From 3164f311f5aec6dbddff4169894a30f9e59a0d2e Mon Sep 17 00:00:00 2001
From: tildearrow <me@tildearrow.org>
Date: Thu, 17 Oct 2024 01:52:06 -0500
Subject: [PATCH] GUI: fix visualizer when things are on

issue #2212
---
 src/gui/gui.cpp     | 1 +
 src/gui/gui.h       | 1 +
 src/gui/pattern.cpp | 8 ++++++--
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index 34343f63f..271717d70 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -8709,6 +8709,7 @@ FurnaceGUI::FurnaceGUI():
   fadeMin(0),
   fadeMax(255),
   collapseAmount(2),
+  playheadY(0.0f),
   scaleMax(100.0f),
   fadeMode(false),
   randomMode(false),
diff --git a/src/gui/gui.h b/src/gui/gui.h
index 7678cf601..66a135df9 100644
--- a/src/gui/gui.h
+++ b/src/gui/gui.h
@@ -2528,6 +2528,7 @@ class FurnaceGUI {
   SelectionPoint sel1, sel2;
   int dummyRows;
   int transposeAmount, randomizeMin, randomizeMax, fadeMin, fadeMax, collapseAmount;
+  float playheadY;
   float scaleMax;
   bool fadeMode, randomMode, haveHitBounds;
   signed char pendingStepUpdate;
diff --git a/src/gui/pattern.cpp b/src/gui/pattern.cpp
index 0a658a4e2..c0be247be 100644
--- a/src/gui/pattern.cpp
+++ b/src/gui/pattern.cpp
@@ -75,6 +75,10 @@ inline void FurnaceGUI::patternRow(int i, bool isPlaying, float lineHeight, int
   ImGui::TableNextRow(0,lineHeight);
   ImGui::TableNextColumn();
   float cursorPosY=ImGui::GetCursorPos().y-ImGui::GetScrollY();
+  // store playhead position on the screen
+  if (ord==playOrder && oldRow==i) {
+    playheadY=ImGui::GetCursorScreenPos().y;
+  }
   // check if the row is visible
   if (cursorPosY<-lineHeight || cursorPosY>ImGui::GetWindowSize().y) {
     return;
@@ -1483,7 +1487,7 @@ void FurnaceGUI::drawPattern() {
     if (fancyPattern) { // visualizer
       e->getCommandStream(cmdStream);
       ImDrawList* dl=ImGui::GetWindowDrawList();
-      ImVec2 off=ImVec2(0.0f,ImGui::GetWindowPos().y);
+      ImVec2 off=ImVec2(0.0f,0.0f);
 
       ImVec2 winMin=ImGui::GetWindowPos();
       ImVec2 winMax=ImVec2(
@@ -1616,7 +1620,7 @@ void FurnaceGUI::drawPattern() {
         for (int j=0; j<num; j++) {
           ImVec2 partPos=ImVec2(
             off.x+patChanX[i.chan]+fmod(rand(),width),
-            off.y+(ImGui::GetWindowHeight()*0.5f)+randRange(0,patFont->FontSize)
+            off.y+(playheadY)+randRange(0,patFont->FontSize)
           );
 
           if (partPos.x<winMin.x || partPos.y<winMin.y || partPos.x>winMax.x || partPos.y>winMax.y) continue;