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, 386 insertions, 0 deletions

diff --git a/source/blender/io/gpencil/intern/gpencil_io_base.cc b/source/blender/io/gpencil/intern/gpencil_io_base.cc
new file mode 100644
index 00000000000..855252e648c
--- /dev/null
+++ b/source/blender/io/gpencil/intern/gpencil_io_base.cc
@@ -0,0 +1,386 @@
+
+
+/*
+ * 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 "BLI_float2.hh"
+#include "BLI_float3.hh"
+#include "BLI_float4x4.hh"
+#include "BLI_path_util.h"
+#include "BLI_span.hh"
+
+#include "DNA_gpencil_types.h"
+#include "DNA_layer_types.h"
+#include "DNA_material_types.h"
+#include "DNA_scene_types.h"
+#include "DNA_screen_types.h"
+
+#include "BKE_camera.h"
+#include "BKE_context.h"
+#include "BKE_gpencil.h"
+#include "BKE_gpencil_geom.h"
+#include "BKE_main.h"
+#include "BKE_material.h"
+
+#include "UI_view2d.h"
+
+#include "ED_view3d.h"
+
+#include "DEG_depsgraph.h"
+#include "DEG_depsgraph_query.h"
+
+#include "gpencil_io_base.h"
+
+using blender::Span;
+
+namespace blender::io::gpencil {
+
+/* Constructor. */
+GpencilIO::GpencilIO(const GpencilIOParams *iparams)
+{
+  params_ = *iparams;
+
+  /* Easy access data. */
+  bmain_ = CTX_data_main(params_.C);
+  depsgraph_ = CTX_data_depsgraph_pointer(params_.C);
+  scene_ = CTX_data_scene(params_.C);
+  rv3d_ = (RegionView3D *)params_.region->regiondata;
+  gpd_ = (params_.ob != nullptr) ? (bGPdata *)params_.ob->data : nullptr;
+  cfra_ = iparams->frame_cur;
+
+  /* Calculate camera matrix. */
+  Object *cam_ob = params_.v3d->camera;
+  if (cam_ob != nullptr) {
+    /* Set up parameters. */
+    CameraParams params;
+    BKE_camera_params_init(&params);
+    BKE_camera_params_from_object(&params, cam_ob);
+
+    /* Compute matrix, viewplane, .. */
+    RenderData *rd = &scene_->r;
+    BKE_camera_params_compute_viewplane(&params, rd->xsch, rd->ysch, rd->xasp, rd->yasp);
+    BKE_camera_params_compute_matrix(&params);
+
+    float viewmat[4][4];
+    invert_m4_m4(viewmat, cam_ob->obmat);
+
+    mul_m4_m4m4(persmat_, params.winmat, viewmat);
+  }
+  else {
+    unit_m4(persmat_);
+  }
+
+  winx_ = params_.region->winx;
+  winy_ = params_.region->winy;
+
+  /* Camera rectangle. */
+  if (rv3d_->persp == RV3D_CAMOB) {
+    render_x_ = (scene_->r.xsch * scene_->r.size) / 100;
+    render_y_ = (scene_->r.ysch * scene_->r.size) / 100;
+
+    ED_view3d_calc_camera_border(CTX_data_scene(params_.C),
+                                 depsgraph_,
+                                 params_.region,
+                                 params_.v3d,
+                                 rv3d_,
+                                 &camera_rect_,
+                                 true);
+    is_camera_ = true;
+    camera_ratio_ = render_x_ / (camera_rect_.xmax - camera_rect_.xmin);
+    offset_.x = camera_rect_.xmin;
+    offset_.y = camera_rect_.ymin;
+  }
+  else {
+    is_camera_ = false;
+    /* Calc selected object boundbox. Need set initial value to some variables. */
+    camera_ratio_ = 1.0f;
+    offset_.x = 0.0f;
+    offset_.y = 0.0f;
+
+    selected_objects_boundbox_calc();
+    rctf boundbox;
+    selected_objects_boundbox_get(&boundbox);
+
+    render_x_ = boundbox.xmax - boundbox.xmin;
+    render_y_ = boundbox.ymax - boundbox.ymin;
+    offset_.x = boundbox.xmin;
+    offset_.y = boundbox.ymin;
+  }
+}
+
+/** Create a list of selected objects sorted from back to front */
+void GpencilIO::create_object_list()
+{
+  ViewLayer *view_layer = CTX_data_view_layer(params_.C);
+
+  float3 camera_z_axis;
+  copy_v3_v3(camera_z_axis, rv3d_->viewinv[2]);
+  ob_list_.clear();
+
+  LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+    Object *object = base->object;
+
+    if (object->type != OB_GPENCIL) {
+      continue;
+    }
+    if ((params_.select_mode == GP_EXPORT_ACTIVE) && (params_.ob != object)) {
+      continue;
+    }
+
+    if ((params_.select_mode == GP_EXPORT_SELECTED) && ((base->flag & BASE_SELECTED) == 0)) {
+      continue;
+    }
+
+    /* Save z-depth from view to sort from back to front. */
+    if (is_camera_) {
+      float camera_z = dot_v3v3(camera_z_axis, object->obmat[3]);
+      ObjectZ obz = {camera_z, object};
+      ob_list_.append(obz);
+    }
+    else {
+      float zdepth = 0;
+      if (rv3d_) {
+        if (rv3d_->is_persp) {
+          zdepth = ED_view3d_calc_zfac(rv3d_, object->obmat[3], nullptr);
+        }
+        else {
+          zdepth = -dot_v3v3(rv3d_->viewinv[2], object->obmat[3]);
+        }
+        ObjectZ obz = {zdepth * -1.0f, object};
+        ob_list_.append(obz);
+      }
+    }
+  }
+  /* Sort list of objects from point of view. */
+  std::sort(ob_list_.begin(), ob_list_.end(), [](const ObjectZ &obz1, const ObjectZ &obz2) {
+    return obz1.zdepth < obz2.zdepth;
+  });
+}
+
+/**
+ * Set file input_text full path.
+ * \param filename: Path of the file provided by save dialog.
+ */
+void GpencilIO::filename_set(const char *filename)
+{
+  BLI_strncpy(filename_, filename, FILE_MAX);
+  BLI_path_abs(filename_, BKE_main_blendfile_path(bmain_));
+}
+
+/** Convert to screenspace. */
+bool GpencilIO::gpencil_3D_point_to_screen_space(const float3 co, float2 &r_co)
+{
+  float3 parent_co = diff_mat_ * co;
+  float2 screen_co;
+  eV3DProjTest test = (eV3DProjTest)(V3D_PROJ_RET_OK);
+  if (ED_view3d_project_float_global(params_.region, parent_co, screen_co, test) ==
+      V3D_PROJ_RET_OK) {
+    if (!ELEM(V2D_IS_CLIPPED, screen_co[0], screen_co[1])) {
+      copy_v2_v2(r_co, screen_co);
+      /* Invert X axis. */
+      if (invert_axis_[0]) {
+        r_co[0] = winx_ - r_co[0];
+      }
+      /* Invert Y axis. */
+      if (invert_axis_[1]) {
+        r_co[1] = winy_ - r_co[1];
+      }
+      /* Apply offset and scale. */
+      sub_v2_v2(r_co, &offset_.x);
+      mul_v2_fl(r_co, camera_ratio_);
+
+      return true;
+    }
+  }
+  r_co[0] = V2D_IS_CLIPPED;
+  r_co[1] = V2D_IS_CLIPPED;
+
+  /* Invert X axis. */
+  if (invert_axis_[0]) {
+    r_co[0] = winx_ - r_co[0];
+  }
+  /* Invert Y axis. */
+  if (invert_axis_[1]) {
+    r_co[1] = winy_ - r_co[1];
+  }
+
+  return false;
+}
+
+/** Convert to render space. */
+float2 GpencilIO::gpencil_3D_point_to_render_space(const float3 co)
+{
+  float3 parent_co = diff_mat_ * co;
+  mul_m4_v3(persmat_, parent_co);
+
+  parent_co.x = parent_co.x / max_ff(FLT_MIN, parent_co[2]);
+  parent_co.y = parent_co.y / max_ff(FLT_MIN, parent_co[2]);
+
+  float2 r_co;
+  r_co.x = (parent_co.x + 1.0f) / 2.0f * (float)render_x_;
+  r_co.y = (parent_co.y + 1.0f) / 2.0f * (float)render_y_;
+
+  /* Invert X axis. */
+  if (invert_axis_[0]) {
+    r_co.x = (float)render_x_ - r_co.x;
+  }
+  /* Invert Y axis. */
+  if (invert_axis_[1]) {
+    r_co.y = (float)render_y_ - r_co.y;
+  }
+
+  return r_co;
+}
+
+/** Convert to 2D. */
+float2 GpencilIO::gpencil_3D_point_to_2D(const float3 co)
+{
+  const bool is_camera = (bool)(rv3d_->persp == RV3D_CAMOB);
+  if (is_camera) {
+    return gpencil_3D_point_to_render_space(co);
+  }
+  float2 result;
+  gpencil_3D_point_to_screen_space(co, result);
+  return result;
+}
+
+/** Get radius of point. */
+float GpencilIO::stroke_point_radius_get(bGPDlayer *gpl, bGPDstroke *gps)
+{
+  bGPDspoint *pt = &gps->points[0];
+  const float2 screen_co = gpencil_3D_point_to_2D(&pt->x);
+
+  /* Radius. */
+  bGPDstroke *gps_perimeter = BKE_gpencil_stroke_perimeter_from_view(
+      rv3d_, gpd_, gpl, gps, 3, diff_mat_.values);
+
+  pt = &gps_perimeter->points[0];
+  const float2 screen_ex = gpencil_3D_point_to_2D(&pt->x);
+
+  const float2 v1 = screen_co - screen_ex;
+  float radius = v1.length();
+  BKE_gpencil_free_stroke(gps_perimeter);
+
+  return MAX2(radius, 1.0f);
+}
+
+void GpencilIO::prepare_layer_export_matrix(Object *ob, bGPDlayer *gpl)
+{
+  BKE_gpencil_layer_transform_matrix_get(depsgraph_, ob, gpl, diff_mat_.values);
+  diff_mat_ = diff_mat_ * float4x4(gpl->layer_invmat);
+}
+
+void GpencilIO::prepare_stroke_export_colors(Object *ob, bGPDstroke *gps)
+{
+  MaterialGPencilStyle *gp_style = BKE_gpencil_material_settings(ob, gps->mat_nr + 1);
+
+  /* Stroke color. */
+  copy_v4_v4(stroke_color_, gp_style->stroke_rgba);
+  avg_opacity_ = 0;
+  /* Get average vertex color and apply. */
+  float avg_color[4] = {0.0f, 0.0f, 0.0f, 0.0f};
+  for (const bGPDspoint &pt : Span(gps->points, gps->totpoints)) {
+    add_v4_v4(avg_color, pt.vert_color);
+    avg_opacity_ += pt.strength;
+  }
+
+  mul_v4_v4fl(avg_color, avg_color, 1.0f / (float)gps->totpoints);
+  interp_v3_v3v3(stroke_color_, stroke_color_, avg_color, avg_color[3]);
+  avg_opacity_ /= (float)gps->totpoints;
+
+  /* Fill color. */
+  copy_v4_v4(fill_color_, gp_style->fill_rgba);
+  /* Apply vertex color for fill. */
+  interp_v3_v3v3(fill_color_, fill_color_, gps->vert_color_fill, gps->vert_color_fill[3]);
+}
+
+float GpencilIO::stroke_average_opacity_get()
+{
+  return avg_opacity_;
+}
+
+bool GpencilIO::is_camera_mode()
+{
+  return is_camera_;
+}
+
+/* Calculate selected strokes boundbox. */
+void GpencilIO::selected_objects_boundbox_calc()
+{
+  const float gap = 10.0f;
+
+  float2 min, max;
+  INIT_MINMAX2(min, max);
+
+  for (ObjectZ &obz : ob_list_) {
+    Object *ob = obz.ob;
+    /* Use evaluated version to get strokes with modifiers. */
+    Object *ob_eval = (Object *)DEG_get_evaluated_id(depsgraph_, &ob->id);
+    bGPdata *gpd_eval = (bGPdata *)ob_eval->data;
+
+    LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd_eval->layers) {
+      if (gpl->flag & GP_LAYER_HIDE) {
+        continue;
+      }
+      BKE_gpencil_layer_transform_matrix_get(depsgraph_, ob_eval, gpl, diff_mat_.values);
+
+      bGPDframe *gpf = gpl->actframe;
+      if (gpf == nullptr) {
+        continue;
+      }
+
+      LISTBASE_FOREACH (bGPDstroke *, gps, &gpf->strokes) {
+        if (gps->totpoints == 0) {
+          continue;
+        }
+        for (const bGPDspoint &pt : MutableSpan(gps->points, gps->totpoints)) {
+          const float2 screen_co = gpencil_3D_point_to_2D(&pt.x);
+          minmax_v2v2_v2(min, max, screen_co);
+        }
+      }
+    }
+  }
+  /* Add small gap. */
+  add_v2_fl(min, gap * -1.0f);
+  add_v2_fl(max, gap);
+
+  select_boundbox_.xmin = min[0];
+  select_boundbox_.ymin = min[1];
+  select_boundbox_.xmax = max[0];
+  select_boundbox_.ymax = max[1];
+}
+
+void GpencilIO::selected_objects_boundbox_get(rctf *boundbox)
+{
+  boundbox->xmin = select_boundbox_.xmin;
+  boundbox->xmax = select_boundbox_.xmax;
+  boundbox->ymin = select_boundbox_.ymin;
+  boundbox->ymax = select_boundbox_.ymax;
+}
+
+void GpencilIO::frame_number_set(const int value)
+{
+  cfra_ = value;
+}
+
+}  // namespace blender::io::gpencil