Keep points under mouse during edit operations.

WickedSmoke · WickedSmoke · commit a47dc154d20b · 2024-12-12T14:21:38.000-05:00
NOTE: Even when the old behavior is applied, points can still drift
away from the pointer with lots of moving while zooming. Is this due to the
relative tracking from the initial button press position?  Or just
cumulative rounding errors?
diff --git a/src/graphicswin.cpp b/src/graphicswin.cpp
@@ -728,7 +728,12 @@ void GraphicsWindow::ZoomToMouse(double zoomMultiplyer) {
     double offsetRight, offsetUp;
     double righti, upi;
 
-    if (! SS.zoomCenterNav) {
+    // Mouse edit operations currently track the pointer relative to the
+    // initial button press position, so zoomCenterNav is ignored during edits.
+    bool trackPointer = (pending.operation != Pending::NONE) ||
+                        (! SS.zoomCenterNav);
+
+    if (trackPointer) {
         offsetRight = offset.Dot(projRight);
         offsetUp    = offset.Dot(projUp);
 
@@ -745,7 +750,7 @@ void GraphicsWindow::ZoomToMouse(double zoomMultiplyer) {
 
     scale *= exp(0.1823216 * zoomMultiplyer); // ln(1.2) = 0.1823216
 
-    if (! SS.zoomCenterNav) {
+    if (trackPointer) {
         double rightf = currentMousePosition.x / scale - offsetRight;
         double upf    = currentMousePosition.y / scale - offsetUp;
 
