Editor 2D: Change pixel alignment strategy, fix jittering in high zoom

Alignment of scene pixels on screen pixel ensure a crisp rendering of small features (such as text). Unfortunately, alignment of top left pixel on screen adds a lot of jittering when zooming at high zoom factor.

This change allow to snap the top left scene pixel on the closest screen pixel (not only the top-left most), and we do so only when the scale factor is an integer.
This commit is contained in:
johan 2020-03-18 02:05:23 -04:00
parent 0d907a6320
commit 1c02906a6f
1 changed files with 14 additions and 4 deletions

View File

@ -4306,10 +4306,20 @@ void CanvasItemEditor::_zoom_on_position(float p_zoom, Point2 p_position) {
float prev_zoom = zoom;
zoom = p_zoom;
Point2 ofs = p_position;
ofs = ofs / prev_zoom - ofs / zoom;
view_offset.x = Math::round(view_offset.x + ofs.x);
view_offset.y = Math::round(view_offset.y + ofs.y);
view_offset += p_position / prev_zoom - p_position / zoom;
// We want to align in-scene pixels to screen pixels, this prevents blurry rendering
// in small details (texts, lines).
// This correction adds a jitter movement when zooming, so we correct only when the
// zoom factor is an integer. (in the other cases, all pixels won't be aligned anyway)
float closest_zoom_factor = Math::round(zoom);
if (Math::is_zero_approx(zoom - closest_zoom_factor)) {
// make sure scene pixel at view_offset is aligned on a screen pixel
Vector2 view_offset_int = view_offset.floor();
Vector2 view_offset_frac = view_offset - view_offset_int;
view_offset = view_offset_int + (view_offset_frac * closest_zoom_factor).round() / closest_zoom_factor;
}
_update_zoom_label();
update_viewport();