From 30b2e1e7a36a59c19ad2475f31ef4baf2dcd1e8c Mon Sep 17 00:00:00 2001 From: Christian Hergert Date: Mon, 29 Jun 2020 15:01:26 -0700 Subject: [PATCH] textview: invalidate pixelcache for some invisible changes When making changes above the current visible region, we might need to invalidate the pixelcache as the Y positions will no longer match. This usually is not needed because changes are made interactively and are made onscreen. Other cases, though, can include an application changing the first line of the buffer automatically. We lose the ability to pixelcache well in this scenario, but that is unlikely an issue since rapid Y geometry resize or scrolling is less likely to be occuring. For situations where this is an issue, you can avoid removing the \n from the buffer so line heights are uneffected. Fixes #2882 --- gtk/gtktextview.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/gtk/gtktextview.c b/gtk/gtktextview.c index 408129bfef..a1c0bfce83 100644 --- a/gtk/gtktextview.c +++ b/gtk/gtktextview.c @@ -4668,6 +4668,24 @@ changed_handler (GtkTextLayout *layout, priv->yoffset += new_first_para_top - old_first_para_top; gtk_adjustment_set_value (text_view->priv->vadjustment, priv->yoffset); + + /* If the height changed above our current position, then we + * need to discard the pixelcache because things wont line nup + * anymore (even if we adjust the vadjustment). + * + * Generally this doesn't happen interactively because we keep + * the insert cursor on screen when making changes. It can + * happen when code changes the first line, for example, in an + * automated fashion. + * + * There is one case where this could be optimized out such as + * when delete-range is followed by insert-text and whole lines + * are removed. API consumers can always work around that by + * avoiding the removal of a \n so no effort is made here to + * handle that. + */ + if (gtk_widget_get_realized (widget)) + _gtk_pixel_cache_invalidate (text_view->priv->pixel_cache, NULL); } /* FIXME be smarter about which anchored widgets we update */