Fix #141282: VSE cache issues when rendering at reduced resolution scale

If render settings resolution scale had lowered resolution, cached
images from render image/animation session could "stay around"
and be incorrectly used in the VSE preview area. Two cases I found are
fixed here:
- Intra-frame cache was not flushed upon actual final resolution
  change,
- "Source images" for effect/scene strips were not removed when
  requested resolution no longer matches their rendered resolution.

Pull Request: https://projects.blender.org/blender/blender/pulls/141297

source/blender/sequencer/intern/cache/intra_frame_cache.cc

@@ -30,6 +30,8 @@ struct IntraFrameCache {
   StripImageMap composite;
   float timeline_frame = -1.0f;
   int view_id = -1;
+  int width = -1;
+  int height = -1;
 
   ~IntraFrameCache()
   {
@@ -54,6 +56,8 @@ void intra_frame_cache_invalidate(Scene *scene)
     cache->composite.clear();
     cache->timeline_frame = -1.0f;
     cache->view_id = -1;
+    cache->width = -1;
+    cache->height = -1;
   }
 }
 
@@ -162,13 +166,17 @@ void intra_frame_cache_destroy(Scene *scene)
   }
 }
 
-void intra_frame_cache_set_cur_frame(Scene *scene, float frame, int view_id)
+void intra_frame_cache_set_cur_frame(Scene *scene, float frame, int view_id, int width, int height)
 {
   IntraFrameCache *cache = query_intra_frame_cache(scene);
   if (cache != nullptr) {
-    if (cache->timeline_frame != frame || cache->view_id != view_id) {
+    if (cache->timeline_frame != frame || cache->view_id != view_id || cache->width != width ||
+        cache->height != height)
+    {
       cache->timeline_frame = frame;
       cache->view_id = view_id;
+      cache->width = width;
+      cache->height = height;
       cache->preprocessed.clear();
       cache->composite.clear();
     }

source/blender/sequencer/intern/cache/intra_frame_cache.hh

@@ -35,6 +35,7 @@ void intra_frame_cache_destroy(Scene *scene);
 void intra_frame_cache_invalidate(Scene *scene, const Strip *strip);
 void intra_frame_cache_invalidate(Scene *scene);
 
-void intra_frame_cache_set_cur_frame(Scene *scene, float frame, int view_id);
+void intra_frame_cache_set_cur_frame(
+    Scene *scene, float frame, int view_id, int width, int height);
 
 }  // namespace blender::seq

source/blender/sequencer/intern/cache/source_image_cache.cc

@@ -122,6 +122,17 @@ ImBuf *source_image_cache_get(const RenderData *context, const Strip *strip, flo
     if (frame != nullptr) {
       res = frame->image;
     }
+
+    /* For effect and scene strips, check if the cached result matches our current
+     * render resolution. If it does not, remove stale source entries for this strip. */
+    if (res != nullptr &&
+        ((strip->type & STRIP_TYPE_EFFECT) != 0 || strip->type == STRIP_TYPE_SCENE))
+    {
+      if (res->x != context->rectx || res->y != context->recty) {
+        cache->remove_entry(strip);
+        return nullptr;
+      }
+    }
   }
 
   if (res) {

source/blender/sequencer/intern/render.cc

@@ -1629,7 +1629,8 @@ static ImBuf *do_render_strip_seqbase(const RenderData *context,
       BKE_animsys_evaluate_all_animation(context->bmain, context->depsgraph, frame_index);
     }
 
-    intra_frame_cache_set_cur_frame(context->scene, frame_index, context->view_id);
+    intra_frame_cache_set_cur_frame(
+        context->scene, frame_index, context->view_id, context->rectx, context->recty);
     ibuf = seq_render_strip_stack(context,
                                   state,
                                   channels,
@@ -2019,7 +2020,8 @@ ImBuf *render_give_ibuf(const RenderData *context, float timeline_frame, int cha
     channels = ed->displayed_channels;
   }
 
-  intra_frame_cache_set_cur_frame(scene, timeline_frame, context->view_id);
+  intra_frame_cache_set_cur_frame(
+      scene, timeline_frame, context->view_id, context->rectx, context->recty);
 
   Scene *orig_scene = prefetch_get_original_scene(context);
   ImBuf *out = nullptr;