GPencil: New modules for Import and Export

This patch adds support to export and import grease pencil in several formats.

Inlude:

* Export SVG
* Export PDF (always from camera view)

* Import SVG

The import and export only support solid colors and not gradients or textures.

Requires libharu and pugixml.

For importing SVG, the NanoSVG lib is used, but this does not require installation (just a .h file embedded in the project  folder)

Example of PDF export: https://youtu.be/BMm0KeMJsI4

Reviewed By: #grease_pencil, HooglyBoogly

Maniphest Tasks: T83190, T79875, T83191, T83192

Differential Revision: https://developer.blender.org/D10482

1 files changed, 202 insertions, 0 deletions

diff --git a/source/blender/io/gpencil/intern/gpencil_io_capi.cc b/source/blender/io/gpencil/intern/gpencil_io_capi.cc
new file mode 100644
index 00000000000..34539a66fe8
--- /dev/null
+++ b/source/blender/io/gpencil/intern/gpencil_io_capi.cc
@@ -0,0 +1,202 @@
+/*
+ * 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) 2020 Blender Foundation
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup bgpencil
+ */
+
+#include <stdio.h>
+
+#include "BLI_listbase.h"
+
+#include "DNA_gpencil_types.h"
+#include "DNA_screen_types.h"
+#include "DNA_space_types.h"
+
+#include "BKE_context.h"
+#include "BKE_gpencil.h"
+#include "BKE_main.h"
+#include "BKE_scene.h"
+
+#include "DEG_depsgraph.h"
+#include "DEG_depsgraph_query.h"
+
+#include "../gpencil_io.h"
+
+#ifdef WITH_HARU
+#  include "gpencil_io_export_pdf.h"
+#endif
+
+#ifdef WITH_PUGIXML
+#  include "gpencil_io_export_svg.h"
+#endif
+
+#include "gpencil_io_import_svg.h"
+
+#ifdef WITH_HARU
+using blender::io::gpencil::GpencilExporterPDF;
+#endif
+#ifdef WITH_PUGIXML
+using blender::io::gpencil::GpencilExporterSVG;
+#endif
+using blender::io::gpencil::GpencilImporterSVG;
+
+/* Check if frame is included. */
+static bool is_keyframe_included(bGPdata *gpd_, const int32_t framenum, const bool use_selected)
+{
+  /* Check if exist a frame. */
+  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd_->layers) {
+    if (gpl->flag & GP_LAYER_HIDE) {
+      continue;
+    }
+    LISTBASE_FOREACH (bGPDframe *, gpf, &gpl->frames) {
+      if (gpf->framenum == framenum) {
+        if ((!use_selected) || (use_selected && (gpf->flag & GP_FRAME_SELECT))) {
+          return true;
+        }
+      }
+    }
+  }
+  return false;
+}
+
+/* Import frame. */
+static bool gpencil_io_import_frame(void *in_importer, const GpencilIOParams &iparams)
+{
+
+  bool result = false;
+  switch (iparams.mode) {
+    case GP_IMPORT_FROM_SVG: {
+      GpencilImporterSVG *importer = (GpencilImporterSVG *)in_importer;
+      result |= importer->read();
+      break;
+    }
+    /* Add new import formats here. */
+    default:
+      break;
+  }
+
+  return result;
+}
+
+/* Export frame in PDF. */
+#ifdef WITH_HARU
+static bool gpencil_io_export_pdf(Depsgraph *depsgraph,
+                                  Scene *scene,
+                                  Object *ob,
+                                  GpencilExporterPDF *exporter,
+                                  const GpencilIOParams *iparams)
+{
+  bool result = false;
+  Object *ob_eval_ = (Object *)DEG_get_evaluated_id(depsgraph, &ob->id);
+  bGPdata *gpd_eval = (bGPdata *)ob_eval_->data;
+
+  exporter->frame_number_set(iparams->frame_cur);
+  result |= exporter->new_document();
+
+  const bool use_frame_selected = (iparams->frame_mode == GP_EXPORT_FRAME_SELECTED);
+  if (use_frame_selected) {
+    for (int32_t i = iparams->frame_start; i < iparams->frame_end + 1; i++) {
+      if (!is_keyframe_included(gpd_eval, i, use_frame_selected)) {
+        continue;
+      }
+
+      CFRA = i;
+      BKE_scene_graph_update_for_newframe(depsgraph);
+      exporter->frame_number_set(i);
+      exporter->add_newpage();
+      exporter->add_body();
+    }
+    result = exporter->write();
+    /* Back to original frame. */
+    exporter->frame_number_set(iparams->frame_cur);
+    CFRA = iparams->frame_cur;
+    BKE_scene_graph_update_for_newframe(depsgraph);
+  }
+  else {
+    exporter->add_newpage();
+    exporter->add_body();
+    result = exporter->write();
+  }
+
+  return result;
+}
+#endif
+
+/* Export current frame in SVG. */
+#ifdef WITH_PUGIXML
+static bool gpencil_io_export_frame_svg(GpencilExporterSVG *exporter,
+                                        const GpencilIOParams *iparams,
+                                        const bool newpage,
+                                        const bool body,
+                                        const bool savepage)
+{
+  bool result = false;
+  exporter->frame_number_set(iparams->frame_cur);
+  if (newpage) {
+    result |= exporter->add_newpage();
+  }
+  if (body) {
+    result |= exporter->add_body();
+  }
+  if (savepage) {
+    result = exporter->write();
+  }
+  return result;
+}
+#endif
+
+/* Main import entry point function. */
+bool gpencil_io_import(const char *filename, GpencilIOParams *iparams)
+{
+  GpencilImporterSVG importer = GpencilImporterSVG(filename, iparams);
+
+  return gpencil_io_import_frame(&importer, *iparams);
+}
+
+/* Main export entry point function. */
+bool gpencil_io_export(const char *filename, GpencilIOParams *iparams)
+{
+  Depsgraph *depsgraph_ = CTX_data_depsgraph_pointer(iparams->C);
+  Scene *scene_ = CTX_data_scene(iparams->C);
+  Object *ob = CTX_data_active_object(iparams->C);
+
+  UNUSED_VARS(depsgraph_, scene_, ob);
+
+  switch (iparams->mode) {
+#ifdef WITH_PUGIXML
+    case GP_EXPORT_TO_SVG: {
+      GpencilExporterSVG exporter = GpencilExporterSVG(filename, iparams);
+      return gpencil_io_export_frame_svg(&exporter, iparams, true, true, true);
+      break;
+    }
+#endif
+#ifdef WITH_HARU
+    case GP_EXPORT_TO_PDF: {
+      GpencilExporterPDF exporter = GpencilExporterPDF(filename, iparams);
+      return gpencil_io_export_pdf(depsgraph_, scene_, ob, &exporter, iparams);
+      break;
+    }
+#endif
+    /* Add new export formats here. */
+    default:
+      break;
+  }
+  return false;
+}