VSE: Image transform tools

Add tools for image manipulation in sequencer preview region.

This includes:
- Translate, rotate and resize operators, tools and gizmos
- Origin for image transformation
- Median point and individual origins pivot modes
- Select and Box select operator works in preview
- Image overlay drawing

ref T90156

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D12105

15 files changed, 562 insertions, 34 deletions

diff --git a/source/blender/editors/animation/anim_ops.c b/source/blender/editors/animation/anim_ops.c
index 450d7cd100e..b4ea33920b2 100644
--- a/source/blender/editors/animation/anim_ops.c
+++ b/source/blender/editors/animation/anim_ops.c
@@ -241,6 +241,11 @@ static bool use_sequencer_snapping(bContext *C)
 /* Modal Operator init */
 static int change_frame_invoke(bContext *C, wmOperator *op, const wmEvent *event)
 {
+  ARegion *region = CTX_wm_region(C);
+  if (CTX_wm_space_seq(C) != NULL && region->regiontype == RGN_TYPE_PREVIEW) {
+    return OPERATOR_CANCELLED;
+  }
+
   /* Change to frame that mouse is over before adding modal handler,
    * as user could click on a single frame (jump to frame) as well as
    * click-dragging over a range (modal scrubbing).
diff --git a/source/blender/editors/space_sequencer/sequencer_draw.c b/source/blender/editors/space_sequencer/sequencer_draw.c
index 5b39feacfe3..e063e12a9a8 100644
--- a/source/blender/editors/space_sequencer/sequencer_draw.c
+++ b/source/blender/editors/space_sequencer/sequencer_draw.c
@@ -71,6 +71,7 @@
 #include "BIF_glutil.h"
 
 #include "SEQ_effects.h"
+#include "SEQ_iterator.h"
 #include "SEQ_prefetch.h"
 #include "SEQ_proxy.h"
 #include "SEQ_relations.h"
@@ -2056,6 +2057,64 @@ static int sequencer_draw_get_transform_preview_frame(Scene *scene)
   return preview_frame;
 }
 
+static void seq_draw_image_origin_and_outline(const bContext *C, Sequence *seq)
+{
+  SpaceSeq *sseq = CTX_wm_space_seq(C);
+  if ((seq->flag & SELECT) == 0) {
+    return;
+  }
+  if (ED_screen_animation_no_scrub(CTX_wm_manager(C))) {
+    return;
+  }
+  if ((sseq->flag & SEQ_SHOW_OVERLAY) == 0 ||
+      (sseq->preview_overlay.flag & SEQ_PREVIEW_SHOW_OUTLINE_SELECTED) == 0) {
+    return;
+  }
+  if (ELEM(sseq->mainb, SEQ_DRAW_IMG_WAVEFORM, SEQ_DRAW_IMG_VECTORSCOPE, SEQ_DRAW_IMG_HISTOGRAM)) {
+    return;
+  }
+
+  float origin[2];
+  SEQ_image_transform_origin_offset_pixelspace_get(CTX_data_scene(C), seq, origin);
+
+  /* Origin. */
+  GPUVertFormat *format = immVertexFormat();
+  uint pos = GPU_vertformat_attr_add(format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
+  immBindBuiltinProgram(GPU_SHADER_2D_POINT_UNIFORM_SIZE_UNIFORM_COLOR_OUTLINE_AA);
+  immUniform1f("outlineWidth", 1.5f);
+  immUniformColor3f(1.0f, 1.0f, 1.0f);
+  immUniform4f("outlineColor", 0.0f, 0.0f, 0.0f, 1.0f);
+  immUniform1f("size", 15.0f * U.pixelsize);
+  immBegin(GPU_PRIM_POINTS, 1);
+  immVertex2f(pos, origin[0], origin[1]);
+  immEnd();
+  immUnbindProgram();
+
+  /* Outline. */
+  float seq_image_quad[4][2];
+  SEQ_image_transform_final_quad_get(CTX_data_scene(C), seq, seq_image_quad);
+
+  GPU_line_smooth(true);
+  GPU_blend(GPU_BLEND_ALPHA);
+  GPU_line_width(2);
+  immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);
+
+  float col[3];
+  UI_GetThemeColor3fv(TH_SEQ_SELECTED, col);
+  immUniformColor3fv(col);
+  immUniform1f("lineWidth", U.pixelsize);
+  immBegin(GPU_PRIM_LINE_LOOP, 4);
+  immVertex2f(pos, seq_image_quad[0][0], seq_image_quad[0][1]);
+  immVertex2f(pos, seq_image_quad[1][0], seq_image_quad[1][1]);
+  immVertex2f(pos, seq_image_quad[2][0], seq_image_quad[2][1]);
+  immVertex2f(pos, seq_image_quad[3][0], seq_image_quad[3][1]);
+  immEnd();
+  immUnbindProgram();
+  GPU_line_width(1);
+  GPU_blend(GPU_BLEND_NONE);
+  GPU_line_smooth(false);
+}
+
 void sequencer_draw_preview(const bContext *C,
                             Scene *scene,
                             ARegion *region,
@@ -2132,9 +2191,17 @@ void sequencer_draw_preview(const bContext *C,
     sequencer_draw_borders_overlay(sseq, v2d, scene);
   }
 
+  SeqCollection *collection = SEQ_query_rendered_strips(&scene->ed->seqbase, timeline_frame, 0);
+  Sequence *seq;
+  SEQ_ITERATOR_FOREACH (seq, collection) {
+    seq_draw_image_origin_and_outline(C, seq);
+  }
+  SEQ_collection_free(collection);
+
   if (draw_gpencil && show_imbuf && (sseq->flag & SEQ_SHOW_OVERLAY)) {
     sequencer_draw_gpencil_overlay(C);
   }
+
 #if 0
   sequencer_draw_maskedit(C, scene, region, sseq);
 #endif
diff --git a/source/blender/editors/space_sequencer/sequencer_select.c b/source/blender/editors/space_sequencer/sequencer_select.c
index 80d3e2cbdaa..aa6599a7c53 100644
--- a/source/blender/editors/space_sequencer/sequencer_select.c
+++ b/source/blender/editors/space_sequencer/sequencer_select.c
@@ -44,6 +44,7 @@
 #include "SEQ_sequencer.h"
 #include "SEQ_time.h"
 #include "SEQ_transform.h"
+#include "SEQ_utils.h"
 
 /* For menu, popup, icons, etc. */
 
@@ -385,6 +386,20 @@ void recurs_sel_seq(Sequence *seq_meta)
   }
 }
 
+static bool seq_point_image_isect(const Scene *scene, const Sequence *seq, float point[2])
+{
+  float seq_image_quad[4][2];
+  SEQ_image_transform_final_quad_get(scene, seq, seq_image_quad);
+  return isect_point_quad_v2(
+      point, seq_image_quad[0], seq_image_quad[1], seq_image_quad[2], seq_image_quad[3]);
+}
+
+static void sequencer_select_do_updates(bContext *C, Scene *scene)
+{
+  ED_outliner_select_sync_from_sequence_tag(C);
+  WM_event_add_notifier(C, NC_SCENE | ND_SEQUENCER | NA_SELECTED, scene);
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */
@@ -523,12 +538,6 @@ static void sequencer_select_set_active(Scene *scene, Sequence *seq)
   recurs_sel_seq(seq);
 }
 
-static void sequencer_select_do_updates(bContext *C, Scene *scene)
-{
-  ED_outliner_select_sync_from_sequence_tag(C);
-  WM_event_add_notifier(C, NC_SCENE | ND_SEQUENCER | NA_SELECTED, scene);
-}
-
 static void sequencer_select_side_of_frame(const bContext *C,
                                            const View2D *v2d,
                                            const int mval[2],
@@ -626,6 +635,45 @@ static void sequencer_select_linked_handle(const bContext *C,
   }
 }
 
+/* Check if click happened on image which belongs to strip. If multiple strips are found, loop
+ * through them in order. */
+static Sequence *seq_select_seq_from_preview(const bContext *C, const int mval[2])
+{
+  Scene *scene = CTX_data_scene(C);
+  Editing *ed = SEQ_editing_get(scene);
+  ListBase *seqbase = SEQ_active_seqbase_get(ed);
+  SpaceSeq *sseq = CTX_wm_space_seq(C);
+  View2D *v2d = UI_view2d_fromcontext(C);
+
+  float mouseco_view[2];
+  UI_view2d_region_to_view(v2d, mval[0], mval[1], &mouseco_view[0], &mouseco_view[1]);
+
+  SeqCollection *strips = SEQ_query_rendered_strips(seqbase, scene->r.cfra, sseq->chanshown);
+  ListBase strips_ordered = {NULL};
+  Sequence *seq;
+  SEQ_ITERATOR_FOREACH (seq, strips) {
+    if (seq_point_image_isect(scene, seq, mouseco_view)) {
+      BLI_remlink(seqbase, seq);
+      BLI_addtail(&strips_ordered, seq);
+    }
+  }
+  SEQ_collection_free(strips);
+  SEQ_sort(&strips_ordered);
+
+  Sequence *seq_active = SEQ_select_active_get(scene);
+  Sequence *seq_select = strips_ordered.first;
+  LISTBASE_FOREACH (Sequence *, seq_iter, &strips_ordered) {
+    if (seq_iter == seq_active && seq_iter->next != NULL) {
+      seq_select = seq_iter->next;
+      break;
+    }
+  }
+
+  BLI_movelisttolist(seqbase, &strips_ordered);
+
+  return seq_select;
+}
+
 static bool element_already_selected(const Sequence *seq, const int handle_clicked)
 {
   const bool handle_already_selected = ((handle_clicked == SEQ_SIDE_LEFT) &&
@@ -680,8 +728,15 @@ static int sequencer_select_exec(bContext *C, wmOperator *op)
   mval[0] = RNA_int_get(op->ptr, "mouse_x");
   mval[1] = RNA_int_get(op->ptr, "mouse_y");
 
-  int handle_clicked;
-  Sequence *seq = find_nearest_seq(scene, v2d, &handle_clicked, mval);
+  ARegion *region = CTX_wm_region(C);
+  int handle_clicked = SEQ_SIDE_NONE;
+  Sequence *seq = NULL;
+  if (region->regiontype == RGN_TYPE_PREVIEW) {
+    seq = seq_select_seq_from_preview(C, mval);
+  }
+  else {
+    seq = find_nearest_seq(scene, v2d, &handle_clicked, mval);
+  }
 
   /* NOTE: `side_of_frame` and `linked_time` functionality is designed to be shared on one keymap,
    * therefore both properties can be true at the same time. */
@@ -1311,6 +1366,47 @@ void SEQUENCER_OT_select_side(wmOperatorType *ot)
 /** \name Box Select Operator
  * \{ */
 
+static bool seq_box_select_rect_image_isect(const Scene *scene, const Sequence *seq, rctf *rect)
+{
+  float seq_image_quad[4][2];
+  SEQ_image_transform_final_quad_get(scene, seq, seq_image_quad);
+  float rect_quad[4][2] = {{rect->xmax, rect->ymax},
+                           {rect->xmax, rect->ymin},
+                           {rect->xmin, rect->ymin},
+                           {rect->xmin, rect->ymax}};
+
+  return seq_point_image_isect(scene, seq, rect_quad[0]) ||
+         seq_point_image_isect(scene, seq, rect_quad[1]) ||
+         seq_point_image_isect(scene, seq, rect_quad[2]) ||
+         seq_point_image_isect(scene, seq, rect_quad[3]) ||
+         isect_point_quad_v2(
+             seq_image_quad[0], rect_quad[0], rect_quad[1], rect_quad[2], rect_quad[3]) ||
+         isect_point_quad_v2(
+             seq_image_quad[1], rect_quad[0], rect_quad[1], rect_quad[2], rect_quad[3]) ||
+         isect_point_quad_v2(
+             seq_image_quad[2], rect_quad[0], rect_quad[1], rect_quad[2], rect_quad[3]) ||
+         isect_point_quad_v2(
+             seq_image_quad[3], rect_quad[0], rect_quad[1], rect_quad[2], rect_quad[3]);
+}
+
+static void seq_box_select_seq_from_preview(const bContext *C, rctf *rect)
+{
+  Scene *scene = CTX_data_scene(C);
+  Editing *ed = SEQ_editing_get(scene);
+  ListBase *seqbase = SEQ_active_seqbase_get(ed);
+  SpaceSeq *sseq = CTX_wm_space_seq(C);
+
+  SeqCollection *strips = SEQ_query_rendered_strips(seqbase, scene->r.cfra, sseq->chanshown);
+  Sequence *seq;
+  SEQ_ITERATOR_FOREACH (seq, strips) {
+    if (seq_box_select_rect_image_isect(scene, seq, rect)) {
+      seq->flag |= SELECT;
+    }
+  }
+
+  SEQ_collection_free(strips);
+}
+
 static int sequencer_box_select_exec(bContext *C, wmOperator *op)
 {
   Scene *scene = CTX_data_scene(C);
@@ -1333,6 +1429,13 @@ static int sequencer_box_select_exec(bContext *C, wmOperator *op)
   WM_operator_properties_border_to_rctf(op, &rectf);
   UI_view2d_region_to_view_rctf(v2d, &rectf, &rectf);
 
+  ARegion *region = CTX_wm_region(C);
+  if (region->regiontype == RGN_TYPE_PREVIEW) {
+    seq_box_select_seq_from_preview(C, &rectf);
+    sequencer_select_do_updates(C, scene);
+    return OPERATOR_FINISHED;
+  }
+
   LISTBASE_FOREACH (Sequence *, seq, ed->seqbasep) {
     rctf rq;
     seq_rectf(seq, &rq);
@@ -1378,9 +1481,7 @@ static int sequencer_box_select_exec(bContext *C, wmOperator *op)
     }
   }
 
-  ED_outliner_select_sync_from_sequence_tag(C);
-
-  WM_event_add_notifier(C, NC_SCENE | ND_SEQUENCER | NA_SELECTED, scene);
+  sequencer_select_do_updates(C, scene);
 
   return OPERATOR_FINISHED;
 }
diff --git a/source/blender/editors/space_sequencer/space_sequencer.c b/source/blender/editors/space_sequencer/space_sequencer.c
index 0d09f2564e8..cb5fe6f0ef3 100644
--- a/source/blender/editors/space_sequencer/space_sequencer.c
+++ b/source/blender/editors/space_sequencer/space_sequencer.c
@@ -42,6 +42,7 @@
 
 #include "ED_screen.h"
 #include "ED_space_api.h"
+#include "ED_transform.h"
 #include "ED_view3d.h"
 #include "ED_view3d_offscreen.h" /* Only for sequencer view3d drawing callback. */
 
@@ -98,10 +99,11 @@ static SpaceLink *sequencer_create(const ScrArea *UNUSED(area), const Scene *sce
   sseq->chanshown = 0;
   sseq->view = SEQ_VIEW_SEQUENCE;
   sseq->mainb = SEQ_DRAW_IMG_IMBUF;
-  sseq->flag = SEQ_PREVIEW_SHOW_GPENCIL | SEQ_USE_ALPHA | SEQ_SHOW_MARKERS |
-               SEQ_TIMELINE_SHOW_FCURVES | SEQ_ZOOM_TO_FIT | SEQ_SHOW_OVERLAY |
-               SEQ_TIMELINE_SHOW_STRIP_NAME | SEQ_TIMELINE_SHOW_STRIP_SOURCE |
-               SEQ_TIMELINE_SHOW_STRIP_DURATION | SEQ_TIMELINE_SHOW_GRID;
+  sseq->flag = SEQ_USE_ALPHA | SEQ_SHOW_MARKERS | SEQ_ZOOM_TO_FIT | SEQ_SHOW_OVERLAY;
+  sseq->preview_overlay.flag = SEQ_PREVIEW_SHOW_GPENCIL | SEQ_PREVIEW_SHOW_OUTLINE_SELECTED;
+  sseq->timeline_overlay.flag = SEQ_TIMELINE_SHOW_STRIP_NAME | SEQ_TIMELINE_SHOW_STRIP_SOURCE |
+                                SEQ_TIMELINE_SHOW_STRIP_DURATION | SEQ_TIMELINE_SHOW_GRID |
+                                SEQ_TIMELINE_SHOW_FCURVES;
 
   /* Tool header. */
   region = MEM_callocN(sizeof(ARegion), "tool header for sequencer");
@@ -481,11 +483,72 @@ static void SEQUENCER_GGT_navigate(wmGizmoGroupType *gzgt)
   VIEW2D_GGT_navigate_impl(gzgt, "SEQUENCER_GGT_navigate");
 }
 
+static void SEQUENCER_GGT_gizmo2d(wmGizmoGroupType *gzgt)
+{
+  gzgt->name = "Sequencer Transform Gizmo";
+  gzgt->idname = "SEQUENCER_GGT_gizmo2d";
+
+  gzgt->flag |= (WM_GIZMOGROUPTYPE_TOOL_FALLBACK_KEYMAP |
+                 WM_GIZMOGROUPTYPE_DELAY_REFRESH_FOR_TWEAK);
+
+  gzgt->gzmap_params.spaceid = SPACE_SEQ;
+  gzgt->gzmap_params.regionid = RGN_TYPE_PREVIEW;
+
+  ED_widgetgroup_gizmo2d_xform_callbacks_set(gzgt);
+}
+
+static void SEQUENCER_GGT_gizmo2d_translate(wmGizmoGroupType *gzgt)
+{
+  gzgt->name = "Sequencer Translate Gizmo";
+  gzgt->idname = "SEQUENCER_GGT_gizmo2d_translate";
+
+  gzgt->flag |= (WM_GIZMOGROUPTYPE_TOOL_FALLBACK_KEYMAP |
+                 WM_GIZMOGROUPTYPE_DELAY_REFRESH_FOR_TWEAK);
+
+  gzgt->gzmap_params.spaceid = SPACE_SEQ;
+  gzgt->gzmap_params.regionid = RGN_TYPE_PREVIEW;
+
+  ED_widgetgroup_gizmo2d_xform_no_cage_callbacks_set(gzgt);
+}
+
+static void SEQUENCER_GGT_gizmo2d_resize(wmGizmoGroupType *gzgt)
+{
+  gzgt->name = "Sequencer Transform Gizmo Resize";
+  gzgt->idname = "SEQUENCER_GGT_gizmo2d_resize";
+
+  gzgt->flag |= (WM_GIZMOGROUPTYPE_TOOL_FALLBACK_KEYMAP |
+                 WM_GIZMOGROUPTYPE_DELAY_REFRESH_FOR_TWEAK);
+
+  gzgt->gzmap_params.spaceid = SPACE_SEQ;
+  gzgt->gzmap_params.regionid = RGN_TYPE_PREVIEW;
+
+  ED_widgetgroup_gizmo2d_resize_callbacks_set(gzgt);
+}
+
+static void SEQUENCER_GGT_gizmo2d_rotate(wmGizmoGroupType *gzgt)
+{
+  gzgt->name = "Sequencer Transform Gizmo Resize";
+  gzgt->idname = "SEQUENCER_GGT_gizmo2d_rotate";
+
+  gzgt->flag |= (WM_GIZMOGROUPTYPE_TOOL_FALLBACK_KEYMAP |
+                 WM_GIZMOGROUPTYPE_DELAY_REFRESH_FOR_TWEAK);
+
+  gzgt->gzmap_params.spaceid = SPACE_SEQ;
+  gzgt->gzmap_params.regionid = RGN_TYPE_PREVIEW;
+
+  ED_widgetgroup_gizmo2d_rotate_callbacks_set(gzgt);
+}
+
 static void sequencer_gizmos(void)
 {
   wmGizmoMapType *gzmap_type = WM_gizmomaptype_ensure(
       &(const struct wmGizmoMapType_Params){SPACE_SEQ, RGN_TYPE_PREVIEW});
 
+  WM_gizmogrouptype_append(SEQUENCER_GGT_gizmo2d);
+  WM_gizmogrouptype_append(SEQUENCER_GGT_gizmo2d_translate);
+  WM_gizmogrouptype_append(SEQUENCER_GGT_gizmo2d_resize);
+  WM_gizmogrouptype_append(SEQUENCER_GGT_gizmo2d_rotate);
+
   WM_gizmogrouptype_append_and_link(gzmap_type, SEQUENCER_GGT_navigate);
 }
 
@@ -742,6 +805,8 @@ static void sequencer_preview_region_listener(const wmRegionListenerParams *para
   ARegion *region = params->region;
   wmNotifier *wmn = params->notifier;
 
+  WM_gizmomap_tag_refresh(region->gizmo_map);
+
   /* Context changes. */
   switch (wmn->category) {
     case NC_GPENCIL:
diff --git a/source/blender/editors/transform/CMakeLists.txt b/source/blender/editors/transform/CMakeLists.txt
index e9efed3cd61..64a720322c1 100644
--- a/source/blender/editors/transform/CMakeLists.txt
+++ b/source/blender/editors/transform/CMakeLists.txt
@@ -60,6 +60,7 @@ set(SRC
   transform_convert_particle.c
   transform_convert_sculpt.c
   transform_convert_sequencer.c
+  transform_convert_sequencer_image.c
   transform_convert_tracking.c
   transform_draw_cursors.c
   transform_generics.c
diff --git a/source/blender/editors/transform/transform.c b/source/blender/editors/transform/transform.c
index 58491f8c2d3..e58e524e341 100644
--- a/source/blender/editors/transform/transform.c
+++ b/source/blender/editors/transform/transform.c
@@ -1703,11 +1703,13 @@ bool initTransform(bContext *C, TransInfo *t, wmOperator *op, const wmEvent *eve
     t->draw_handle_cursor = WM_paint_cursor_activate(
         SPACE_TYPE_ANY, RGN_TYPE_ANY, transform_draw_cursor_poll, transform_draw_cursor_draw, t);
   }
-  else if (t->spacetype == SPACE_SEQ) {
-    t->draw_handle_view = ED_region_draw_cb_activate(
-        t->region->type, drawTransformView, t, REGION_DRAW_POST_VIEW);
-  }
-  else if (ELEM(t->spacetype, SPACE_IMAGE, SPACE_CLIP, SPACE_NODE, SPACE_GRAPH, SPACE_ACTION)) {
+  else if (ELEM(t->spacetype,
+                SPACE_IMAGE,
+                SPACE_CLIP,
+                SPACE_NODE,
+                SPACE_GRAPH,
+                SPACE_ACTION,
+                SPACE_SEQ)) {
     t->draw_handle_view = ED_region_draw_cb_activate(
         t->region->type, drawTransformView, t, REGION_DRAW_POST_VIEW);
     t->draw_handle_cursor = WM_paint_cursor_activate(
diff --git a/source/blender/editors/transform/transform.h b/source/blender/editors/transform/transform.h
index d1a1937cef1..7f4e533ccd7 100644
--- a/source/blender/editors/transform/transform.h
+++ b/source/blender/editors/transform/transform.h
@@ -87,15 +87,16 @@ typedef enum {
   CTX_PAINT_CURVE = (1 << 7),
   CTX_POSE_BONE = (1 << 8),
   CTX_TEXTURE_SPACE = (1 << 9),
+  CTX_SEQUENCER_IMAGE = (1 << 10),
 
-  CTX_NO_PET = (1 << 10),
-  CTX_AUTOCONFIRM = (1 << 11),
+  CTX_NO_PET = (1 << 11),
+  CTX_AUTOCONFIRM = (1 << 12),
   /** When transforming object's, adjust the object data so it stays in the same place. */
-  CTX_OBMODE_XFORM_OBDATA = (1 << 12),
+  CTX_OBMODE_XFORM_OBDATA = (1 << 13),
   /** Transform object parents without moving their children. */
-  CTX_OBMODE_XFORM_SKIP_CHILDREN = (1 << 13),
+  CTX_OBMODE_XFORM_SKIP_CHILDREN = (1 << 14),
   /** Enable edge scrolling in 2D views */
-  CTX_VIEW2D_EDGE_PAN = (1 << 14),
+  CTX_VIEW2D_EDGE_PAN = (1 << 15),
 } eTContext;
 
 /** #TransInfo.flag */
@@ -240,6 +241,7 @@ typedef enum {
   TC_PARTICLE_VERTS,
   TC_SCULPT,
   TC_SEQ_DATA,
+  TC_SEQ_IMAGE_DATA,
   TC_TRACKING_DATA,
 } eTConvertType;
 
diff --git a/source/blender/editors/transform/transform_convert.c b/source/blender/editors/transform/transform_convert.c
index d756e2c90a6..557fa79e7ac 100644
--- a/source/blender/editors/transform/transform_convert.c
+++ b/source/blender/editors/transform/transform_convert.c
@@ -955,6 +955,7 @@ void special_aftertrans_update(bContext *C, TransInfo *t)
     case TC_OBJECT_TEXSPACE:
     case TC_PAINT_CURVE_VERTS:
     case TC_PARTICLE_VERTS:
+    case TC_SEQ_IMAGE_DATA:
     case TC_NONE:
     default:
       break;
@@ -1042,6 +1043,7 @@ static void init_proportional_edit(TransInfo *t)
     case TC_PAINT_CURVE_VERTS:
     case TC_SCULPT:
     case TC_SEQ_DATA:
+    case TC_SEQ_IMAGE_DATA:
     case TC_TRACKING_DATA:
     case TC_NONE:
     default:
@@ -1120,6 +1122,7 @@ static void init_TransDataContainers(TransInfo *t,
     case TC_PARTICLE_VERTS:
     case TC_SCULPT:
     case TC_SEQ_DATA:
+    case TC_SEQ_IMAGE_DATA:
     case TC_TRACKING_DATA:
     case TC_NONE:
     default:
@@ -1204,6 +1207,7 @@ static eTFlag flags_from_data_type(eTConvertType data_type)
     case TC_NODE_DATA:
     case TC_PAINT_CURVE_VERTS:
     case TC_SEQ_DATA:
+    case TC_SEQ_IMAGE_DATA:
     case TC_TRACKING_DATA:
       return T_POINTS | T_2D_EDIT;
     case TC_ARMATURE_VERTS:
@@ -1282,7 +1286,12 @@ static eTConvertType convert_type_get(const TransInfo *t, Object **r_obj_armatur
     convert_type = TC_NLA_DATA;
   }
   else if (t->spacetype == SPACE_SEQ) {
-    convert_type = TC_SEQ_DATA;
+    if (t->options & CTX_SEQUENCER_IMAGE) {
+      convert_type = TC_SEQ_IMAGE_DATA;
+    }
+    else {
+      convert_type = TC_SEQ_DATA;
+    }
   }
   else if (t->spacetype == SPACE_GRAPH) {
     convert_type = TC_GRAPH_EDIT_DATA;
@@ -1470,6 +1479,10 @@ void createTransData(bContext *C, TransInfo *t)
       t->num.flag |= NUM_NO_FRACTION; /* sequencer has no use for floating point transform. */
       createTransSeqData(t);
       break;
+    case TC_SEQ_IMAGE_DATA:
+      t->obedit_type = -1;
+      createTransSeqImageData(t);
+      break;
     case TC_TRACKING_DATA:
       createTransTrackingData(C, t);
       break;
@@ -1746,6 +1759,9 @@ void recalcData(TransInfo *t)
     case TC_SEQ_DATA:
       recalcData_sequencer(t);
       break;
+    case TC_SEQ_IMAGE_DATA:
+      recalcData_sequencer_image(t);
+      break;
     case TC_TRACKING_DATA:
       recalcData_tracking(t);
       break;
diff --git a/source/blender/editors/transform/transform_convert.h b/source/blender/editors/transform/transform_convert.h
index 9cb0400cad9..66d84bca2d2 100644
--- a/source/blender/editors/transform/transform_convert.h
+++ b/source/blender/editors/transform/transform_convert.h
@@ -218,6 +218,10 @@ void createTransSeqData(TransInfo *t);
 void recalcData_sequencer(TransInfo *t);
 void special_aftertrans_update__sequencer(bContext *C, TransInfo *t);
 
+/* transform_convert_sequencer_image.c */
+void createTransSeqImageData(TransInfo *t);
+void recalcData_sequencer_image(TransInfo *t);
+
 /* transform_convert_tracking.c */
 void createTransTrackingData(bContext *C, TransInfo *t);
 void recalcData_tracking(TransInfo *t);
diff --git a/source/blender/editors/transform/transform_convert_sequencer_image.c b/source/blender/editors/transform/transform_convert_sequencer_image.c
new file mode 100644
index 00000000000..465f8b9a694
--- /dev/null
+++ b/source/blender/editors/transform/transform_convert_sequencer_image.c
@@ -0,0 +1,195 @@
+/*
+ * 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) 2021 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup edtransform
+ */
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_space_types.h"
+
+#include "BLI_listbase.h"
+#include "BLI_math.h"
+
+#include "BKE_context.h"
+#include "BKE_report.h"
+
+#include "SEQ_iterator.h"
+#include "SEQ_relations.h"
+#include "SEQ_sequencer.h"
+#include "SEQ_time.h"
+#include "SEQ_transform.h"
+#include "SEQ_utils.h"
+
+#include "UI_view2d.h"
+
+#include "transform.h"
+#include "transform_convert.h"
+
+/** Used for sequencer transform. */
+typedef struct TransDataSeq {
+  struct Sequence *seq;
+  float orig_origin_position[2];
+  float orig_translation[2];
+  float orig_scale[2];
+  float orig_rotation;
+} TransDataSeq;
+
+static TransData *SeqToTransData(const Scene *scene,
+                                 Sequence *seq,
+                                 TransData *td,
+                                 TransData2D *td2d,
+                                 TransDataSeq *tdseq,
+                                 int vert_index)
+{
+  const StripTransform *transform = seq->strip->transform;
+  float origin[2];
+  SEQ_image_transform_origin_offset_pixelspace_get(scene, seq, origin);
+  float vertex[2] = {origin[0], origin[1]};
+
+  /* Add control vertex, so rotation and scale can be calculated. */
+  if (vert_index == 1) {
+    vertex[0] += 1.0f;
+  }
+  else if (vert_index == 2) {
+    vertex[1] += 1.0f;
+  }
+
+  td2d->loc[0] = vertex[0];
+  td2d->loc[1] = vertex[1];
+  td2d->loc2d = NULL;
+  td->loc = td2d->loc;
+  copy_v3_v3(td->iloc, td->loc);
+
+  td->center[0] = origin[0];
+  td->center[1] = origin[1];
+
+  memset(td->axismtx, 0, sizeof(td->axismtx));
+  td->axismtx[2][2] = 1.0f;
+  unit_m3(td->mtx);
+  unit_m3(td->smtx);
+
+  tdseq->seq = seq;
+  copy_v2_v2(tdseq->orig_origin_position, origin);
+  tdseq->orig_translation[0] = transform->xofs;
+  tdseq->orig_translation[1] = transform->yofs;
+  tdseq->orig_scale[0] = transform->scale_x;
+  tdseq->orig_scale[1] = transform->scale_y;
+  tdseq->orig_rotation = transform->rotation;
+
+  td->extra = (void *)tdseq;
+  td->ext = NULL;
+  td->flag |= TD_SELECTED;
+  td->dist = 0.0;
+
+  return td;
+}
+
+static void freeSeqData(TransInfo *UNUSED(t), TransDataContainer *tc, TransCustomData *UNUSED(custom_data))
+{
+  TransData *td = (TransData *)tc->data;
+  MEM_freeN(td->extra);
+}
+
+void createTransSeqImageData(TransInfo *t)
+{
+  Editing *ed = SEQ_editing_get(t->scene);
+  ListBase *seqbase = SEQ_active_seqbase_get(ed);
+  SeqCollection *strips = SEQ_query_rendered_strips(seqbase, t->scene->r.cfra, 0);
+  SEQ_filter_selected_strips(strips);
+
+  const int count = SEQ_collection_len(strips);
+  if (ed == NULL || count == 0) {
+    SEQ_collection_free(strips);
+    return;
+  }
+
+  TransDataContainer *tc = TRANS_DATA_CONTAINER_FIRST_SINGLE(t);
+  tc->custom.type.free_cb = freeSeqData;
+
+  tc->data_len = count * 3; /* 3 vertices per sequence are needed. */
+  TransData *td = tc->data = MEM_callocN(tc->data_len * sizeof(TransData), "TransSeq TransData");
+  TransData2D *td2d = tc->data_2d = MEM_callocN(tc->data_len * sizeof(TransData2D),
+                                                "TransSeq TransData2D");
+  TransDataSeq *tdseq = MEM_callocN(tc->data_len * sizeof(TransDataSeq), "TransSeq TransDataSeq");
+
+  Sequence *seq;
+  SEQ_ITERATOR_FOREACH (seq, strips) {
+    /* One `Sequence` needs 3 `TransData` entries - center point placed in image origin, then 2
+     * points offset by 1 in X and Y direction respectively, so rotation and scale can be
+     * calculated from these points. */
+    SeqToTransData(t->scene, seq, td++, td2d++, tdseq++, 0);
+    SeqToTransData(t->scene, seq, td++, td2d++, tdseq++, 1);
+    SeqToTransData(t->scene, seq, td++, td2d++, tdseq++, 2);
+  }
+
+  SEQ_collection_free(strips);
+}
+
+void recalcData_sequencer_image(TransInfo *t)
+{
+  TransDataContainer *tc = TRANS_DATA_CONTAINER_FIRST_SINGLE(t);
+  TransData *td = NULL;
+  TransData2D *td2d = NULL;
+  int i;
+
+  for (i = 0, td = tc->data, td2d = tc->data_2d; i < tc->data_len; i++, td++, td2d++) {
+    /* Origin. */
+    float loc[2];
+    copy_v2_v2(loc, td2d->loc);
+    i++, td++, td2d++;
+
+    /* X and Y control points used to read scale and rotation. */
+    float handle_x[2];
+    copy_v2_v2(handle_x, td2d->loc);
+    sub_v2_v2(handle_x, loc);
+    i++, td++, td2d++;
+    float handle_y[2];
+    copy_v2_v2(handle_y, td2d->loc);
+    sub_v2_v2(handle_y, loc);
+
+    TransDataSeq *tdseq = td->extra;
+    Sequence *seq = tdseq->seq;
+    StripTransform *transform = seq->strip->transform;
+    float mirror[2];
+    SEQ_image_transform_mirror_factor_get(seq, mirror);
+
+    /* Calculate translation. */
+    float translation[2];
+    copy_v2_v2(translation, tdseq->orig_origin_position);
+    sub_v2_v2(translation, loc);
+    mul_v2_v2(translation, mirror);
+    transform->xofs = tdseq->orig_translation[0] - translation[0];
+    transform->yofs = tdseq->orig_translation[1] - translation[1];
+
+    /* Scale. */
+    transform->scale_x = tdseq->orig_scale[0] * fabs(len_v2(handle_x));
+    transform->scale_y = tdseq->orig_scale[1] * fabs(len_v2(handle_y));
+
+    /* Rotation. Scaling can cause negative rotation. */
+    if (t->mode == TFM_ROTATION) {
+      float rotation = angle_signed_v2v2(handle_x, (float[]){1, 0}) * mirror[0] * mirror[1];
+      transform->rotation = tdseq->orig_rotation + rotation;
+      transform->rotation += DEG2RAD(360.0);
+      transform->rotation = fmod(transform->rotation, DEG2RAD(360.0));
+    }
+    SEQ_relations_invalidate_cache_preprocessed(t->scene, seq);
+  }
+}
diff --git a/source/blender/editors/transform/transform_draw_cursors.c b/source/blender/editors/transform/transform_draw_cursors.c
index ead8eae0997..af1f3cb72a4 100644
--- a/source/blender/editors/transform/transform_draw_cursors.c
+++ b/source/blender/editors/transform/transform_draw_cursors.c
@@ -95,7 +95,7 @@ static void drawArrow(const uint pos_id, const enum eArrowDirection dir)
 bool transform_draw_cursor_poll(bContext *C)
 {
   ARegion *region = CTX_wm_region(C);
-  return (region && region->regiontype == RGN_TYPE_WINDOW) ? 1 : 0;
+  return (region && ELEM(region->regiontype, RGN_TYPE_WINDOW, RGN_TYPE_PREVIEW)) ? 1 : 0;
 }
 
 /**
diff --git a/source/blender/editors/transform/transform_generics.c b/source/blender/editors/transform/transform_generics.c
index c493b9bd102..fa323f0c1f7 100644
--- a/source/blender/editors/transform/transform_generics.c
+++ b/source/blender/editors/transform/transform_generics.c
@@ -59,6 +59,8 @@
 #include "UI_resources.h"
 #include "UI_view2d.h"
 
+#include "SEQ_sequencer.h"
+
 #include "transform.h"
 #include "transform_convert.h"
 #include "transform_mode.h"
@@ -335,6 +337,11 @@ void initTransInfo(bContext *C, TransInfo *t, wmOperator *op, const wmEvent *eve
       t->options |= CTX_MASK;
     }
   }
+  else if (t->spacetype == SPACE_SEQ && region->regiontype == RGN_TYPE_PREVIEW) {
+    t->view = &region->v2d;
+    t->around = SEQ_tool_settings_pivot_point_get(t->scene);
+    t->options |= CTX_SEQUENCER_IMAGE;
+  }
   else {
     if (region) {
       /* XXX: For now, get View2D from the active region. */
diff --git a/source/blender/editors/transform/transform_gizmo_2d.c b/source/blender/editors/transform/transform_gizmo_2d.c
index 0b677e2560b..0d66db0d7e1 100644
--- a/source/blender/editors/transform/transform_gizmo_2d.c
+++ b/source/blender/editors/transform/transform_gizmo_2d.c
@@ -49,6 +49,11 @@
 #include "ED_screen.h"
 #include "ED_uvedit.h"
 
+#include "SEQ_iterator.h"
+#include "SEQ_sequencer.h"
+#include "SEQ_time.h"
+#include "SEQ_transform.h"
+
 #include "transform.h" /* own include */
 
 /* -------------------------------------------------------------------- */
@@ -234,17 +239,66 @@ static bool gizmo2d_calc_bounds(const bContext *C, float *r_center, float *r_min
   return changed;
 }
 
+static float gizmo2d_calc_rotation(const bContext *C)
+{
+  ScrArea *area = CTX_wm_area(C);
+  if (area->spacetype != SPACE_SEQ) {
+    return 0.0f;
+  }
+
+  Scene *scene = CTX_data_scene(C);
+  Editing *ed = SEQ_editing_get(scene);
+  ListBase *seqbase = SEQ_active_seqbase_get(ed);
+  SeqCollection *strips = SEQ_query_rendered_strips(seqbase, scene->r.cfra, 0);
+  SEQ_filter_selected_strips(strips);
+
+  Sequence *seq;
+  SEQ_ITERATOR_FOREACH (seq, strips) {
+    if (seq == ed->act_seq) {
+      StripTransform *transform = seq->strip->transform;
+      float mirror[2];
+      SEQ_image_transform_mirror_factor_get(seq, mirror);
+      SEQ_collection_free(strips);
+      return transform->rotation * mirror[0] * mirror[1];
+    }
+  }
+
+  SEQ_collection_free(strips);
+  return 0.0f;
+}
+
 static bool gizmo2d_calc_center(const bContext *C, float r_center[2])
 {
   ScrArea *area = CTX_wm_area(C);
+  Scene *scene = CTX_data_scene(C);
   bool has_select = false;
   zero_v2(r_center);
   if (area->spacetype == SPACE_IMAGE) {
     SpaceImage *sima = area->spacedata.first;
-    Scene *scene = CTX_data_scene(C);
     ViewLayer *view_layer = CTX_data_view_layer(C);
     ED_uvedit_center_from_pivot_ex(sima, scene, view_layer, r_center, sima->around, &has_select);
   }
+  else if (area->spacetype == SPACE_SEQ) {
+    ListBase *seqbase = SEQ_active_seqbase_get(SEQ_editing_get(scene));
+    SeqCollection *strips = SEQ_query_rendered_strips(seqbase, scene->r.cfra, 0);
+    SEQ_filter_selected_strips(strips);
+
+    if (SEQ_collection_len(strips) <= 0) {
+      SEQ_collection_free(strips);
+      return false;
+    }
+
+    has_select = true;
+    Sequence *seq;
+    SEQ_ITERATOR_FOREACH (seq, strips) {
+      float origin[2];
+      SEQ_image_transform_origin_offset_pixelspace_get(scene, seq, origin);
+      add_v2_v2(r_center, origin);
+    }
+    mul_v2_fl(r_center, 1.0f / SEQ_collection_len(strips));
+
+    SEQ_collection_free(strips);
+  }
   return has_select;
 }
 
@@ -338,7 +392,7 @@ static void gizmo2d_xform_setup(const bContext *UNUSED(C), wmGizmoGroup *gzgroup
       }
     }
 
-    RNA_boolean_set(ptr, "release_confirm", 1);
+    RNA_boolean_set(ptr, "release_confirm", true);
   }
 
   {
@@ -539,6 +593,7 @@ void ED_widgetgroup_gizmo2d_xform_no_cage_callbacks_set(wmGizmoGroupType *gzgt)
 typedef struct GizmoGroup_Resize2D {
   wmGizmo *gizmo_xy[3];
   float origin[2];
+  float rotation;
 } GizmoGroup_Resize2D;
 
 static GizmoGroup_Resize2D *gizmogroup2d_resize_init(wmGizmoGroup *gzgroup)
@@ -571,6 +626,7 @@ static void gizmo2d_resize_refresh(const bContext *C, wmGizmoGroup *gzgroup)
       ggd->gizmo_xy[i]->flag &= ~WM_GIZMO_HIDDEN;
     }
     copy_v2_v2(ggd->origin, origin);
+    ggd->rotation = gizmo2d_calc_rotation(C);
   }
 }
 
@@ -595,6 +651,13 @@ static void gizmo2d_resize_draw_prepare(const bContext *C, wmGizmoGroup *gzgroup
   for (int i = 0; i < ARRAY_SIZE(ggd->gizmo_xy); i++) {
     wmGizmo *gz = ggd->gizmo_xy[i];
     WM_gizmo_set_matrix_location(gz, origin);
+
+    if (i < 2) {
+      float axis[3] = {0.0f}, rotated_axis[3];
+      axis[i] = 1.0f;
+      rotate_v3_v3v3fl(rotated_axis, axis, (float[3]){0, 0, 1}, ggd->rotation);
+      WM_gizmo_set_matrix_rotation_from_z_axis(gz, rotated_axis);
+    }
   }
 }
 
@@ -617,10 +680,6 @@ static void gizmo2d_resize_setup(const bContext *UNUSED(C), wmGizmoGroup *gzgrou
 
       /* set up widget data */
       RNA_float_set(gz->ptr, "length", 1.0f);
-      float axis[3] = {0.0f};
-      axis[i] = 1.0f;
-      WM_gizmo_set_matrix_rotation_from_z_axis(gz, axis);
-
       RNA_enum_set(gz->ptr, "draw_style", ED_GIZMO_ARROW_STYLE_BOX);
 
       WM_gizmo_set_line_width(gz, GIZMO_AXIS_LINE_WIDTH);
diff --git a/source/blender/editors/transform/transform_mode.c b/source/blender/editors/transform/transform_mode.c
index b9fb8a86752..b14d499cb66 100644
--- a/source/blender/editors/transform/transform_mode.c
+++ b/source/blender/editors/transform/transform_mode.c
@@ -75,7 +75,7 @@ bool transdata_check_local_center(const TransInfo *t, short around)
            /* implicit: (t->flag & T_EDIT) */
            (ELEM(t->obedit_type, OB_MESH, OB_CURVE, OB_MBALL, OB_ARMATURE, OB_GPENCIL)) ||
            (t->spacetype == SPACE_GRAPH) ||
-           (t->options & (CTX_MOVIECLIP | CTX_MASK | CTX_PAINT_CURVE))));
+           (t->options & (CTX_MOVIECLIP | CTX_MASK | CTX_PAINT_CURVE | CTX_SEQUENCER_IMAGE))));
 }
 
 /* Informs if the mode can be switched during modal. */
diff --git a/source/blender/editors/transform/transform_snap_sequencer.c b/source/blender/editors/transform/transform_snap_sequencer.c
index e82a00bcc77..2acdf5cfd9c 100644
--- a/source/blender/editors/transform/transform_snap_sequencer.c
+++ b/source/blender/editors/transform/transform_snap_sequencer.c
@@ -254,6 +254,10 @@ static int seq_snap_threshold_get_frame_distance(const TransInfo *t)
 
 TransSeqSnapData *transform_snap_sequencer_data_alloc(const TransInfo *t)
 {
+  if (t->data_type == TC_SEQ_IMAGE_DATA) {
+    return NULL;
+  }
+
   TransSeqSnapData *snap_data = MEM_callocN(sizeof(TransSeqSnapData), __func__);
   ListBase *seqbase = SEQ_active_seqbase_get(SEQ_editing_get(t->scene));