algo/scroll: improve directional moves (#13423)

1 files changed, 4 insertions, 2 deletions

diff --git a/src/layout/algorithm/tiled/scrolling/ScrollTapeController.cpp b/src/layout/algorithm/tiled/scrolling/ScrollTapeController.cpp
index c6cda4b5..77ab74b1 100644
--- a/src/layout/algorithm/tiled/scrolling/ScrollTapeController.cpp
+++ b/src/layout/algorithm/tiled/scrolling/ScrollTapeController.cpp
@@ -55,12 +55,14 @@ size_t CScrollTapeController::addStrip(float size) {
     return m_strips.size() - 1;
 }
 
-void CScrollTapeController::insertStrip(size_t afterIndex, float size) {
-    if (afterIndex >= m_strips.size()) {
+void CScrollTapeController::insertStrip(ssize_t afterIndex, float size) {
+    if (afterIndex >= sc<ssize_t>(m_strips.size())) {
         addStrip(size);
         return;
     }
 
+    afterIndex = std::clamp(afterIndex, -1L, sc<ssize_t>(INT32_MAX));
+
     SStripData newStrip;
     newStrip.size = size;
     m_strips.insert(m_strips.begin() + afterIndex + 1, newStrip);