Fix T84850: "Lock to Selection" causes unwanted jumps

Adding new tracks, mask points, mask primitives, changing selection was
causing an unwanted jumps in the view.

This change makes it so those operations are preserving view offset.

Differential Revision: https://developer.blender.org/D10146

1 files changed, 143 insertions, 4 deletions

diff --git a/source/blender/editors/space_clip/clip_utils.c b/source/blender/editors/space_clip/clip_utils.c
index c7f2a027ba8..faa3f18e8c1 100644
--- a/source/blender/editors/space_clip/clip_utils.c
+++ b/source/blender/editors/space_clip/clip_utils.c
@@ -27,10 +27,12 @@
 
 #include "BLI_listbase.h"
 #include "BLI_math.h"
+#include "BLI_rect.h"
 #include "BLI_utildefines.h"
 
 #include "BKE_animsys.h"
 #include "BKE_context.h"
+#include "BKE_mask.h"
 #include "BKE_movieclip.h"
 #include "BKE_tracking.h"
 
@@ -44,6 +46,7 @@
 #include "WM_types.h"
 
 #include "ED_clip.h"
+#include "ED_mask.h"
 #include "ED_screen.h"
 
 #include "UI_interface.h"
@@ -395,16 +398,152 @@ void clip_delete_plane_track(bContext *C, MovieClip *clip, MovieTrackingPlaneTra
   DEG_id_tag_update(&clip->id, 0);
 }
 
-void clip_view_center_to_point(SpaceClip *sc, float x, float y)
+/* Calculate space clip offset to be centered at the given point.  */
+void clip_view_offset_for_center_to_point(
+    SpaceClip *sc, const float x, const float y, float *r_offset_x, float *r_offset_y)
 {
   int width, height;
+  ED_space_clip_get_size(sc, &width, &height);
+
   float aspx, aspy;
+  ED_space_clip_get_aspect(sc, &aspx, &aspy);
+
+  *r_offset_x = (x - 0.5f) * width * aspx;
+  *r_offset_y = (y - 0.5f) * height * aspy;
+}
+
+void clip_view_center_to_point(SpaceClip *sc, float x, float y)
+{
+  clip_view_offset_for_center_to_point(sc, x, y, &sc->xof, &sc->yof);
+}
+
+static bool selected_tracking_boundbox(SpaceClip *sc, float min[2], float max[2])
+{
+  MovieClip *clip = ED_space_clip_get_clip(sc);
+  MovieTrackingTrack *track;
+  int width, height;
+  bool ok = false;
+  ListBase *tracksbase = BKE_tracking_get_active_tracks(&clip->tracking);
+  int framenr = ED_space_clip_get_clip_frame_number(sc);
+
+  INIT_MINMAX2(min, max);
 
   ED_space_clip_get_size(sc, &width, &height);
-  ED_space_clip_get_aspect(sc, &aspx, &aspy);
 
-  sc->xof = (x - 0.5f) * width * aspx;
-  sc->yof = (y - 0.5f) * height * aspy;
+  track = tracksbase->first;
+  while (track) {
+    if (TRACK_VIEW_SELECTED(sc, track)) {
+      MovieTrackingMarker *marker = BKE_tracking_marker_get(track, framenr);
+
+      if (marker) {
+        float pos[3];
+
+        pos[0] = marker->pos[0] + track->offset[0];
+        pos[1] = marker->pos[1] + track->offset[1];
+        pos[2] = 0.0f;
+
+        /* undistortion happens for normalized coords */
+        if (sc->user.render_flag & MCLIP_PROXY_RENDER_UNDISTORT) {
+          /* undistortion happens for normalized coords */
+          ED_clip_point_undistorted_pos(sc, pos, pos);
+        }
+
+        pos[0] *= width;
+        pos[1] *= height;
+
+        mul_v3_m4v3(pos, sc->stabmat, pos);
+
+        minmax_v2v2_v2(min, max, pos);
+
+        ok = true;
+      }
+    }
+
+    track = track->next;
+  }
+
+  return ok;
+}
+
+static bool selected_boundbox(const bContext *C, float min[2], float max[2], bool include_handles)
+{
+  SpaceClip *sc = CTX_wm_space_clip(C);
+  if (sc->mode == SC_MODE_TRACKING) {
+    return selected_tracking_boundbox(sc, min, max);
+  }
+
+  if (ED_mask_selected_minmax(C, min, max, include_handles)) {
+    MovieClip *clip = ED_space_clip_get_clip(sc);
+    int width, height;
+    ED_space_clip_get_size(sc, &width, &height);
+    BKE_mask_coord_to_movieclip(clip, &sc->user, min, min);
+    BKE_mask_coord_to_movieclip(clip, &sc->user, max, max);
+    min[0] *= width;
+    min[1] *= height;
+    max[0] *= width;
+    max[1] *= height;
+    return true;
+  }
+  return false;
+}
+
+bool clip_view_calculate_view_selection(
+    const bContext *C, bool fit, float *r_offset_x, float *r_offset_y, float *r_zoom)
+{
+  SpaceClip *sc = CTX_wm_space_clip(C);
+
+  int frame_width, frame_height;
+  ED_space_clip_get_size(sc, &frame_width, &frame_height);
+
+  if ((frame_width == 0) || (frame_height == 0) || (sc->clip == NULL)) {
+    return false;
+  }
+
+  /* NOTE: The `fit` argment is set to truth when doing "View to Selected" operator, and it set to
+   * false when this function is used for Lock-to-Selection functionality. When locking to
+   * selection the handles are to be ignored. So we can deriver the `include_handles` from `fit`.
+   *
+   * TODO(sergey): Make such decision more explicit. Maybe pass usecase for the calculation to tell
+   * operator from lock-to-selection apart. */
+  float min[2], max[2];
+  if (!selected_boundbox(C, min, max, fit)) {
+    return false;
+  }
+
+  /* center view */
+  clip_view_offset_for_center_to_point(sc,
+                                       (max[0] + min[0]) / (2 * frame_width),
+                                       (max[1] + min[1]) / (2 * frame_height),
+                                       r_offset_x,
+                                       r_offset_y);
+
+  const int w = max[0] - min[0];
+  const int h = max[1] - min[1];
+
+  /* set zoom to see all selection */
+  *r_zoom = sc->zoom;
+  if (w > 0 && h > 0) {
+    ARegion *region = CTX_wm_region(C);
+
+    int width, height;
+    float zoomx, zoomy, newzoom, aspx, aspy;
+
+    ED_space_clip_get_aspect(sc, &aspx, &aspy);
+
+    width = BLI_rcti_size_x(&region->winrct) + 1;
+    height = BLI_rcti_size_y(&region->winrct) + 1;
+
+    zoomx = (float)width / w / aspx;
+    zoomy = (float)height / h / aspy;
+
+    newzoom = 1.0f / power_of_2(1.0f / min_ff(zoomx, zoomy));
+
+    if (fit) {
+      *r_zoom = newzoom;
+    }
+  }
+
+  return true;
 }
 
 void clip_draw_sfra_efra(View2D *v2d, Scene *scene)