Scrolling: Fixed scrolling centering API leading to non-integer scrolling values and initial cursor position. (#3073)

This would often get fixed after the fix item submission, but using the ImGuiListClipper as the first thing after Begin() could largely break size calculations. (#3073)

docs/CHANGELOG.txt

@@ -45,6 +45,9 @@ Other Changes:
   when the menu is not open. (#3030)
 - InputText: Fixed password fields displaying ASCII spaces as blanks instead of using the '*'
   glyph. (#2149, #515)
+- Scrolling: Fixed scrolling centering API leading to non-integer scrolling values and initial
+  cursor position. This would often get fixed after the fix item submission, but using the
+  ImGuiListClipper as the first thing after Begin() could largely break size calculations. (#3073)
 - Added optional support for Unicode plane 1-16 (#2538, #2541, #2815) [@cloudwu, @samhocevar]
   - Compile-time enable with '#define ImWchar ImWchar32' in imconfig.h.
   - Generally more consistent support for unsupported codepoints (0xFFFD), in particular when

imgui.cpp

@@ -7283,7 +7283,8 @@ static ImVec2 CalcNextScrollFromScrollTargetAndClamp(ImGuiWindow* window, bool s
             target_y = window->ContentSize.y + window->WindowPadding.y * 2.0f;
         scroll.y = target_y - cr_y * (window->SizeFull.y - window->ScrollbarSizes.y - decoration_up_height);
     }
-    scroll = ImMax(scroll, ImVec2(0.0f, 0.0f));
+    scroll.x = IM_FLOOR(ImMax(scroll.x, 0.0f));
+    scroll.y = IM_FLOOR(ImMax(scroll.y, 0.0f));
     if (!window->Collapsed && !window->SkipItems)
     {
         scroll.x = ImMin(scroll.x, window->ScrollMax.x);