ -1009,7 +1009,7 @@ void FurnaceGUI::drawEditControls() {
         ImGui::SameLine();
         if (ImGui::Button(ICON_FA_ARROW_DOWN "##StepOne")) {
           e->stepOne(cursor.y);
-          pendingStepUpdate=true;
+          pendingStepUpdate=1;
         }
         if (ImGui::IsItemHovered()) {
           ImGui::SetTooltip("Step one row");

src/gui/gui.cpp

@@ -7015,7 +7015,7 @@ FurnaceGUI::FurnaceGUI():
   fadeMode(false),
   randomMode(false),
   haveHitBounds(false),
-  pendingStepUpdate(false),
+  pendingStepUpdate(0),
   oldOrdersLen(0),
   sampleZoom(1.0),
   prevSampleZoom(1.0),

src/gui/gui.h

@@ -1913,7 +1913,8 @@ class FurnaceGUI {
   int dummyRows, demandX;
   int transposeAmount, randomizeMin, randomizeMax, fadeMin, fadeMax, collapseAmount;
   float scaleMax;
-  bool fadeMode, randomMode, haveHitBounds, pendingStepUpdate;
+  bool fadeMode, randomMode, haveHitBounds;
+  signed char pendingStepUpdate;
 
   int oldOrdersLen;
   DivOrders oldOrders;

src/gui/pattern.cpp

@@ -446,7 +446,7 @@ void FurnaceGUI::drawPattern() {
       float lineHeight=(ImGui::GetTextLineHeight()+2*dpiScale);
       int curRow=e->getRow();
       if (e->isPlaying() && followPattern && (!e->isStepping() || pendingStepUpdate)) updateScroll(curRow);
-      pendingStepUpdate=false;
+      if (--pendingStepUpdate<0) pendingStepUpdate=0;
       if (nextScroll>-0.5f) {
         ImGui::SetScrollY(nextScroll);
         nextScroll=-1.0f;