blender-archive/source/blender/editors/space_view3d/view3d_gizmo_ruler.c

/*
 * 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.
 */

/** \file
 * \ingroup spview3d
 */

#include "BLI_listbase.h"
#include "BLI_string.h"
#include "BLI_rect.h"
#include "BLI_math.h"
#include "BLI_utildefines.h"

#include "BLT_translation.h"

#include "BKE_context.h"
#include "BKE_gpencil.h"
#include "BKE_main.h"
#include "BKE_report.h"

#include "BKE_object.h"
#include "BKE_unit.h"
#include "BKE_material.h"

#include "DNA_meshdata_types.h"
#include "DNA_object_types.h"
#include "DNA_gpencil_types.h"
#include "DNA_view3d_types.h"

#include "ED_gizmo_utils.h"
#include "ED_gpencil.h"
#include "ED_screen.h"
#include "ED_transform_snap_object_context.h"
#include "ED_view3d.h"

#include "UI_resources.h"
#include "UI_interface.h"

#include "MEM_guardedalloc.h"

#include "RNA_access.h"

#include "WM_api.h"
#include "WM_types.h"
#include "WM_toolsystem.h"

#include "view3d_intern.h" /* own include */

#include "GPU_immediate.h"
#include "GPU_immediate_util.h"
#include "GPU_select.h"
#include "GPU_state.h"

#include "BLF_api.h"

static const char *view3d_gzgt_ruler_id = "VIEW3D_GGT_ruler";

#define MVAL_MAX_PX_DIST 12.0f

/* -------------------------------------------------------------------- */
/* Ruler Item (we can have many) */

enum {
  /** Use protractor. */
  RULERITEM_USE_ANGLE = (1 << 0),
  /** Protractor vertex is selected (deleting removes it). */
  RULERITEM_USE_ANGLE_ACTIVE = (1 << 1),
};

/* keep smaller then selection, since we may want click elsewhere without selecting a ruler */
#define RULER_PICK_DIST 12.0f
#define RULER_PICK_DIST_SQ (RULER_PICK_DIST * RULER_PICK_DIST)

/* not clicking on a point */
#define PART_LINE 0xff

/* -------------------------------------------------------------------- */
/* Ruler Info (wmGizmoGroup customdata) */

enum {
  RULER_STATE_NORMAL = 0,
  RULER_STATE_DRAG,
};

enum {
  RULER_SNAP_OK = (1 << 0),
};

struct RulerItem;

typedef struct RulerInfo {
  struct RulerItem *item_active;
  int flag;
  int snap_flag;
  int state;

  struct SnapObjectContext *snap_context;

  /* wm state */
  wmWindow *win;
  ScrArea *sa;
  ARegion *ar; /* re-assigned every modal update */

  /* Track changes in state. */
  struct {
    bool do_snap;
    bool do_thickness;
  } drag_state_prev;

} RulerInfo;

/* -------------------------------------------------------------------- */
/* Ruler Item (two or three points) */

typedef struct RulerItem {
  wmGizmo gz;

  /* worldspace coords, middle being optional */
  float co[3][3];

  int flag;
  int raycast_dir; /* RULER_DIRECTION_* */
} RulerItem;

typedef struct RulerInteraction {
  /* selected coord */
  char co_index; /* 0 -> 2 */
  float drag_start_co[3];
} RulerInteraction;

/* -------------------------------------------------------------------- */
/** \name Internal Ruler Utilities
 * \{ */

static RulerItem *ruler_item_add(wmGizmoGroup *gzgroup)
{
  /* could pass this as an arg */
  const wmGizmoType *gzt_ruler = WM_gizmotype_find("VIEW3D_GT_ruler_item", true);
  RulerItem *ruler_item = (RulerItem *)WM_gizmo_new_ptr(gzt_ruler, gzgroup, NULL);
  WM_gizmo_set_flag(&ruler_item->gz, WM_GIZMO_DRAW_MODAL, true);
  return ruler_item;
}

static void ruler_item_remove(bContext *C, wmGizmoGroup *gzgroup, RulerItem *ruler_item)
{
  RulerInfo *ruler_info = gzgroup->customdata;
  if (ruler_info->item_active == ruler_item) {
    ruler_info->item_active = NULL;
  }
  WM_gizmo_unlink(&gzgroup->gizmos, gzgroup->parent_gzmap, &ruler_item->gz, C);
}

static void ruler_item_as_string(
    RulerItem *ruler_item, UnitSettings *unit, char *numstr, size_t numstr_size, int prec)
{
  if (ruler_item->flag & RULERITEM_USE_ANGLE) {
    const float ruler_angle = angle_v3v3v3(
        ruler_item->co[0], ruler_item->co[1], ruler_item->co[2]);

    if (unit->system == USER_UNIT_NONE) {
      BLI_snprintf(numstr, numstr_size, "%.*f°", prec, RAD2DEGF(ruler_angle));
    }
    else {
      bUnit_AsString2(
          numstr, numstr_size, (double)ruler_angle, prec, B_UNIT_ROTATION, unit, false);
    }
  }
  else {
    const float ruler_len = len_v3v3(ruler_item->co[0], ruler_item->co[2]);

    if (unit->system == USER_UNIT_NONE) {
      BLI_snprintf(numstr, numstr_size, "%.*f", prec, ruler_len);
    }
    else {
      bUnit_AsString2(numstr,
                      numstr_size,
                      (double)(ruler_len * unit->scale_length),
                      prec,
                      B_UNIT_LENGTH,
                      unit,
                      false);
    }
  }
}

static bool view3d_ruler_pick(wmGizmoGroup *gzgroup,
                              RulerItem *ruler_item,
                              const float mval[2],
                              int *r_co_index)
{
  RulerInfo *ruler_info = gzgroup->customdata;
  ARegion *ar = ruler_info->ar;
  bool found = false;

  float dist_best = RULER_PICK_DIST_SQ;
  int co_index_best = -1;

  {
    float co_ss[3][2];
    float dist;
    int j;

    /* should these be checked? - ok for now not to */
    for (j = 0; j < 3; j++) {
      ED_view3d_project_float_global(ar, ruler_item->co[j], co_ss[j], V3D_PROJ_TEST_NOP);
    }

    if (ruler_item->flag & RULERITEM_USE_ANGLE) {
      dist = min_ff(dist_squared_to_line_segment_v2(mval, co_ss[0], co_ss[1]),
                    dist_squared_to_line_segment_v2(mval, co_ss[1], co_ss[2]));
      if (dist < dist_best) {
        dist_best = dist;
        found = true;

        {
          const float dist_points[3] = {
              len_squared_v2v2(co_ss[0], mval),
              len_squared_v2v2(co_ss[1], mval),
              len_squared_v2v2(co_ss[2], mval),
          };
          if (min_fff(UNPACK3(dist_points)) < RULER_PICK_DIST_SQ) {
            co_index_best = min_axis_v3(dist_points);
          }
          else {
            co_index_best = -1;
          }
        }
      }
    }
    else {
      dist = dist_squared_to_line_segment_v2(mval, co_ss[0], co_ss[2]);
      if (dist < dist_best) {
        dist_best = dist;
        found = true;

        {
          const float dist_points[2] = {
              len_squared_v2v2(co_ss[0], mval),
              len_squared_v2v2(co_ss[2], mval),
          };
          if (min_ff(UNPACK2(dist_points)) < RULER_PICK_DIST_SQ) {
            co_index_best = (dist_points[0] < dist_points[1]) ? 0 : 2;
          }
          else {
            co_index_best = -1;
          }
        }
      }
    }
  }

  *r_co_index = co_index_best;
  return found;
}

/**
 * Ensure the 'snap_context' is only cached while dragging,
 * needed since the user may toggle modes between tool use.
 */
static void ruler_state_set(bContext *C, RulerInfo *ruler_info, int state)
{
  Main *bmain = CTX_data_main(C);
  if (state == ruler_info->state) {
    return;
  }

  /* always remove */
  if (ruler_info->snap_context) {
    ED_transform_snap_object_context_destroy(ruler_info->snap_context);
    ruler_info->snap_context = NULL;
  }

  if (state == RULER_STATE_NORMAL) {
    /* pass */
  }
  else if (state == RULER_STATE_DRAG) {
    memset(&ruler_info->drag_state_prev, 0x0, sizeof(ruler_info->drag_state_prev));
    ruler_info->snap_context = ED_transform_snap_object_context_create_view3d(
        bmain,
        CTX_data_scene(C),
        CTX_data_ensure_evaluated_depsgraph(C),
        0,
        ruler_info->ar,
        CTX_wm_view3d(C));
  }
  else {
    BLI_assert(0);
  }

  ruler_info->state = state;
}

static void view3d_ruler_item_project(RulerInfo *ruler_info, float r_co[3], const int xy[2])
{
  ED_view3d_win_to_3d_int(ruler_info->sa->spacedata.first, ruler_info->ar, r_co, xy, r_co);
}

/* use for mousemove events */
static bool view3d_ruler_item_mousemove(RulerInfo *ruler_info,
                                        RulerItem *ruler_item,
                                        const int mval[2],
                                        const bool do_thickness,
                                        const bool do_snap)
{
  const float eps_bias = 0.0002f;
  float dist_px = MVAL_MAX_PX_DIST * U.pixelsize; /* snap dist */

  ruler_info->snap_flag &= ~RULER_SNAP_OK;

  if (ruler_item) {
    RulerInteraction *inter = ruler_item->gz.interaction_data;
    float *co = ruler_item->co[inter->co_index];
    /* restore the initial depth */
    copy_v3_v3(co, inter->drag_start_co);
    view3d_ruler_item_project(ruler_info, co, mval);
    if (do_thickness && inter->co_index != 1) {
      // Scene *scene = CTX_data_scene(C);
      // View3D *v3d = ruler_info->sa->spacedata.first;
      const float mval_fl[2] = {UNPACK2(mval)};
      float ray_normal[3];
      float ray_start[3];
      float *co_other;

      co_other = ruler_item->co[inter->co_index == 0 ? 2 : 0];

      if (ED_transform_snap_object_project_view3d(ruler_info->snap_context,
                                                  SCE_SNAP_MODE_FACE,
                                                  &(const struct SnapObjectParams){
                                                      .snap_select = SNAP_ALL,
                                                      .use_object_edit_cage = true,
                                                  },
                                                  mval_fl,
                                                  &dist_px,
                                                  co,
                                                  ray_normal)) {
        negate_v3(ray_normal);
        /* add some bias */
        madd_v3_v3v3fl(ray_start, co, ray_normal, eps_bias);
        ED_transform_snap_object_project_ray(ruler_info->snap_context,
                                             &(const struct SnapObjectParams){
                                                 .snap_select = SNAP_ALL,
                                                 .use_object_edit_cage = true,
                                             },
                                             ray_start,
                                             ray_normal,
                                             NULL,
                                             co_other,
                                             NULL);
      }
    }
    else if (do_snap) {
      const float mval_fl[2] = {UNPACK2(mval)};

      if (ED_transform_snap_object_project_view3d(
              ruler_info->snap_context,
              (SCE_SNAP_MODE_VERTEX | SCE_SNAP_MODE_EDGE | SCE_SNAP_MODE_FACE),
              &(const struct SnapObjectParams){
                  .snap_select = SNAP_ALL,
                  .use_object_edit_cage = true,
                  .use_occlusion_test = true,
              },
              mval_fl,
              &dist_px,
              co,
              NULL)) {
        ruler_info->snap_flag |= RULER_SNAP_OK;
      }
    }
    return true;
  }
  else {
    return false;
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Ruler/Grease Pencil Conversion
 * \{ */

#define RULER_ID "RulerData3D"
static bool view3d_ruler_to_gpencil(bContext *C, wmGizmoGroup *gzgroup)
{
  // RulerInfo *ruler_info = gzgroup->customdata;
  Main *bmain = CTX_data_main(C);
  Scene *scene = CTX_data_scene(C);

  bGPdata *gpd;
  bGPDlayer *gpl;
  bGPDframe *gpf;
  bGPDstroke *gps;
  RulerItem *ruler_item;
  const char *ruler_name = RULER_ID;
  bool changed = false;

  if (scene->gpd == NULL) {
    scene->gpd = BKE_gpencil_data_addnew(bmain, "Annotations");
  }
  gpd = scene->gpd;

  gpl = BLI_findstring(&gpd->layers, ruler_name, offsetof(bGPDlayer, info));
  if (gpl == NULL) {
    gpl = BKE_gpencil_layer_addnew(gpd, ruler_name, false);
    copy_v4_v4(gpl->color, U.gpencil_new_layer_col);
    gpl->thickness = 1;
    gpl->flag |= GP_LAYER_HIDE;
  }

  gpf = BKE_gpencil_layer_getframe(gpl, CFRA, GP_GETFRAME_ADD_NEW);
  BKE_gpencil_free_strokes(gpf);

  for (ruler_item = gzgroup->gizmos.first; ruler_item;
       ruler_item = (RulerItem *)ruler_item->gz.next) {
    bGPDspoint *pt;
    int j;

    /* allocate memory for a new stroke */
    gps = MEM_callocN(sizeof(bGPDstroke), "gp_stroke");
    if (ruler_item->flag & RULERITEM_USE_ANGLE) {
      gps->totpoints = 3;
      pt = gps->points = MEM_callocN(sizeof(bGPDspoint) * gps->totpoints, "gp_stroke_points");
      for (j = 0; j < 3; j++) {
        copy_v3_v3(&pt->x, ruler_item->co[j]);
        pt->pressure = 1.0f;
        pt->strength = 1.0f;
        pt++;
      }
    }
    else {
      gps->totpoints = 2;
      pt = gps->points = MEM_callocN(sizeof(bGPDspoint) * gps->totpoints, "gp_stroke_points");
      for (j = 0; j < 3; j += 2) {
        copy_v3_v3(&pt->x, ruler_item->co[j]);
        pt->pressure = 1.0f;
        pt->strength = 1.0f;
        pt++;
      }
    }
    gps->flag = GP_STROKE_3DSPACE;
    gps->thickness = 3;
    gps->gradient_f = 1.0f;
    gps->gradient_s[0] = 1.0f;
    gps->gradient_s[1] = 1.0f;

    BLI_addtail(&gpf->strokes, gps);
    changed = true;
  }

  return changed;
}

static bool view3d_ruler_from_gpencil(const bContext *C, wmGizmoGroup *gzgroup)
{
  Scene *scene = CTX_data_scene(C);
  bool changed = false;

  if (scene->gpd) {
    bGPDlayer *gpl;
    const char *ruler_name = RULER_ID;
    gpl = BLI_findstring(&scene->gpd->layers, ruler_name, offsetof(bGPDlayer, info));
    if (gpl) {
      bGPDframe *gpf;
      gpf = BKE_gpencil_layer_getframe(gpl, CFRA, GP_GETFRAME_USE_PREV);
      if (gpf) {
        bGPDstroke *gps;
        for (gps = gpf->strokes.first; gps; gps = gps->next) {
          bGPDspoint *pt = gps->points;
          int j;
          RulerItem *ruler_item = NULL;
          if (gps->totpoints == 3) {
            ruler_item = ruler_item_add(gzgroup);
            for (j = 0; j < 3; j++) {
              copy_v3_v3(ruler_item->co[j], &pt->x);
              pt++;
            }
            ruler_item->flag |= RULERITEM_USE_ANGLE;
            changed = true;
          }
          else if (gps->totpoints == 2) {
            ruler_item = ruler_item_add(gzgroup);
            for (j = 0; j < 3; j += 2) {
              copy_v3_v3(ruler_item->co[j], &pt->x);
              pt++;
            }
            changed = true;
          }
        }
      }
    }
  }

  return changed;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Ruler Item Gizmo Type
 * \{ */

static void gizmo_ruler_draw(const bContext *C, wmGizmo *gz)
{
  Scene *scene = CTX_data_scene(C);
  UnitSettings *unit = &scene->unit;
  RulerInfo *ruler_info = gz->parent_gzgroup->customdata;
  RulerItem *ruler_item = (RulerItem *)gz;
  ARegion *ar = ruler_info->ar;
  RegionView3D *rv3d = ar->regiondata;
  const float cap_size = 4.0f;
  const float bg_margin = 4.0f * U.pixelsize;
  const float arc_size = 64.0f * U.pixelsize;
#define ARC_STEPS 24
  const int arc_steps = ARC_STEPS;
  const float color_act[4] = {1.0f, 1.0f, 1.0f, 1.0f};
  const float color_base[4] = {0.0f, 0.0f, 0.0f, 1.0f};
  uchar color_text[3];
  uchar color_wire[3];
  float color_back[4] = {1.0f, 1.0f, 1.0f, 0.5f};

  /* anti-aliased lines for more consistent appearance */
  GPU_line_smooth(true);
  GPU_line_width(1.0f);

  BLF_enable(blf_mono_font, BLF_ROTATION);
  BLF_size(blf_mono_font, 14 * U.pixelsize, U.dpi);
  BLF_rotation(blf_mono_font, 0.0f);

  UI_GetThemeColor3ubv(TH_TEXT, color_text);
  UI_GetThemeColor3ubv(TH_WIRE, color_wire);

  /* Avoid white on white text. (TODO Fix by using theme) */
  if ((int)color_text[0] + (int)color_text[1] + (int)color_text[2] > 127 * 3 * 0.6f) {
    copy_v3_fl(color_back, 0.0f);
  }

  const bool is_act = (ruler_info->item_active == ruler_item);
  float dir_ruler[2];
  float co_ss[3][2];
  int j;

  /* should these be checked? - ok for now not to */
  for (j = 0; j < 3; j++) {
    ED_view3d_project_float_global(ar, ruler_item->co[j], co_ss[j], V3D_PROJ_TEST_NOP);
  }

  GPU_blend(true);

  const uint shdr_pos = GPU_vertformat_attr_add(
      immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);

  if (ruler_item->flag & RULERITEM_USE_ANGLE) {
    immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_UNIFORM_COLOR);

    float viewport_size[4];
    GPU_viewport_size_get_f(viewport_size);
    immUniform2f("viewport_size", viewport_size[2], viewport_size[3]);

    immUniform1i("colors_len", 2); /* "advanced" mode */
    const float *col = is_act ? color_act : color_base;
    immUniformArray4fv(
        "colors",
        (float *)(float[][4]){{0.67f, 0.67f, 0.67f, 1.0f}, {col[0], col[1], col[2], col[3]}},
        2);
    immUniform1f("dash_width", 6.0f);
    immUniform1f("dash_factor", 0.5f);

    immBegin(GPU_PRIM_LINE_STRIP, 3);

    immVertex2fv(shdr_pos, co_ss[0]);
    immVertex2fv(shdr_pos, co_ss[1]);
    immVertex2fv(shdr_pos, co_ss[2]);

    immEnd();

    immUnbindProgram();

    immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);

    /* arc */
    {
      float dir_tmp[3];
      float co_tmp[3];
      float arc_ss_coord[2];

      float dir_a[3];
      float dir_b[3];
      float quat[4];
      float axis[3];
      float angle;
      const float px_scale = (ED_view3d_pixel_size_no_ui_scale(rv3d, ruler_item->co[1]) *
                              min_fff(arc_size,
                                      len_v2v2(co_ss[0], co_ss[1]) / 2.0f,
                                      len_v2v2(co_ss[2], co_ss[1]) / 2.0f));

      sub_v3_v3v3(dir_a, ruler_item->co[0], ruler_item->co[1]);
      sub_v3_v3v3(dir_b, ruler_item->co[2], ruler_item->co[1]);
      normalize_v3(dir_a);
      normalize_v3(dir_b);

      cross_v3_v3v3(axis, dir_a, dir_b);
      angle = angle_normalized_v3v3(dir_a, dir_b);

      axis_angle_to_quat(quat, axis, angle / arc_steps);

      copy_v3_v3(dir_tmp, dir_a);

      immUniformColor3ubv(color_wire);

      immBegin(GPU_PRIM_LINE_STRIP, arc_steps + 1);

      for (j = 0; j <= arc_steps; j++) {
        madd_v3_v3v3fl(co_tmp, ruler_item->co[1], dir_tmp, px_scale);
        ED_view3d_project_float_global(ar, co_tmp, arc_ss_coord, V3D_PROJ_TEST_NOP);
        mul_qt_v3(quat, dir_tmp);

        immVertex2fv(shdr_pos, arc_ss_coord);
      }

      immEnd();
    }

    /* capping */
    {
      float rot_90_vec_a[2];
      float rot_90_vec_b[2];
      float cap[2];

      sub_v2_v2v2(dir_ruler, co_ss[0], co_ss[1]);
      rot_90_vec_a[0] = -dir_ruler[1];
      rot_90_vec_a[1] = dir_ruler[0];
      normalize_v2(rot_90_vec_a);

      sub_v2_v2v2(dir_ruler, co_ss[1], co_ss[2]);
      rot_90_vec_b[0] = -dir_ruler[1];
      rot_90_vec_b[1] = dir_ruler[0];
      normalize_v2(rot_90_vec_b);

      GPU_blend(true);

      if (is_act && (ruler_item->flag & RULERITEM_USE_ANGLE_ACTIVE)) {
        GPU_line_width(3.0f);
        immUniformColor3fv(color_act);
        immBegin(GPU_PRIM_LINES, 4);
        /* angle vertex */
        immVertex2f(shdr_pos, co_ss[1][0] - cap_size, co_ss[1][1] - cap_size);
        immVertex2f(shdr_pos, co_ss[1][0] + cap_size, co_ss[1][1] + cap_size);
        immVertex2f(shdr_pos, co_ss[1][0] - cap_size, co_ss[1][1] + cap_size);
        immVertex2f(shdr_pos, co_ss[1][0] + cap_size, co_ss[1][1] - cap_size);

        immEnd();
        GPU_line_width(1.0f);
      }

      immUniformColor3ubv(color_wire);

      immBegin(GPU_PRIM_LINES, 8);

      madd_v2_v2v2fl(cap, co_ss[0], rot_90_vec_a, cap_size);
      immVertex2fv(shdr_pos, cap);
      madd_v2_v2v2fl(cap, co_ss[0], rot_90_vec_a, -cap_size);
      immVertex2fv(shdr_pos, cap);

      madd_v2_v2v2fl(cap, co_ss[2], rot_90_vec_b, cap_size);
      immVertex2fv(shdr_pos, cap);
      madd_v2_v2v2fl(cap, co_ss[2], rot_90_vec_b, -cap_size);
      immVertex2fv(shdr_pos, cap);

      /* angle vertex */
      immVertex2f(shdr_pos, co_ss[1][0] - cap_size, co_ss[1][1] - cap_size);
      immVertex2f(shdr_pos, co_ss[1][0] + cap_size, co_ss[1][1] + cap_size);
      immVertex2f(shdr_pos, co_ss[1][0] - cap_size, co_ss[1][1] + cap_size);
      immVertex2f(shdr_pos, co_ss[1][0] + cap_size, co_ss[1][1] - cap_size);

      immEnd();

      GPU_blend(false);
    }

    /* text */
    char numstr[256];
    float numstr_size[2];
    float posit[2];
    const int prec = 2; /* XXX, todo, make optional */

    ruler_item_as_string(ruler_item, unit, numstr, sizeof(numstr), prec);

    BLF_width_and_height(blf_mono_font, numstr, sizeof(numstr), &numstr_size[0], &numstr_size[1]);

    posit[0] = co_ss[1][0] + (cap_size * 2.0f);
    posit[1] = co_ss[1][1] - (numstr_size[1] / 2.0f);

    /* draw text (bg) */
    {
      immUniformColor4fv(color_back);
      GPU_blend(true);
      immRectf(shdr_pos,
               posit[0] - bg_margin,
               posit[1] - bg_margin,
               posit[0] + bg_margin + numstr_size[0],
               posit[1] + bg_margin + numstr_size[1]);
      GPU_blend(false);
    }

    immUnbindProgram();

    /* draw text */
    {
      BLF_color3ubv(blf_mono_font, color_text);
      BLF_position(blf_mono_font, posit[0], posit[1], 0.0f);
      BLF_rotation(blf_mono_font, 0.0f);
      BLF_draw(blf_mono_font, numstr, sizeof(numstr));
    }
  }
  else {
    immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_UNIFORM_COLOR);

    float viewport_size[4];
    GPU_viewport_size_get_f(viewport_size);
    immUniform2f("viewport_size", viewport_size[2], viewport_size[3]);

    immUniform1i("colors_len", 2); /* "advanced" mode */
    const float *col = is_act ? color_act : color_base;
    immUniformArray4fv(
        "colors",
        (float *)(float[][4]){{0.67f, 0.67f, 0.67f, 1.0f}, {col[0], col[1], col[2], col[3]}},
        2);
    immUniform1f("dash_width", 6.0f);
    immUniform1f("dash_factor", 0.5f);

    immBegin(GPU_PRIM_LINES, 2);

    immVertex2fv(shdr_pos, co_ss[0]);
    immVertex2fv(shdr_pos, co_ss[2]);

    immEnd();

    immUnbindProgram();

    immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);

    sub_v2_v2v2(dir_ruler, co_ss[0], co_ss[2]);

    /* capping */
    {
      float rot_90_vec[2] = {-dir_ruler[1], dir_ruler[0]};
      float cap[2];

      normalize_v2(rot_90_vec);

      GPU_blend(true);

      immUniformColor3ubv(color_wire);

      immBegin(GPU_PRIM_LINES, 4);

      madd_v2_v2v2fl(cap, co_ss[0], rot_90_vec, cap_size);
      immVertex2fv(shdr_pos, cap);
      madd_v2_v2v2fl(cap, co_ss[0], rot_90_vec, -cap_size);
      immVertex2fv(shdr_pos, cap);

      madd_v2_v2v2fl(cap, co_ss[2], rot_90_vec, cap_size);
      immVertex2fv(shdr_pos, cap);
      madd_v2_v2v2fl(cap, co_ss[2], rot_90_vec, -cap_size);
      immVertex2fv(shdr_pos, cap);

      immEnd();

      GPU_blend(false);
    }

    /* text */
    char numstr[256];
    float numstr_size[2];
    const int prec = 6; /* XXX, todo, make optional */
    float posit[2];

    ruler_item_as_string(ruler_item, unit, numstr, sizeof(numstr), prec);

    BLF_width_and_height(blf_mono_font, numstr, sizeof(numstr), &numstr_size[0], &numstr_size[1]);

    mid_v2_v2v2(posit, co_ss[0], co_ss[2]);

    /* center text */
    posit[0] -= numstr_size[0] / 2.0f;
    posit[1] -= numstr_size[1] / 2.0f;

    /* draw text (bg) */
    {
      immUniformColor4fv(color_back);
      GPU_blend(true);
      immRectf(shdr_pos,
               posit[0] - bg_margin,
               posit[1] - bg_margin,
               posit[0] + bg_margin + numstr_size[0],
               posit[1] + bg_margin + numstr_size[1]);
      GPU_blend(false);
    }

    immUnbindProgram();

    /* draw text */
    {
      BLF_color3ubv(blf_mono_font, color_text);
      BLF_position(blf_mono_font, posit[0], posit[1], 0.0f);
      BLF_draw(blf_mono_font, numstr, sizeof(numstr));
    }
  }

  GPU_line_smooth(false);

  BLF_disable(blf_mono_font, BLF_ROTATION);

#undef ARC_STEPS

  /* draw snap */
  if ((ruler_info->snap_flag & RULER_SNAP_OK) && (ruler_info->state == RULER_STATE_DRAG) &&
      (ruler_item->gz.interaction_data != NULL)) {
    RulerInteraction *inter = ruler_item->gz.interaction_data;
    /* size from drawSnapping */
    const float size = 2.5f * UI_GetThemeValuef(TH_VERTEX_SIZE);
    float co_ss_snap[3];
    ED_view3d_project_float_global(
        ar, ruler_item->co[inter->co_index], co_ss_snap, V3D_PROJ_TEST_NOP);

    uint pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);

    immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);
    immUniformColor4fv(color_act);

    imm_draw_circle_wire_2d(pos, co_ss_snap[0], co_ss_snap[1], size * U.pixelsize, 32);

    immUnbindProgram();
  }
}

static int gizmo_ruler_test_select(bContext *UNUSED(C), wmGizmo *gz, const int mval[2])
{
  RulerItem *ruler_item_pick = (RulerItem *)gz;
  float mval_fl[2] = {UNPACK2(mval)};
  int co_index;

  /* select and drag */
  if (view3d_ruler_pick(gz->parent_gzgroup, ruler_item_pick, mval_fl, &co_index)) {
    if (co_index == -1) {
      if ((ruler_item_pick->flag & RULERITEM_USE_ANGLE) == 0) {
        return PART_LINE;
      }
    }
    else {
      return co_index;
    }
  }
  return -1;
}

static int gizmo_ruler_modal(bContext *C,
                             wmGizmo *gz,
                             const wmEvent *event,
                             eWM_GizmoFlagTweak tweak_flag)
{
  bool do_draw = false;
  int exit_code = OPERATOR_RUNNING_MODAL;
  RulerInfo *ruler_info = gz->parent_gzgroup->customdata;
  RulerItem *ruler_item = (RulerItem *)gz;
  ARegion *ar = CTX_wm_region(C);
  bool do_cursor_update = false;

  ruler_info->ar = ar;

  switch (event->type) {
    case MOUSEMOVE: {
      do_cursor_update = true;
      break;
    }
  }

  const bool do_snap = tweak_flag & WM_GIZMO_TWEAK_SNAP;
  const bool do_thickness = tweak_flag & WM_GIZMO_TWEAK_PRECISE;
  if ((ruler_info->drag_state_prev.do_snap != do_snap) ||
      (ruler_info->drag_state_prev.do_thickness != do_thickness)) {
    do_cursor_update = true;
  }

  if (do_cursor_update) {
    if (ruler_info->state == RULER_STATE_DRAG) {
      if (view3d_ruler_item_mousemove(
              ruler_info, ruler_item, event->mval, do_thickness, do_snap)) {
        do_draw = true;
      }
    }
  }

  ruler_info->drag_state_prev.do_snap = do_snap;
  ruler_info->drag_state_prev.do_thickness = do_thickness;

  if (do_draw) {
    ED_region_tag_redraw(ar);
  }
  return exit_code;
}

static int gizmo_ruler_invoke(bContext *C, wmGizmo *gz, const wmEvent *event)
{
  wmGizmoGroup *gzgroup = gz->parent_gzgroup;
  RulerInfo *ruler_info = gzgroup->customdata;
  RulerItem *ruler_item_pick = (RulerItem *)gz;
  RulerInteraction *inter = MEM_callocN(sizeof(RulerInteraction), __func__);
  gz->interaction_data = inter;

  ARegion *ar = ruler_info->ar;

  const float mval_fl[2] = {UNPACK2(event->mval)};

  /* select and drag */
  if (gz->highlight_part == PART_LINE) {
    if ((ruler_item_pick->flag & RULERITEM_USE_ANGLE) == 0) {
      /* Add Center Point */
      ruler_item_pick->flag |= RULERITEM_USE_ANGLE;
      inter->co_index = 1;
      ruler_state_set(C, ruler_info, RULER_STATE_DRAG);

      /* find the factor */
      {
        float co_ss[2][2];
        float fac;

        ED_view3d_project_float_global(ar, ruler_item_pick->co[0], co_ss[0], V3D_PROJ_TEST_NOP);
        ED_view3d_project_float_global(ar, ruler_item_pick->co[2], co_ss[1], V3D_PROJ_TEST_NOP);

        fac = line_point_factor_v2(mval_fl, co_ss[0], co_ss[1]);
        CLAMP(fac, 0.0f, 1.0f);

        interp_v3_v3v3(
            ruler_item_pick->co[1], ruler_item_pick->co[0], ruler_item_pick->co[2], fac);
      }

      /* update the new location */
      view3d_ruler_item_mousemove(ruler_info, ruler_item_pick, event->mval, false, false);
    }
  }
  else {
    inter->co_index = gz->highlight_part;
    ruler_state_set(C, ruler_info, RULER_STATE_DRAG);

    /* store the initial depth */
    copy_v3_v3(inter->drag_start_co, ruler_item_pick->co[inter->co_index]);
  }

  if (inter->co_index == 1) {
    ruler_item_pick->flag |= RULERITEM_USE_ANGLE_ACTIVE;
  }
  else {
    ruler_item_pick->flag &= ~RULERITEM_USE_ANGLE_ACTIVE;
  }

  ruler_info->item_active = ruler_item_pick;

  return OPERATOR_RUNNING_MODAL;
}

static void gizmo_ruler_exit(bContext *C, wmGizmo *gz, const bool cancel)
{
  wmGizmoGroup *gzgroup = gz->parent_gzgroup;
  RulerInfo *ruler_info = gzgroup->customdata;

  if (!cancel) {
    if (ruler_info->state == RULER_STATE_DRAG) {
      if (ruler_info->snap_flag & RULER_SNAP_OK) {
        ruler_info->snap_flag &= ~RULER_SNAP_OK;
      }
      ruler_state_set(C, ruler_info, RULER_STATE_NORMAL);
    }
    /* We could convert only the current gizmo, for now just re-generate. */
    view3d_ruler_to_gpencil(C, gzgroup);
  }

  if (gz) {
    MEM_SAFE_FREE(gz->interaction_data);
  }

  ruler_state_set(C, ruler_info, RULER_STATE_NORMAL);
}

static int gizmo_ruler_cursor_get(wmGizmo *gz)
{
  if (gz->highlight_part == PART_LINE) {
    return BC_CROSSCURSOR;
  }
  return BC_NSEW_SCROLLCURSOR;
}

void VIEW3D_GT_ruler_item(wmGizmoType *gzt)
{
  /* identifiers */
  gzt->idname = "VIEW3D_GT_ruler_item";

  /* api callbacks */
  gzt->draw = gizmo_ruler_draw;
  gzt->test_select = gizmo_ruler_test_select;
  gzt->modal = gizmo_ruler_modal;
  gzt->invoke = gizmo_ruler_invoke;
  gzt->exit = gizmo_ruler_exit;
  gzt->cursor_get = gizmo_ruler_cursor_get;

  gzt->struct_size = sizeof(RulerItem);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Ruler Gizmo Group
 * \{ */

static void WIDGETGROUP_ruler_setup(const bContext *C, wmGizmoGroup *gzgroup)
{
  RulerInfo *ruler_info = MEM_callocN(sizeof(RulerInfo), __func__);

  if (view3d_ruler_from_gpencil(C, gzgroup)) {
    /* nop */
  }

  wmWindow *win = CTX_wm_window(C);
  ScrArea *sa = CTX_wm_area(C);
  ARegion *ar = CTX_wm_region(C);
  ruler_info->win = win;
  ruler_info->sa = sa;
  ruler_info->ar = ar;

  gzgroup->customdata = ruler_info;
}

void VIEW3D_GGT_ruler(wmGizmoGroupType *gzgt)
{
  gzgt->name = "Ruler Widgets";
  gzgt->idname = view3d_gzgt_ruler_id;

  gzgt->flag |= WM_GIZMOGROUPTYPE_SCALE | WM_GIZMOGROUPTYPE_DRAW_MODAL_ALL;

  gzgt->gzmap_params.spaceid = SPACE_VIEW3D;
  gzgt->gzmap_params.regionid = RGN_TYPE_WINDOW;

  gzgt->poll = ED_gizmo_poll_or_unlink_delayed_from_tool;
  gzgt->setup = WIDGETGROUP_ruler_setup;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Add Ruler Operator
 * \{ */

static bool view3d_ruler_poll(bContext *C)
{
  bToolRef_Runtime *tref_rt = WM_toolsystem_runtime_from_context((bContext *)C);
  if ((tref_rt == NULL) || !STREQ(view3d_gzgt_ruler_id, tref_rt->gizmo_group) ||
      CTX_wm_region_view3d(C) == NULL) {
    return false;
  }
  return true;
}

static int view3d_ruler_add_invoke(bContext *C, wmOperator *op, const wmEvent *event)
{
  ARegion *ar = CTX_wm_region(C);
  View3D *v3d = CTX_wm_view3d(C);
  RegionView3D *rv3d = ar->regiondata;

  if (v3d->gizmo_flag & (V3D_GIZMO_HIDE | V3D_GIZMO_HIDE_TOOL)) {
    BKE_report(op->reports, RPT_WARNING, "Gizmos hidden in this view");
    return OPERATOR_CANCELLED;
  }

  wmGizmoMap *gzmap = ar->gizmo_map;
  wmGizmoGroup *gzgroup = WM_gizmomap_group_find(gzmap, view3d_gzgt_ruler_id);
  const bool use_depth = (v3d->shading.type >= OB_SOLID);

  /* Create new line */
  RulerItem *ruler_item;
  ruler_item = ruler_item_add(gzgroup);

  /* This is a little weak, but there is no real good way to tweak directly. */
  WM_gizmo_highlight_set(gzmap, &ruler_item->gz);
  if (WM_operator_name_call(C, "GIZMOGROUP_OT_gizmo_tweak", WM_OP_INVOKE_REGION_WIN, NULL) ==
      OPERATOR_RUNNING_MODAL) {
    RulerInfo *ruler_info = gzgroup->customdata;
    RulerInteraction *inter = ruler_item->gz.interaction_data;
    if (use_depth) {
      /* snap the first point added, not essential but handy */
      inter->co_index = 0;
      view3d_ruler_item_mousemove(ruler_info, ruler_item, event->mval, false, true);
      copy_v3_v3(inter->drag_start_co, ruler_item->co[inter->co_index]);
    }
    else {
      negate_v3_v3(inter->drag_start_co, rv3d->ofs);
      copy_v3_v3(ruler_item->co[0], inter->drag_start_co);
      view3d_ruler_item_project(ruler_info, ruler_item->co[0], event->mval);
    }

    copy_v3_v3(ruler_item->co[2], ruler_item->co[0]);
    ruler_item->gz.highlight_part = inter->co_index = 2;
  }
  return OPERATOR_FINISHED;
}

void VIEW3D_OT_ruler_add(wmOperatorType *ot)
{
  /* identifiers */
  ot->name = "Ruler Add";
  ot->idname = "VIEW3D_OT_ruler_add";

  ot->invoke = view3d_ruler_add_invoke;
  ot->poll = view3d_ruler_poll;

  /* flags */
  ot->flag = OPTYPE_UNDO | OPTYPE_INTERNAL;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Remove Ruler Operator
 * \{ */

static int view3d_ruler_remove_invoke(bContext *C, wmOperator *op, const wmEvent *UNUSED(event))
{
  ARegion *ar = CTX_wm_region(C);
  View3D *v3d = CTX_wm_view3d(C);

  if (v3d->gizmo_flag & (V3D_GIZMO_HIDE | V3D_GIZMO_HIDE_TOOL)) {
    BKE_report(op->reports, RPT_WARNING, "Gizmos hidden in this view");
    return OPERATOR_CANCELLED;
  }

  wmGizmoMap *gzmap = ar->gizmo_map;
  wmGizmoGroup *gzgroup = WM_gizmomap_group_find(gzmap, view3d_gzgt_ruler_id);
  if (gzgroup) {
    RulerInfo *ruler_info = gzgroup->customdata;
    if (ruler_info->item_active) {
      RulerItem *ruler_item = ruler_info->item_active;
      if ((ruler_item->flag & RULERITEM_USE_ANGLE) &&
          (ruler_item->flag & RULERITEM_USE_ANGLE_ACTIVE)) {
        ruler_item->flag &= ~(RULERITEM_USE_ANGLE | RULERITEM_USE_ANGLE_ACTIVE);
      }
      else {
        ruler_item_remove(C, gzgroup, ruler_item);
      }
      ED_region_tag_redraw(ar);
      return OPERATOR_FINISHED;
    }
  }
  return OPERATOR_PASS_THROUGH;
}

void VIEW3D_OT_ruler_remove(wmOperatorType *ot)
{
  /* identifiers */
  ot->name = "Ruler Remove";
  ot->idname = "VIEW3D_OT_ruler_remove";

  ot->invoke = view3d_ruler_remove_invoke;
  ot->poll = view3d_ruler_poll;

  /* flags */
  ot->flag = OPTYPE_UNDO | OPTYPE_INTERNAL;
}

/** \} */