Cleanup: move animation snap utilities to a separate compilation unit

The snap functions of animation editors were scattered in
`transform_mode` and `transform_snap`.

1 files changed, 156 insertions, 0 deletions

diff --git a/source/blender/editors/transform/transform_snap_animation.c b/source/blender/editors/transform/transform_snap_animation.c
new file mode 100644
index 00000000000..ac7c47e408f
--- /dev/null
+++ b/source/blender/editors/transform/transform_snap_animation.c
@@ -0,0 +1,156 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup edtransform
+ */
+
+#include "DNA_anim_types.h"
+
+#include "BLI_math.h"
+
+#include "BKE_context.h"
+#include "BKE_nla.h"
+
+#include "ED_markers.h"
+#include "ED_screen.h"
+
+#include "transform.h"
+#include "transform_snap.h"
+
+/* -------------------------------------------------------------------- */
+/** \name Snappint in Anim Editors
+ * \{ */
+
+/**
+ * This function returns the snapping 'mode' for Animation Editors only.
+ * We cannot use the standard snapping due to NLA-strip scaling complexities.
+ *
+ * TODO: these modifier checks should be key-mappable.
+ */
+short getAnimEdit_SnapMode(TransInfo *t)
+{
+  short autosnap = SACTSNAP_OFF;
+
+  if (t->spacetype == SPACE_ACTION) {
+    SpaceAction *saction = (SpaceAction *)t->area->spacedata.first;
+
+    if (saction) {
+      autosnap = saction->autosnap;
+    }
+  }
+  else if (t->spacetype == SPACE_GRAPH) {
+    SpaceGraph *sipo = (SpaceGraph *)t->area->spacedata.first;
+
+    if (sipo) {
+      autosnap = sipo->autosnap;
+    }
+  }
+  else if (t->spacetype == SPACE_NLA) {
+    SpaceNla *snla = (SpaceNla *)t->area->spacedata.first;
+
+    if (snla) {
+      autosnap = snla->autosnap;
+    }
+  }
+  else {
+    autosnap = SACTSNAP_OFF;
+  }
+
+  /* toggle autosnap on/off
+   * - when toggling on, prefer nearest frame over 1.0 frame increments
+   */
+  if (t->modifiers & MOD_SNAP_INVERT) {
+    if (autosnap) {
+      autosnap = SACTSNAP_OFF;
+    }
+    else {
+      autosnap = SACTSNAP_FRAME;
+    }
+  }
+
+  return autosnap;
+}
+
+void snapFrameTransform(TransInfo *t,
+                        const eAnimEdit_AutoSnap autosnap,
+                        const bool is_frame_value,
+                        const float delta,
+                        /* return args */
+                        float *r_val)
+{
+  double val = delta;
+  switch (autosnap) {
+    case SACTSNAP_STEP:
+    case SACTSNAP_FRAME:
+      val = floor(val + 0.5);
+      break;
+    case SACTSNAP_MARKER:
+      /* snap to nearest marker */
+      /* TODO: need some more careful checks for where data comes from. */
+      val = ED_markers_find_nearest_marker_time(&t->scene->markers, (float)val);
+      break;
+    case SACTSNAP_SECOND:
+    case SACTSNAP_TSTEP: {
+      /* second step */
+      const Scene *scene = t->scene;
+      const double secf = FPS;
+      val = floor((val / secf) + 0.5);
+      if (is_frame_value) {
+        val *= secf;
+      }
+      break;
+    }
+    case SACTSNAP_OFF: {
+      break;
+    }
+  }
+  *r_val = (float)val;
+}
+
+/* This function is used by Animation Editor specific transform functions to do
+ * the Snap Keyframe to Nearest Frame/Marker
+ */
+void doAnimEdit_SnapFrame(
+    TransInfo *t, TransData *td, TransData2D *td2d, AnimData *adt, short autosnap)
+{
+  if (autosnap != SACTSNAP_OFF) {
+    float val;
+
+    /* convert frame to nla-action time (if needed) */
+    if (adt && (t->spacetype != SPACE_SEQ)) {
+      val = BKE_nla_tweakedit_remap(adt, *(td->val), NLATIME_CONVERT_MAP);
+    }
+    else {
+      val = *(td->val);
+    }
+
+    snapFrameTransform(t, autosnap, true, val, &val);
+
+    /* convert frame out of nla-action time */
+    if (adt && (t->spacetype != SPACE_SEQ)) {
+      *(td->val) = BKE_nla_tweakedit_remap(adt, val, NLATIME_CONVERT_UNMAP);
+    }
+    else {
+      *(td->val) = val;
+    }
+  }
+}
+
+/** \} */