Fixed Ctrl+Scroll zoom not working with cursor-centered focal point

[ikabrain]

Summary

Ctrl+Scroll zoom in Inlinea has been broken since at least GTK 4 was adopted. Holding Ctrl and scrolling over a PDF produced a ValueError: too many values to unpack (expected 2) on every single event, aborting the handler before the page had a chance to zoom. Because the traceback only surfaces when launching from a terminal rather than the desktop icon, most users would just see "Ctrl+Scroll does nothing" with no indication why.

Digging into the crash revealed a second problem underneath: even if the unpack were patched, zoom still would not have been cursor-centered. GtkEventControllerScroll in GTK 4 carries no pointer coordinates by design: get_position() returns False with NaN values on every scroll event. The existing surface-to-widget coordinate translation chain in on_scroll was permanently dead code; the viewport-center fallback fired on every Ctrl+Scroll regardless of where the cursor was!

This PR fixes both. The dead translation chain is replaced with a GtkEventControllerMotion that tracks the last known cursor position in widget-local coordinates. on_scroll reads from that directly, which gives _zoom_around_focal() the correct focal point on every event. The now-unused Graphene import and its gi.require_version call are removed as well.

Changes

• Added GtkEventControllerMotion to PDFView.__init__, connected to a new on_pointer_motion handler that stores the last cursor position as self._pointer_pos in widget-local coordinates.
• Replaced the dead get_position() / compute_point() translation chain in on_scroll with a one-liner that reads self._pointer_pos, falling back to the viewport center only when no pointer event has been recorded yet.
• Removed gi.require_version('Graphene', '1.0') and Graphene from the gi.repository import in ui/pdf_view.py; the translation chain was the only caller.

Tested locally on Arch Linux (python3 -m inlinea): Ctrl+Scroll zooms correctly and stays anchored to the cursor position. Plain scroll, header-bar zoom buttons, and pinch-to-zoom are all unaffected.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR simplifies Ctrl+scroll zoom focal point handling in the PDF view by removing Graphene/native coordinate transforms and instead tracking pointer position via a motion controller.

Changes:

• Remove Graphene GI dependency and related coordinate translation code.
• Track last pointer coordinates via Gtk.EventControllerMotion.
• Use tracked pointer position as the zoom focal point for Ctrl+scroll, falling back to viewport center.

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 3 comments.