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| author | Jiří Techet <techet@gmail.com> | 2013-05-08 01:45:00 +0200 |
|---|---|---|
| committer | Jiří Techet <techet@gmail.com> | 2013-05-08 01:45:00 +0200 |
| commit | a31db71dd4270bc68d80046d3538f7bf15319b1b (patch) | |
| tree | 7715d87dab3514e030fefed231b48767a3905ede | |
| parent | 6a90f2766d21cbc17d69c1f9ee22f998db3f49e5 (diff) | |
| download | libchamplain-a31db71dd4270bc68d80046d3538f7bf15319b1b.tar.gz | |
When zooming-in, recalculate viewport position from latitude/longitude to avoid rounding errors
| -rw-r--r-- | champlain/champlain-view.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/champlain/champlain-view.c b/champlain/champlain-view.c index 644e396..3bf7979 100644 --- a/champlain/champlain-view.c +++ b/champlain/champlain-view.c @@ -2490,6 +2490,8 @@ view_set_zoom_level_at (ChamplainView *view, gdouble new_x, new_y; gdouble offset_x = x; gdouble offset_y = y; + gdouble viewport_x, viewport_y; + gdouble deltazoom; if (zoom_level == priv->zoom_level || ZOOM_LEVEL_OUT_OF_RANGE (priv, zoom_level)) return FALSE; @@ -2506,9 +2508,14 @@ view_set_zoom_level_at (ChamplainView *view, if (CLUTTER_ACTOR_IS_REALIZED (view)) show_zoom_actor (view, zoom_level, offset_x, offset_y); - gdouble deltazoom = pow (2, -(gdouble)priv->zoom_level + (gdouble)zoom_level); - new_x = (priv->viewport_x + offset_x) * deltazoom - offset_x; - new_y = (priv->viewport_y + offset_y) * deltazoom - offset_y; + deltazoom = pow (2, -(gdouble)priv->zoom_level + (gdouble)zoom_level); + + /* priv->viewport_x, priv->viewport_y are in int which isn't sufficient precision + * when multiplied by deltazoom - recalculate them */ + viewport_x = champlain_map_source_get_x (priv->map_source, priv->zoom_level, priv->longitude); + viewport_y = champlain_map_source_get_y (priv->map_source, priv->zoom_level, priv->latitude); + new_x = (viewport_x + offset_x) * deltazoom - offset_x; + new_y = (viewport_y + offset_y) * deltazoom - offset_y; priv->zoom_level = zoom_level; |