• Benoît Knecht's avatar
    Use signals to readjust_view_after_zooming() · c9eef954
    Benoît Knecht authored and Sebastian Ramacher's avatar Sebastian Ramacher committed
    Instead of guesstimating the values of the scrollbars adjustments after
    a change in zoom level, connect callbacks to the "changed" GtkAdjustment
    event (which is emitted when the bounds or page_size of the adjustment
    change, e.g. when the zoom level changes), and compute the new values
    from there.
    The previous adjustment values are tracked in zathura->ui.hadjustment
    and zathura->ui.vadjustment (and updated by signal handlers as well), so
    that the view's position can be maintained while zooming.
    cb_view_hadjustment_changed() centers the page horizontally if a
    "best-fit" or "width" zoom is being performed, or if "zoom-center" is
    true; otherwise, it keeps the view horizontally centered around the same
    area of the page.
    cb_view_vadjustment_changed() always keeps the view vertically centered
    around the same area of the page.
    Many thanks to Marwan Tanager for thoroughly reviewing the various
    stages of this patch, and actually coming up with a working solution.
    Signed-off-by: Sebastian Ramacher's avatarSebastian Ramacher <sebastian+dev@ramacher.at>