2D stabilization: flip orientation of the scale parameter

values > 1 will zoom in and values < 1 zoom out

Rationale: the changed orientation is more natural
from a user POV and doing it this way is also more
consistent with the calculation of the other
target_* parameters.

Compatibility: This will break *.blend files saved
with the previous version of this patch from the
last days (test period). It will *not* break any
old/migrated files: Previously, the DNA field "scale"
was only used to cache autoscale. Only with the
Stabilisator rework, "scale" becomes a first class
persistent DNA field. There is migration code to
init this field to 1.0

3 files changed, 26 insertions, 20 deletions

diff --git a/source/blender/blenkernel/intern/tracking_stabilize.c b/source/blender/blenkernel/intern/tracking_stabilize.c
index 0f047242f93..93addc47fe1 100644
--- a/source/blender/blenkernel/intern/tracking_stabilize.c
+++ b/source/blender/blenkernel/intern/tracking_stabilize.c
@@ -1020,13 +1020,13 @@ static void stabilization_calculate_data(StabContext *ctx,
                                          float *r_scale,
                                          float *r_angle)
 {
-	float target_pos[2];
+	float target_pos[2], target_scale;
 	float scaleinf = get_animated_scaleinf(ctx, framenr);
 
-	*r_scale = get_animated_target_scale(ctx,framenr);
-
 	if (ctx->stab->flag & TRACKING_STABILIZE_SCALE) {
-		*r_scale *= expf(scale_step * scaleinf);  /* Averaged in log scale */
+		*r_scale = expf(scale_step * scaleinf);  /* Averaged in log scale */
+	} else {
+		*r_scale = 1.0f;
 	}
 
 	mul_v2_fl(r_translation, get_animated_locinf(ctx, framenr));
@@ -1039,6 +1039,11 @@ static void stabilization_calculate_data(StabContext *ctx,
 	get_animated_target_pos(ctx, framenr, target_pos);
 	sub_v2_v2(r_translation, target_pos);
 	*r_angle -= get_animated_target_rot(ctx,framenr);
+	target_scale = get_animated_target_scale(ctx,framenr);
+	if (target_scale != 0.0f) {
+		*r_scale /= target_scale;
+		/* target_scale is an expected/intended reference zoom value*/
+	}
 
 	/* Convert from relative to absolute coordinates, square pixels. */
 	r_translation[0] *= (float)size * aspect;
@@ -1194,9 +1199,9 @@ static void stabilization_determine_safe_image_area(StabContext *ctx,
 					J = G - E;
 					K = G * F - E * H;
 
-					S = (dx * I + dy * J + K) / (-w * I - h * J);
+					S = (-w * I - h * J) / (dx * I + dy * J + K);
 
-					scale = min_ff(scale, S);
+					scale = max_ff(scale, S);
 				}
 			}
 		}
@@ -1205,7 +1210,7 @@ static void stabilization_determine_safe_image_area(StabContext *ctx,
 	stab->scale = scale;
 
 	if (stab->maxscale > 0.0f) {
-		stab->scale = max_ff(stab->scale, 1.0f / stab->maxscale);
+		stab->scale = min_ff(stab->scale, stab->maxscale);
 	}
 }
 
diff --git a/source/blender/blenloader/intern/versioning_270.c b/source/blender/blenloader/intern/versioning_270.c
index f6ac42c1941..1ef32d6f006 100644
--- a/source/blender/blenloader/intern/versioning_270.c
+++ b/source/blender/blenloader/intern/versioning_270.c
@@ -91,9 +91,6 @@ static void migrate_single_rot_stabilization_track_settings(MovieTrackingStabili
 		}
 	}
 	stab->rot_track = NULL; /* this field is now ignored */
-
-	/* by default show the track lists expanded, to improve "discoverability" */
-	stab->flag |= TRACKING_SHOW_STAB_TRACKS;
 }
 
 static void do_version_constraints_radians_degrees_270_1(ListBase *lb)
@@ -1369,13 +1366,17 @@ void blo_do_versions_270(FileData *fd, Library *UNUSED(lib), Main *main)
 			for (clip = main->movieclip.first; clip != NULL; clip = clip->id.next) {
 				if (clip->tracking.stabilization.rot_track) {
 					migrate_single_rot_stabilization_track_settings(&clip->tracking.stabilization);
-					if (!clip->tracking.stabilization.scale) {
-						/* ensure init.
-						 * Was previously used for autoscale only,
-						 * now used always (as "target scale") */
-						clip->tracking.stabilization.scale = 1.0f;
-					}
 				}
+				if (clip->tracking.stabilization.scale == 0.0f) {
+					/* ensure init.
+					 * Was previously used for autoscale only,
+					 * now used always (as "target scale") */
+					clip->tracking.stabilization.scale = 1.0f;
+				}
+				/* by default show the track lists expanded, to improve "discoverability" */
+				clip->tracking.stabilization.flag |= TRACKING_SHOW_STAB_TRACKS;
+				/* deprecated, not used anymore */
+				clip->tracking.stabilization.ok = false;
 			}
 		}
 	}
diff --git a/source/blender/makesrna/intern/rna_tracking.c b/source/blender/makesrna/intern/rna_tracking.c
index cbfebe5efc4..2d068bbab26 100644
--- a/source/blender/makesrna/intern/rna_tracking.c
+++ b/source/blender/makesrna/intern/rna_tracking.c
@@ -1768,7 +1768,7 @@ static void rna_def_trackingStabilization(BlenderRNA *brna)
 	prop = RNA_def_property(srna, "target_rotation", PROP_FLOAT, PROP_ANGLE);
 	RNA_def_property_float_sdna(prop, NULL, "target_rot");
 	RNA_def_property_range(prop, -FLT_MAX, FLT_MAX);
-	RNA_def_property_ui_range(prop, -FLT_MAX, FLT_MAX, 1, 3);
+	RNA_def_property_ui_range(prop, -FLT_MAX, FLT_MAX, 10.0f, 3);
 	RNA_def_property_ui_text(prop, "Expected Rotation",
 	                         "Rotation present on original shot, will be compensated (e.g. for deliberate tilting)");
 	RNA_def_property_update(prop, NC_MOVIECLIP | ND_DISPLAY, NULL);
@@ -1776,9 +1776,9 @@ static void rna_def_trackingStabilization(BlenderRNA *brna)
 	/* target scale */
 	prop = RNA_def_property(srna, "target_zoom", PROP_FLOAT, PROP_FACTOR);
 	RNA_def_property_float_sdna(prop, NULL, "scale");
-	RNA_def_property_range(prop, FLT_EPSILON, 100.0f);
-	RNA_def_property_ui_range(prop, 0.1f, 10.0f, 1, 3); /* increment in steps of 0.01. Show 3 digit after point */
-	RNA_def_property_ui_text(prop, "Expected Zoom",
+	RNA_def_property_range(prop, FLT_EPSILON, FLT_MAX);
+	RNA_def_property_ui_range(prop, 0.01f, 10.0f, 0.001f, 3); /* increment in steps of 0.001. Show 3 digit after point */
+	RNA_def_property_ui_text(prop, "Expected Scale",
 	                         "Explicitly scale resulting frame to compensate zoom of original shot");
 	RNA_def_property_update(prop, NC_MOVIECLIP | ND_DISPLAY, "rna_tracking_flushUpdate");