GPencil: New option to Merge All layers in active one

This new option allows to combine all layers in the active one. Also the merge down option has been improved.

Reviewed By: mendio, pablo vazquez (UI)

Differential Revision: https://developer.blender.org/D13054

1 files changed, 68 insertions, 0 deletions

diff --git a/source/blender/editors/gpencil/gpencil_utils.c b/source/blender/editors/gpencil/gpencil_utils.c
index c4319fd7ee2..f3c3aa10632 100644
--- a/source/blender/editors/gpencil/gpencil_utils.c
+++ b/source/blender/editors/gpencil/gpencil_utils.c
@@ -3415,3 +3415,71 @@ void ED_gpencil_stroke_close_by_distance(bGPDstroke *gps, const float threshold)
     BKE_gpencil_stroke_close(gps);
   }
 }
+
+/* Merge two layers. */
+void ED_gpencil_layer_merge(bGPdata *gpd,
+                            bGPDlayer *gpl_src,
+                            bGPDlayer *gpl_dst,
+                            const bool reverse)
+{
+  /* Collect frames of gpl_dst in hash table to avoid O(n^2) lookups. */
+  GHash *gh_frames_dst = BLI_ghash_int_new_ex(__func__, 64);
+  LISTBASE_FOREACH (bGPDframe *, gpf_dst, &gpl_dst->frames) {
+    BLI_ghash_insert(gh_frames_dst, POINTER_FROM_INT(gpf_dst->framenum), gpf_dst);
+  }
+
+  /* Read all frames from merge layer and add any missing in destination layer,
+   * copying all previous strokes to keep the image equals.
+   * Need to do it in a separated loop to avoid strokes accumulation. */
+  LISTBASE_FOREACH (bGPDframe *, gpf_src, &gpl_src->frames) {
+    /* Try to find frame in destination layer hash table. */
+    bGPDframe *gpf_dst = BLI_ghash_lookup(gh_frames_dst, POINTER_FROM_INT(gpf_src->framenum));
+    if (!gpf_dst) {
+      gpf_dst = BKE_gpencil_layer_frame_get(gpl_dst, gpf_src->framenum, GP_GETFRAME_ADD_COPY);
+      /* Use same frame type. */
+      gpf_dst->key_type = gpf_src->key_type;
+      BLI_ghash_insert(gh_frames_dst, POINTER_FROM_INT(gpf_src->framenum), gpf_dst);
+    }
+  }
+
+  /* Read all frames from merge layer and add strokes. */
+  LISTBASE_FOREACH (bGPDframe *, gpf_src, &gpl_src->frames) {
+    /* Try to find frame in destination layer hash table. */
+    bGPDframe *gpf_dst = BLI_ghash_lookup(gh_frames_dst, POINTER_FROM_INT(gpf_src->framenum));
+    /* Add to tail all strokes. */
+    if (gpf_dst) {
+      if (reverse) {
+        BLI_movelisttolist_reverse(&gpf_dst->strokes, &gpf_src->strokes);
+      }
+      else {
+        BLI_movelisttolist(&gpf_dst->strokes, &gpf_src->strokes);
+      }
+    }
+  }
+
+  /* Add Masks to destination layer. */
+  LISTBASE_FOREACH (bGPDlayer_Mask *, mask, &gpl_src->mask_layers) {
+    /* Don't add merged layers or missing layer names. */
+    if (!BKE_gpencil_layer_named_get(gpd, mask->name) || STREQ(mask->name, gpl_src->info) ||
+        STREQ(mask->name, gpl_dst->info)) {
+      continue;
+    }
+    if (!BKE_gpencil_layer_mask_named_get(gpl_dst, mask->name)) {
+      bGPDlayer_Mask *mask_new = MEM_dupallocN(mask);
+      BLI_addtail(&gpl_dst->mask_layers, mask_new);
+      gpl_dst->act_mask++;
+    }
+  }
+
+  /* Set destination layer as active. */
+  BKE_gpencil_layer_active_set(gpd, gpl_dst);
+
+  /* Now delete merged layer. */
+  BKE_gpencil_layer_delete(gpd, gpl_src);
+  BLI_ghash_free(gh_frames_dst, NULL, NULL);
+
+  /* Reorder masking. */
+  if (gpl_dst->mask_layers.first) {
+    BKE_gpencil_layer_mask_sort(gpd, gpl_dst);
+  }
+}