view3d_mesh_draw_hoever.py

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bl_info = {
    'name': 'EDGE Visualiser (BMesh)',
    'author': 'zeffii',
    'version': (0, 0, 1),
    'blender': (2, 7, 0),
    'location': '',
    'warning': '',
    'description': '',
    'wiki_url': '',
    'tracker_url': '',
    'category': '3D View'
}


"""
Display the indices of vertices, edges and faces in the 3d-view.

How to use:
- Select a mesh and go into editmode
- Display the properties panel (N-key)
- Go to the Mesh Display tab, it helps to fold the tabs above it
- Press the 'Visualise indices button'

"""

import bpy
import bgl
import blf
import mathutils
import bmesh
import math
from bpy_extras.view3d_utils import location_3d_to_region_2d as loc3d2d

point_dict = {}


def adjust_list(in_list, x, y):
    return [[old_x + x, old_y + y] for (old_x, old_y) in in_list]


def generate_points(width, height, amp=5):
    ''' amp: radius fillet '''

    width += 2
    height += 4
    width = ((width/2) - amp) + 2
    height -= (2*amp)

    pos_list, final_list = [], []

    n_points = 10
    seg_angle = 2 * math.pi / n_points
    for i in range(n_points + 1):
        angle = i * seg_angle
        x = math.cos(angle) * amp
        y = math.sin(angle) * amp
        pos_list.append([x, -y])

    w_list, h_list = [1, -1, -1, 1], [-1, -1, 1, 1]
    slice_list = [[i, i+4] for i in range(0, n_points, 3)]

    for idx, (start, end) in enumerate(slice_list):
        point_array = pos_list[start:end]
        w = width * w_list[idx]
        h = height * h_list[idx]
        final_list += adjust_list(point_array, w, h)

    return final_list


def get_points(index):
    '''
    index:   string representation of the index number
    returns: rounded rect point_list used for background.

    the neat thing about this is if a width has been calculated once, it
    is stored in a dict and used if another polygon is saught with that width.
    '''
    width, height = blf.dimensions(0, index)
    if not (width in point_dict):
        point_dict[width] = generate_points(width, height)

    return point_dict[width]


# calculate locations and store them as ID property in the mesh
def draw_callback_px(self, context):
    # polling
    if context.mode != "EDIT_MESH":
        return

    # get screen information
    region = context.region
    rv3d = context.space_data.region_3d
    this_object = context.active_object
    matrix_world = this_object.matrix_world

    text_height = 13
    blf.size(0, text_height, 72)

    def draw_index(rgb, index, coord):

        vector3d = matrix_world * coord
        x, y = loc3d2d(region, rv3d, vector3d)

        index = str(index)
        polyline = get_points(index)

        ''' draw polygon '''
        bgl.glColor4f(0.103, 0.2, 0.2, 0.2)
        bgl.glBegin(bgl.GL_POLYGON)
        for pointx, pointy in polyline:
            bgl.glVertex2f(pointx+x, pointy+y)
        bgl.glEnd()

        ''' draw text '''
        txt_width, txt_height = blf.dimensions(0, index)
        bgl.glColor3f(*rgb)
        blf.position(0, x - (txt_width / 2), y - (txt_height / 2), 0)
        blf.draw(0, index)

    vert_idx_color = (1.0, 1.0, 1.0)
    edge_idx_color = (1.0, 1.0, 0.0)
    face_idx_color = (1.0, 0.8, 0.8)

    scene = context.scene
    me = context.active_object.data
    bm = bmesh.from_edit_mesh(me)

    #if scene.live_mode:
    me.update()

    if True:
        for e in bm.edges:
            if not e.hide and e.select:
                v1 = e.verts[0].co
                v2 = e.verts[1].co
                loc = v1 + ((v2 - v1) / 2)
                draw_index(edge_idx_color, e.index, loc.to_4d())


# operator
class EdgeHover(bpy.types.Operator):
    bl_idname = "view3d.edge_visualiser"
    bl_label = "EDGE Visualiser"
    bl_description = "Toggle the visualisation of indices"

    _handle = None

    @classmethod
    def poll(cls, context):
        return context.mode == "EDIT_MESH"

    def modal(self, context, event):

        if event.type in ('RET'):
            bpy.types.SpaceView3D.draw_handler_remove(self._handle, 'WINDOW')
            # from here it is possible to call mesh updates.
            return {"CANCELLED"}

        if context.area:
            context.area.tag_redraw()
            return {"PASS_THROUGH"}

    def invoke(self, context, event):
        if context.area.type == "VIEW_3D":
            sc = (self, context)
            w = 'WINDOW'
            pp = 'POST_PIXEL'
            draw_handler = bpy.types.SpaceView3D.draw_handler_add
            self._handle = draw_handler(draw_callback_px, sc, w, pp)

            context.window_manager.modal_handler_add(self)
            return {"RUNNING_MODAL"}
        else:
            self.report({"WARNING"}, "View3D not found, can't run operator")
            return {"CANCELLED"}


def register():
    bpy.utils.register_class(EdgeHover)


def unregister():
    bpy.utils.unregister_class(EdgeHover)


if __name__ == "__main__":
    register()