Geografic-Information-System/gui/wxpython/nviz/wxnviz.py

"""
@package nviz.wxnviz

@brief wxGUI 3D view mode (ctypes-based classes)

This module implements 3D visualization mode for map display (ctypes
required).

List of classes:
 - wxnviz::Nviz
 - wxnviz::Texture
 - wxnviz::ImageTexture
 - wxnviz::TextTexture

(C) 2008-2011 by the GRASS Development Team

This program is free software under the GNU General Public License
(>=v2). Read the file COPYING that comes with GRASS for details.

@author Martin Landa <landa.martin gmail.com> (Google SoC 2008/2010)
@author Pythonized by Glynn Clements
@author Anna Kratochvilova <KratochAnna seznam.cz> (Google SoC 2011)
"""

import sys
import locale
import struct
from math import sqrt
try:
    from numpy import matrix
except ImportError:
    msg = _(
        "This module requires the NumPy module, which could not be "
        "imported. It probably is not installed (it's not part of the "
        "standard Python distribution). See the Numeric Python site "
        "(http://numpy.scipy.org) for information on downloading source or "
        "binaries.")
    print >> sys.stderr, "wxnviz.py: " + msg

import wx

from ctypes import *

from grass.lib.gis import *
from grass.lib.raster3d import *
from grass.lib.vector import *
from grass.lib.ogsf import *
from grass.lib.nviz import *
from grass.lib.raster import *

from core.debug import Debug
from core.utils import _, autoCropImageFromFile
import grass.script as grass

log = None
progress = None


def print_error(msg, type):
    """Redirect stderr"""
    global log
    if log:
        log.write(msg)
    else:
        print msg

    return 0


def print_progress(value):
    """Redirect progress info"""
    global progress
    if progress:
        if not progress.GetRange() == 100:
            progress.SetRange(100)
        progress.SetValue(value)
    else:
        print value

    return 0

try:
    errtype = CFUNCTYPE(UNCHECKED(c_int), String, c_int)
    errfunc = errtype(print_error)
    pertype = CFUNCTYPE(UNCHECKED(c_int), c_int)
    perfunc = pertype(print_progress)
except NameError:
    pass


class Nviz(object):

    def __init__(self, glog, gprogress):
        """Initialize Nviz class instance

        :param glog: logging area
        :param gprogress: progressbar
        """
        global errfunc, perfunc, log, progress
        log = glog
        progress = gprogress

        G_gisinit("wxnviz")
        # gislib is already initialized (where?)
        G_set_error_routine(errfunc)
        G_set_percent_routine(perfunc)

        self.Init()

        self.data_obj = nv_data()
        self.data = pointer(self.data_obj)
        self.color_obj = Colors()
        self.color = pointer(self.color_obj)

        self.width = self.height = -1
        self.showLight = False

        Debug.msg(1, "Nviz::Nviz()")

    def __del__(self):
        """Destroy Nviz class instance"""
        G_unset_error_routine()
        G_unset_percent_routine()
        del self.data
        del self.data_obj
        self.log = None

    def Init(self):
        """Initialize window"""
        locale.setlocale(locale.LC_NUMERIC, 'C')
        G_unset_window()
        Rast_unset_window()
        Rast__init_window()
        GS_libinit()
        GVL_libinit()
        GVL_init_region()

    def ResizeWindow(self, width, height):
        """GL canvas resized

        :param width: window width
        :param height: window height

        :return: 1 on success
        :return: 0 on failure (window resized by default to 20x20 px)
        """
        self.width = width
        self.height = height
        Debug.msg(3, "Nviz::ResizeWindow(): width=%d height=%d",
                  width, height)
        return Nviz_resize_window(width, height)

    def GetLongDim(self):
        """Get longest dimension, used for initial size of north arrow"""
        return Nviz_get_longdim(self.data)

    def SetViewDefault(self):
        """Set default view (based on loaded data)

        :return: z-exag value, default, min and max height
        """
        # determine z-exag
        z_exag = Nviz_get_exag()
        Nviz_change_exag(self.data, z_exag)

        # determine height
        hdef = c_double()
        hmin = c_double()
        hmax = c_double()
        Nviz_get_exag_height(byref(hdef), byref(hmin), byref(hmax))

        Debug.msg(1, "Nviz::SetViewDefault(): hdef=%f, hmin=%f, hmax=%f",
                  hdef.value, hmin.value, hmax.value)

        return (z_exag, hdef.value, hmin.value, hmax.value)

    def SetView(self, x, y, height, persp, twist):
        """Change view settings
        :param x,y: position
        :param height:
        :param persp: perpective
        :param twist:
        """
        Nviz_set_viewpoint_height(height)
        Nviz_set_viewpoint_position(x, y)
        Nviz_set_viewpoint_twist(twist)
        Nviz_set_viewpoint_persp(persp)

        Debug.msg(
            3,
            "Nviz::SetView(): x=%f, y=%f, height=%f, persp=%f, twist=%f",
            x,
            y,
            height,
            persp,
            twist)

    def GetViewpointPosition(self):
        x = c_double()
        y = c_double()
        h = c_double()
        Nviz_get_viewpoint_height(byref(h))
        Nviz_get_viewpoint_position(byref(x), byref(y))

        return (x.value, y.value, h.value)

    def LookHere(self, x, y):
        """Look here feature
        :param x,y: screen coordinates
        """

        Nviz_look_here(x, y)
        Debug.msg(3, "Nviz::LookHere(): x=%f, y=%f", x, y)

    def LookAtCenter(self):
        """Center view at center of displayed surface"""
        Nviz_set_focus_map(MAP_OBJ_UNDEFINED, -1)
        Debug.msg(3, "Nviz::LookAtCenter()")

    def GetFocus(self):
        """Get focus"""
        Debug.msg(3, "Nviz::GetFocus()")
        if Nviz_has_focus(self.data):
            x = c_float()
            y = c_float()
            z = c_float()
            Nviz_get_focus(self.data, byref(x), byref(y), byref(z))
            return x.value, y.value, z.value
        else:
            return -1, -1, -1

    def SetFocus(self, x, y, z):
        """Set focus"""
        Debug.msg(3, "Nviz::SetFocus()")
        Nviz_set_focus(self.data, x, y, z)

    def GetViewdir(self):
        """Get viewdir"""
        Debug.msg(3, "Nviz::GetViewdir()")
        dir = (c_float * 3)()
        GS_get_viewdir(byref(dir))

        return dir[0], dir[1], dir[2]

    def SetViewdir(self, x, y, z):
        """Set viewdir"""
        Debug.msg(3, "Nviz::SetViewdir(): x=%f, y=%f, z=%f" % (x, y, z))
        dir = (c_float * 3)()
        for i, coord in enumerate((x, y, z)):
            dir[i] = coord
        GS_set_viewdir(byref(dir))

    def SetZExag(self, z_exag):
        """Set z-exag value

        :param z_exag: value

        :return: 1
        """
        Debug.msg(3, "Nviz::SetZExag(): z_exag=%f", z_exag)
        return Nviz_change_exag(self.data, z_exag)

    def Draw(self, quick, quick_mode):
        """Draw canvas

        Draw quick mode:
         - DRAW_QUICK_SURFACE
         - DRAW_QUICK_VLINES
         - DRAW_QUICK_VPOINTS
         - DRAW_QUICK_VOLUME

        :param quick: if true draw in wiremode
        :param quick_mode: quick mode
        """
        Debug.msg(3, "Nviz::Draw(): quick=%d", quick)

        Nviz_draw_cplane(self.data, -1, -1)  # ?

        if quick:
            Nviz_draw_quick(self.data, quick_mode)
        else:
            Nviz_draw_all(self.data)

    def EraseMap(self):
        """Erase map display (with background color)
        """
        Debug.msg(1, "Nviz::EraseMap()")
        GS_clear(Nviz_get_bgcolor(self.data))

    def InitView(self):
        """Initialize view"""
        # initialize nviz data
        Nviz_init_data(self.data)

        # define default attributes for map objects
        Nviz_set_surface_attr_default()
        # set background color
        Nviz_set_bgcolor(self.data, Nviz_color_from_str("white"))

        GS_clear(Nviz_get_bgcolor(self.data))
        # initialize view, lights
        Nviz_init_view(self.data)

        Debug.msg(1, "Nviz::InitView()")

    def SetBgColor(self, color_str):
        """Set background color

        :param str color_str: color string
        """
        Nviz_set_bgcolor(self.data, Nviz_color_from_str(color_str))

    def SetLight(self, x, y, z, color, bright, ambient, w=0, lid=1):
        """Change lighting settings

        :param x,y,z: position
        :param color: light color (as string)
        :param bright: light brightness
        :param ambient: light ambient
        :param w: local coordinate (default to 0)
        :param lid: light id
        """
        Nviz_set_light_position(self.data, lid, x, y, z, w)
        Nviz_set_light_bright(self.data, lid, bright)
        Nviz_set_light_color(
            self.data, lid, int(
                color[0]), int(
                color[1]), int(
                color[2]))
        Nviz_set_light_ambient(self.data, lid, ambient)

    def LoadSurface(self, name, color_name, color_value):
        """Load raster map (surface)

        :param name: raster map name
        :param color_name: raster map for color (None for color_value)
        :param color_value: color string (named color or RGB triptet)

        :return: object id
        :return: -1 on failure
        """
        mapset = G_find_raster2(name, "")
        if mapset is None:
            G_warning(_("Raster map <%s> not found"), name)
            return -1

        # topography
        id = Nviz_new_map_obj(MAP_OBJ_SURF,
                              G_fully_qualified_name(name, mapset), 0.0,
                              self.data)

        if color_name:      # check for color map
            mapset = G_find_raster2(color_name, "")
            if mapset is None:
                G_warning(_("Raster map <%s> not found"), color_name)
                GS_delete_surface(id)
                return -1

            Nviz_set_attr(id, MAP_OBJ_SURF, ATT_COLOR, MAP_ATT,
                          G_fully_qualified_name(color_name, mapset), -1.0,
                          self.data)

        elif color_value:   # check for color value
            Nviz_set_attr(id, MAP_OBJ_SURF, ATT_COLOR, CONST_ATT,
                          None, Nviz_color_from_str(color_value),
                          self.data)

        else:               # use by default elevation map for coloring
            Nviz_set_attr(id, MAP_OBJ_SURF, ATT_COLOR, MAP_ATT,
                          G_fully_qualified_name(name, mapset), -1.0,
                          self.data)

        # if (i > 1)
        #     set_default_wirecolors(self.data, i)

        # focus on loaded self.data
        Nviz_set_focus_map(MAP_OBJ_UNDEFINED, -1)

        Debug.msg(1, "Nviz::LoadRaster(): name=%s -> id=%d", name, id)

        return id

    def AddConstant(self, value, color):
        """Add new constant surface"""
        id = Nviz_new_map_obj(MAP_OBJ_SURF, None, value, self.data)

        Nviz_set_attr(id, MAP_OBJ_SURF, ATT_COLOR, CONST_ATT,
                      None, Nviz_color_from_str(color),
                      self.data)
        Nviz_set_focus_map(MAP_OBJ_UNDEFINED, -1)

        Debug.msg(1, "Nviz::AddConstant(): id=%d", id)
        return id

    def UnloadSurface(self, id):
        """Unload surface

        :param id: surface id

        :return: 1 on success
        :return: 0 on failure
        """
        if not GS_surf_exists(id):
            return 0

        Debug.msg(1, "Nviz::UnloadSurface(): id=%d", id)

        if GS_delete_surface(id) < 0:
            return 0

        return 1

    def LoadVector(self, name, points):
        """Load vector map overlay

        :param name: vector map name
        :param points: if true load 2d points rather then 2d lines

        :return: object id, id of base surface (or -1 if it is not loaded)
        :return: -1 on failure
        """
        baseId = -1
        if GS_num_surfs() == 0:     # load base surface if no loaded
            baseId = Nviz_new_map_obj(MAP_OBJ_SURF, None, 0.0, self.data)

            nsurf = c_int()
            surf_list = GS_get_surf_list(byref(nsurf))
            GS_set_att_const(surf_list[0], ATT_TRANSP, 255)

        mapset = G_find_vector2(name, "")
        if mapset is None:
            G_warning(_("Vector map <%s> not found"),
                      name)

        if points:
            id = Nviz_new_map_obj(MAP_OBJ_SITE,
                                  G_fully_qualified_name(name, mapset), 0.0,
                                  self.data)
        else:
            id = Nviz_new_map_obj(MAP_OBJ_VECT,
                                  G_fully_qualified_name(name, mapset), 0.0,
                                  self.data)

        Debug.msg(1, "Nviz::LoadVector(): name=%s -> id=%d", name, id)

        return id, baseId

    def UnloadVector(self, id, points):
        """Unload vector set

        :param id: vector set id
        :param points: vector points or lines set

        :return: 1 on success
        :return: 0 on failure
        """
        Debug.msg(1, "Nviz::UnloadVector(): id=%d", id)

        if points:
            if not GP_site_exists(id):
                return 0
            if GP_delete_site(id) < 0:
                return 0
        else:
            if not GV_vect_exists(id):
                return 0
            if GV_delete_vector(id) < 0:
                return 0

        return 1

    def VectorSurfaceSelected(self, vid, sid):
        """Check if surface is selected (currently unused)

        :param vid: vector id
        :param sid: surface id

        :return: True if selected
        :return: False if not selected
        """
        selected = GV_surf_is_selected(vid, sid)
        Debug.msg(
            1,
            "Nviz::VectorSurfaceSelected(): vid=%s, sid=%d -> selected=%d",
            vid,
            sid,
            selected)
        return selected

    def LoadVolume(self, name, color_name, color_value):
        """Load 3d raster map (volume)

        :param name: 3d raster map name
        :param color_name: 3d raster map for color (None for color_value)
        :param color_value: color string (named color or RGB triptet)

        :return: object id
        :return: -1 on failure
        """
        mapset = G_find_raster3d(name, "")
        if mapset is None:
            G_warning(_("3d raster map <%s> not found"),
                      name)
            return -1

        # topography
        id = Nviz_new_map_obj(MAP_OBJ_VOL,
                              G_fully_qualified_name(name, mapset), 0.0,
                              self.data)

        if color_name:      # check for color map
            mapset = G_find_raster3d(color_name, "")
            if mapset is None:
                G_warning(_("3d raster map <%s> not found"),
                          color_name)
                GVL_delete_vol(id)
                return -1

            Nviz_set_attr(id, MAP_OBJ_VOL, ATT_COLOR, MAP_ATT,
                          G_fully_qualified_name(color_name, mapset), -1.0,
                          self.data)
        elif color_value:   # check for color value
            Nviz_set_attr(id, MAP_OBJ_VOL, ATT_COLOR, CONST_ATT,
                          None, Nviz_color_from_str(color_value),
                          self.data)
        else:               # use by default elevation map for coloring
            Nviz_set_attr(id, MAP_OBJ_VOL, ATT_COLOR, MAP_ATT,
                          G_fully_qualified_name(name, mapset), -1.0,
                          self.data)

        Debug.msg(1, "Nviz::LoadVolume(): name=%s -> id=%d", name, id)

        return id

    def UnloadVolume(self, id):
        """Unload volume

        :param id: volume id

        :return: 1 on success
        :return: 0 on failure
        """
        if not GVL_vol_exists(id):
            return 0

        Debug.msg(1, "Nviz::UnloadVolume(): id=%d", id)

        if GVL_delete_vol(id) < 0:
            return 0

        return 1

    def SetSurfaceTopo(self, id, map, value):
        """Set surface topography

        :param id: surface id
        :param map: if true use map otherwise constant
        :param value: map name of value

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        """
        return self.SetSurfaceAttr(id, ATT_TOPO, map, value)

    def SetSurfaceColor(self, id, map, value):
        """Set surface color

        :param id: surface id
        :param map: if true use map otherwise constant
        :param value: map name or value

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        """
        return self.SetSurfaceAttr(id, ATT_COLOR, map, value)

    def SetSurfaceMask(self, id, invert, value):
        """Set surface mask

        .. todo::
            invert

        :param id: surface id
        :param invert: if true invert mask
        :param value: map name of value

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        """
        return self.SetSurfaceAttr(id, ATT_MASK, True, value)

    def SetSurfaceTransp(self, id, map, value):
        """Set surface mask

        ..todo::
            invert

        :param id: surface id
        :param map: if true use map otherwise constant
        :param value: map name of value

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        """
        return self.SetSurfaceAttr(id, ATT_TRANSP, map, value)

    def SetSurfaceShine(self, id, map, value):
        """Set surface shininess

        :param id: surface id
        :param map: if true use map otherwise constant
        :param value: map name of value

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        """
        return self.SetSurfaceAttr(id, ATT_SHINE, map, value)

    def SetSurfaceEmit(self, id, map, value):
        """Set surface emission (currently unused)

        :param id: surface id
        :param map: if true use map otherwise constant
        :param value: map name of value

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        """
        return self.SetSurfaceAttr(id, ATT_EMIT, map, value)

    def SetSurfaceAttr(self, id, attr, map, value):
        """Set surface attribute

        :param id: surface id
        :param attr: attribute desc
        :param map: if true use map otherwise constant
        :param value: map name of value

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        """
        if not GS_surf_exists(id):
            return -1

        if map:
            ret = Nviz_set_attr(id, MAP_OBJ_SURF, attr, MAP_ATT,
                                value, -1.0, self.data)
        else:
            if attr == ATT_COLOR:
                val = Nviz_color_from_str(value)
            else:
                val = float(value)

            ret = Nviz_set_attr(id, MAP_OBJ_SURF, attr, CONST_ATT,
                                None, val, self.data)

        Debug.msg(
            3,
            "Nviz::SetSurfaceAttr(): id=%d, attr=%d, map=%d, value=%s",
            id,
            attr,
            map,
            value)

        if ret < 0:
            return -2

        return 1

    def UnsetSurfaceMask(self, id):
        """Unset surface mask

        :param id: surface id

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        :return: -1 on failure
        """
        return self.UnsetSurfaceAttr(id, ATT_MASK)

    def UnsetSurfaceTransp(self, id):
        """Unset surface transparency

        :param id: surface id

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        """
        return self.UnsetSurfaceAttr(id, ATT_TRANSP)

    def UnsetSurfaceEmit(self, id):
        """Unset surface emission (currently unused)

        :param id: surface id

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        """
        return self.UnsetSurfaceAttr(id, ATT_EMIT)

    def UnsetSurfaceAttr(self, id, attr):
        """Unset surface attribute

        :param id: surface id
        :param attr: attribute descriptor

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        """
        if not GS_surf_exists(id):
            return -1

        Debug.msg(3, "Nviz::UnsetSurfaceAttr(): id=%d, attr=%d",
                  id, attr)

        ret = Nviz_unset_attr(id, MAP_OBJ_SURF, attr)

        if ret < 0:
            return -2

        return 1

    def SetSurfaceRes(self, id, fine, coarse):
        """Set surface resolution

        :param id: surface id
        :param fine: x/y fine resolution
        :param coarse: x/y coarse resolution

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        """
        Debug.msg(3, "Nviz::SetSurfaceRes(): id=%d, fine=%d, coarse=%d",
                  id, fine, coarse)

        if id > 0:
            if not GS_surf_exists(id):
                return -1

            if GS_set_drawres(id, fine, fine, coarse, coarse) < 0:
                return -2
        else:
            GS_setall_drawres(fine, fine, coarse, coarse)

        return 1

    def SetSurfaceStyle(self, id, style):
        """Set draw style

        Draw styles:
         - DM_GOURAUD
         - DM_FLAT
         - DM_FRINGE
         - DM_WIRE
         - DM_COL_WIRE
         - DM_POLY
         - DM_WIRE_POLY
         - DM_GRID_WIRE
         - DM_GRID_SURF

        :param id: surface id (<= 0 for all)
        :param style: draw style

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        """
        Debug.msg(3, "Nviz::SetSurfaceStyle(): id=%d, style=%d",
                  id, style)

        if id > 0:
            if not GS_surf_exists(id):
                return -1

            if GS_set_drawmode(id, style) < 0:
                return -2

            return 1

        if GS_setall_drawmode(style) < 0:
            return -2

        return 1

    def SetWireColor(self, id, color_str):
        """Set color of wire

        .. todo::
            all

        :param id: surface id (< 0 for all)
        :param color_str: color string (R:G:B)

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting attributes failed
        :return: 1 on success
        :return: 0 on failure
        """
        Debug.msg(3, "Nviz::SetWireColor(): id=%d, color=%s",
                  id, color_str)

        color = Nviz_color_from_str(color_str)

        if id > 0:
            if not GS_surf_exists(id):
                return -1

            GS_set_wire_color(id, color)
        else:
            nsurfs = c_int()
            surf_list = GS_get_surf_list(byref(nsurfs))
            for i in xrange(nsurfs.value):
                id = surf_list[i]
                GS_set_wire_color(id, color)

            G_free(surf_list)
            surf_list = None

        return 1

    def GetSurfacePosition(self, id):
        """Get surface position

        :param id: surface id

        :return: x,y,z
        :return: zero-length vector on error
        """
        if not GS_surf_exists(id):
            return []

        x, y, z = c_float(), c_float(), c_float()
        GS_get_trans(id, byref(x), byref(y), byref(z))

        Debug.msg(3, "Nviz::GetSurfacePosition(): id=%d, x=%f, y=%f, z=%f",
                  id, x.value, y.value, z.value)

        return [x.value, y.value, z.value]

    def SetSurfacePosition(self, id, x, y, z):
        """Set surface position

        :param id: surface id
        :param x,y,z: translation values

        :return: 1 on success
        :return: -1 surface not found
        :return: -2 setting position failed
        """
        if not GS_surf_exists(id):
            return -1

        Debug.msg(3, "Nviz::SetSurfacePosition(): id=%d, x=%f, y=%f, z=%f",
                  id, x, y, z)

        GS_set_trans(id, x, y, z)

        return 1

    def SetVectorLineMode(self, id, color_str, width, use_z):
        """Set mode of vector line overlay

        :param id: vector id
        :param color_str: color string
        :param width: line width
        :param use_z: display 3d or on surface

        :return: -1 vector set not found
        :return: -2 on failure
        :return: 1 on success
        """
        if not GV_vect_exists(id):
            return -1

        Debug.msg(
            3,
            "Nviz::SetVectorMode(): id=%d, color=%s, width=%d, use_z=%d",
            id,
            color_str,
            width,
            use_z)

        color = Nviz_color_from_str(color_str)

        # use memory by default
        if GV_set_style(id, 1, color, width, use_z) < 0:
            return -2

        return 1

    def SetVectorLineHeight(self, id, height):
        """Set vector height above surface (lines)

        :param id: vector set id
        :param height:

        :return: -1 vector set not found
        :return: 1 on success
        """
        if not GV_vect_exists(id):
            return -1

        Debug.msg(3, "Nviz::SetVectorLineHeight(): id=%d, height=%f",
                  id, height)

        GV_set_trans(id, 0.0, 0.0, height)

        return 1

    def SetVectorLineSurface(self, id, surf_id):
        """Set reference surface of vector set (lines)

        :param id: vector set id
        :param surf_id: surface id

        :return: 1 on success
        :return: -1 vector set not found
        :return: -2 surface not found
        :return: -3 on failure
        """
        if not GV_vect_exists(id):
            return -1

        if not GS_surf_exists(surf_id):
            return -2

        if GV_select_surf(id, surf_id) < 0:
            return -3

        return 1

    def UnsetVectorLineSurface(self, id, surf_id):
        """Unset reference surface of vector set (lines)

        :param id: vector set id
        :param surf_id: surface id

        :return: 1 on success
        :return: -1 vector set not found
        :return: -2 surface not found
        :return: -3 on failure
        """
        if not GV_vect_exists(id):
            return -1

        if not GS_surf_exists(surf_id):
            return -2

        if GV_unselect_surf(id, surf_id) < 0:
            return -3

        return 1

    def SetVectorPointMode(self, id, color_str, width, size, marker):
        """Set mode of vector point overlay

        :param id: vector id
        :param color_str: color string
        :param width: line width
        :param size: size of the symbol
        :param marker: type of the symbol

        :return: -1 vector set not found
        """
        if not GP_site_exists(id):
            return -1

        # dtree and ctree defined but not used
        if marker > 5:
            marker += 2

        Debug.msg(3, "Nviz::SetVectorPointMode(): id=%d, color=%s, "
                  "width=%d, size=%f, marker=%d",
                  id, color_str, width, size, marker)

        color = Nviz_color_from_str(color_str)

        if GP_set_style(id, color, width, size, marker) < 0:
            return -2

        return 1

    def SetVectorPointHeight(self, id, height):
        """Set vector height above surface (points)

        :param id: vector set id
        :param height:

        :return: -1 vector set not found
        :return: 1 on success
        """
        if not GP_site_exists(id):
            return -1

        Debug.msg(3, "Nviz::SetVectorPointHeight(): id=%d, height=%f",
                  id, height)

        GP_set_trans(id, 0.0, 0.0, height)

        return 1

    def SetVectorPointSurface(self, id, surf_id):
        """Set reference surface of vector set (points)

        :param id: vector set id
        :param surf_id: surface id

        :return: 1 on success
        :return: -1 vector set not found
        :return: -2 surface not found
        :return: -3 on failure
        """
        if not GP_site_exists(id):
            return -1

        if not GS_surf_exists(surf_id):
            return -2

        if GP_select_surf(id, surf_id) < 0:
            return -3

        return 1

    def ReadVectorColors(self, name, mapset):
        """Read vector colors

        :param name: vector map name
        :param mapset: mapset name (empty string (\c "") for search path)

        :return: -1 on error
        :return: 0 if color table missing
        :return: 1 on success (color table found)
        """
        return Vect_read_colors(name, mapset, self.color)

    def CheckColorTable(self, id, type):
        """Check if color table exists.

        :param id: vector set id
        :param type: vector set type (lines/points)

        :return: 1 color table exists
        :return: 0 no color table found
        :return: -1 on error
        :return: -2 vector set not found
        """
        file = c_char_p()

        if type == 'points':
            ret = GP_get_sitename(id, byref(file))
        elif type == 'lines':
            ret = GV_get_vectname(id, byref(file))

        if ret < 0:
            return -2

        return self.ReadVectorColors(file, "")

    def SetPointsStyleThematic(self, id, layer, color=None, colorTable=False,
                               width=None, size=None, symbol=None):
        """Set thematic style for vector points

        :param id: vector set id
        :param layer: layer number for thematic mapping
        :param colorTable: use color table
        :param color: color column name
        :param width: width column name
        :param size: size column name
        :param symbol: symbol column name
        """
        file = c_char_p()
        ret = GP_get_sitename(id, byref(file))
        if ret < 0:
            return -1

        ret = self.ReadVectorColors(file, "")
        if ret < 0:
            return -1

        if colorTable:
            GP_set_style_thematic(
                id, layer, color, width, size, symbol, self.color)
        else:
            GP_set_style_thematic(id, layer, color, width, size, symbol, None)

    def SetLinesStyleThematic(
            self, id, layer, color=None, colorTable=False, width=None):
        """Set thematic style for vector lines

        :param id: vector set id
        :param layer: layer number for thematic mapping
        :param color: color column name
        :param colorTable: use color table
        :param width: width column name
        """
        file = c_char_p()
        ret = GV_get_vectname(id, byref(file))
        if ret < 0:
            return -1

        ret = self.ReadVectorColors(file, "")
        if ret < 0:
            return -1

        if colorTable:
            GV_set_style_thematic(id, layer, color, width, self.color)
        else:
            GV_set_style_thematic(id, layer, color, width, None)

    def UnsetLinesStyleThematic(self, id):
        """Unset thematic style for vector points"""
        GV_unset_style_thematic(id)

    def UnsetPointsStyleThematic(self, id):
        """Unset thematic style for vector lines"""
        GP_unset_style_thematic(id)

    def UnsetVectorPointSurface(self, id, surf_id):
        """Unset reference surface of vector set (points)

        :param id: vector set id
        :param surf_id: surface id

        :return: 1 on success
        :return: -1 vector set not found
        :return: -2 surface not found
        :return: -3 on failure
        """
        if not GP_site_exists(id):
            return -1

        if not GS_surf_exists(surf_id):
            return -2

        if GP_unselect_surf(id, surf_id) < 0:
            return -3

        return 1

    def SetVectorPointZMode(self, id, zMode):
        """Set z mode (use z coordinate or not)

        :param id: volume id
        :param zMode: bool

        :return: -1 on failure
        :return: 0 when no 3d
        :return: 1 on success
        """
        if not GP_site_exists(id):
            return -1

        return GP_set_zmode(id, int(zMode))

    def AddIsosurface(self, id, level, isosurf_id=None):
        """Add new isosurface

        :param id: volume id
        :param level: isosurface level (topography)
        :param isosurf_id: isosurface id

        :return: -1 on failure
        :return: 1 on success
        """
        if not GVL_vol_exists(id):
            return -1

        if isosurf_id is not None:
            num = GVL_isosurf_num_isosurfs(id)
            if num < 0 or isosurf_id != num:
                return -1

        if GVL_isosurf_add(id) < 0:
            return -1

        # set topography level
        nisosurfs = GVL_isosurf_num_isosurfs(id)

        return GVL_isosurf_set_att_const(id, nisosurfs - 1, ATT_TOPO, level)

    def AddSlice(self, id, slice_id=None):
        """Add new slice

        :param id: volume id
        :param slice_id: slice id

        :return: -1 on failure
        :return: number of slices
        """
        if not GVL_vol_exists(id):
            return -1

        if slice_id is not None:
            num = GVL_slice_num_slices(id)
            if num < 0 or slice_id != num:
                return -1

        if GVL_slice_add(id) < 0:
            return -1

        return GVL_slice_num_slices(id)

    def DeleteIsosurface(self, id, isosurf_id):
        """Delete isosurface

        :param id: volume id
        :param isosurf_id: isosurface id

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 isosurface not found
        :return: -3 on failure
        """
        if not GVL_vol_exists(id):
            return -1

        if isosurf_id > GVL_isosurf_num_isosurfs(id):
            return -2

        ret = GVL_isosurf_del(id, isosurf_id)

        if ret < 0:
            return -3

        return 1

    def DeleteSlice(self, id, slice_id):
        """Delete slice

        :param id: volume id
        :param slice_id: slice id

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 slice not found
        :return: -3 on failure
        """
        if not GVL_vol_exists(id):
            return -1

        if slice_id > GVL_slice_num_slices(id):
            return -2

        ret = GVL_slice_del(id, slice_id)

        if ret < 0:
            return -3

        return 1

    def MoveIsosurface(self, id, isosurf_id, up):
        """Move isosurface up/down in the list

        :param id: volume id
        :param isosurf_id: isosurface id
        :param up: if true move up otherwise down

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 isosurface not found
        :return: -3 on failure
        """
        if not GVL_vol_exists(id):
            return -1

        if isosurf_id > GVL_isosurf_num_isosurfs(id):
            return -2

        if up:
            ret = GVL_isosurf_move_up(id, isosurf_id)
        else:
            ret = GVL_isosurf_move_down(id, isosurf_id)

        if ret < 0:
            return -3

        return 1

    def MoveSlice(self, id, slice_id, up):
        """Move slice up/down in the list

        :param id: volume id
        :param slice_id: slice id
        :param up: if true move up otherwise down

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 slice not found
        :return: -3 on failure
        """
        if not GVL_vol_exists(id):
            return -1

        if slice_id > GVL_slice_num_slices(id):
            return -2

        if up:
            ret = GVL_slice_move_up(id, slice_id)
        else:
            ret = GVL_slice_move_down(id, slice_id)

        if ret < 0:
            return -3

        return 1

    def SetIsosurfaceTopo(self, id, isosurf_id, map, value):
        """Set isosurface level

        :param id: volume id
        :param isosurf_id: isosurface id (0 - MAX_ISOSURFS)
        :param map: if true use map otherwise constant
        :param value: map name of value

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 isosurface not found
        :return: -3 on failure
        """
        return self.SetIsosurfaceAttr(id, isosurf_id, ATT_TOPO, map, value)

    def SetIsosurfaceColor(self, id, isosurf_id, map, value):
        """Set isosurface color

        :param id: volume id
        :param isosurf_id: isosurface id (0 - MAX_ISOSURFS)
        :param map: if true use map otherwise constant
        :param value: map name of value

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 isosurface not found
        :return: -3 on failure
        """
        return self.SetIsosurfaceAttr(id, isosurf_id, ATT_COLOR, map, value)

    def SetIsosurfaceMask(self, id, isosurf_id, invert, value):
        """Set isosurface mask

        .. todo::
            invert

        :param id: volume id
        :param isosurf_id: isosurface id (0 - MAX_ISOSURFS)
        :param invert: true for invert mask
        :param value: map name to be used for mask

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 isosurface not found
        :return: -3 on failure
        """
        return self.SetIsosurfaceAttr(id, isosurf_id, ATT_MASK, True, value)

    def SetIsosurfaceTransp(self, id, isosurf_id, map, value):
        """Set isosurface transparency

        :param id: volume id
        :param isosurf_id: isosurface id (0 - MAX_ISOSURFS)
        :param map: if true use map otherwise constant
        :param value: map name of value

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 isosurface not found
        :return: -3 on failure
        """
        return self.SetIsosurfaceAttr(id, isosurf_id, ATT_TRANSP, map, value)

    def SetIsosurfaceShine(self, id, isosurf_id, map, value):
        """Set isosurface shininess

        :param id: volume id
        :param isosurf_id: isosurface id (0 - MAX_ISOSURFS)
        :param map: if true use map otherwise constant
        :param value: map name of value

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 isosurface not found
        :return: -3 on failure
        """
        return self.SetIsosurfaceAttr(id, isosurf_id, ATT_SHINE, map, value)

    def SetIsosurfaceEmit(self, id, isosurf_id, map, value):
        """Set isosurface emission (currently unused)

        :param id: volume id
        :param isosurf_id: isosurface id (0 - MAX_ISOSURFS)
        :param map: if true use map otherwise constant
        :param value: map name of value

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 isosurface not found
        :return: -3 on failure
        """
        return self.SetIsosurfaceAttr(id, isosurf_id, ATT_EMIT, map, value)

    def SetIsosurfaceAttr(self, id, isosurf_id, attr, map, value):
        """Set isosurface attribute

        :param id: volume id
        :param isosurf_id: isosurface id (0 - MAX_ISOSURFS)
        :param attr: attribute desc
        :param map: if true use map otherwise constant
        :param value: map name of value

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 isosurface not found
        :return: -3 setting attributes failed
        """
        if not GVL_vol_exists(id):
            return -1

        if isosurf_id > GVL_isosurf_num_isosurfs(id) - 1:
            return -2

        if map:
            ret = GVL_isosurf_set_att_map(id, isosurf_id, attr, value)
        else:
            if attr == ATT_COLOR:
                val = Nviz_color_from_str(value)
            else:
                val = float(value)

            ret = GVL_isosurf_set_att_const(id, isosurf_id, attr, val)

        Debug.msg(3, "Nviz::SetIsosurfaceAttr(): id=%d, isosurf=%d, "
                  "attr=%d, map=%s, value=%s",
                  id, isosurf_id, attr, map, value)

        if ret < 0:
            return -2

        return 1

    def UnsetIsosurfaceMask(self, id, isosurf_id):
        """Unset isosurface mask

        :param id: volume id
        :param isosurf_id: isosurface id (0 - MAX_ISOSURFS)

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 isosurface not found
        :return: -3 setting attributes failed
        """
        return self.UnsetIsosurfaceAttr(id, isosurf_id, ATT_MASK)

    def UnsetIsosurfaceTransp(self, id, isosurf_id):
        """Unset isosurface transparency

        :param id: volume id
        :param isosurf_id: isosurface id (0 - MAX_ISOSURFS)

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 isosurface not found
        :return: -3 setting attributes failed
        """
        return self.UnsetIsosurfaceAttr(id, isosurf_id, ATT_TRANSP)

    def UnsetIsosurfaceEmit(self, id, isosurf_id):
        """Unset isosurface emission (currently unused)

        :param id: volume id
        :param isosurf_id: isosurface id (0 - MAX_ISOSURFS)

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 isosurface not found
        :return: -3 setting attributes failed
        """
        return self.UnsetIsosurfaceAttr(id, isosurf_id, ATT_EMIT)

    def UnsetIsosurfaceAttr(self, id, isosurf_id, attr):
        """Unset surface attribute

        :param id: surface id
        :param isosurf_id: isosurface id (0 - MAX_ISOSURFS)
        :param attr: attribute descriptor

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 isosurface not found
        :return: -2 on failure
        """
        if not GVL_vol_exists(id):
            return -1

        if isosurf_id > GVL_isosurf_num_isosurfs(id) - 1:
            return -2

        Debug.msg(3, "Nviz::UnsetSurfaceAttr(): id=%d, isosurf_id=%d, attr=%d",
                  id, isosurf_id, attr)

        ret = GVL_isosurf_unset_att(id, isosurf_id, attr)

        if ret < 0:
            return -2

        return 1

    def SetIsosurfaceMode(self, id, mode):
        """Set draw mode for isosurfaces

        :param id: isosurface id
        :param mode: isosurface draw mode

        :return: 1 on success
        :return: -1 volume set not found
        :return: -2 on failure
        """
        if not GVL_vol_exists(id):
            return -1

        ret = GVL_isosurf_set_drawmode(id, mode)

        if ret < 0:
            return -2

        return 1

    def SetSliceMode(self, id, mode):
        """Set draw mode for slices

        :param id: slice id
        :param mode: slice draw mode

        :return: 1 on success
        :return: -1 volume set not found
        :return: -2 on failure
        """
        if not GVL_vol_exists(id):
            return -1

        ret = GVL_slice_set_drawmode(id, mode)

        if ret < 0:
            return -2

        return 1

    def SetIsosurfaceRes(self, id, res):
        """Set draw resolution for isosurfaces

        :param id: isosurface id
        :param res: resolution value

        :return: 1 on success
        :return: -1 volume set not found
        :return: -2 on failure
        """
        if not GVL_vol_exists(id):
            return -1

        ret = GVL_isosurf_set_drawres(id, res, res, res)

        if ret < 0:
            return -2

        return 1

    def SetSliceRes(self, id, res):
        """Set draw resolution for slices

        :param id: slice id
        :param res: resolution value

        :return: 1 on success
        :return: -1 volume set not found
        :return: -2 on failure
        """
        if not GVL_vol_exists(id):
            return -1

        ret = GVL_slice_set_drawres(id, res, res, res)

        if ret < 0:
            return -2

        return 1

    def SetSlicePosition(self, id, slice_id, x1, x2, y1, y2, z1, z2, dir):
        """Set slice position

        :param id: volume id
        :param slice_id: slice id
        :param x1,x2,y1,y2,z1,z2: slice coordinates
        :param dir: axis

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 slice not found
        :return: -3 on failure
        """
        if not GVL_vol_exists(id):
            return -1

        if slice_id > GVL_slice_num_slices(id):
            return -2

        ret = GVL_slice_set_pos(id, slice_id, x1, x2, y1, y2, z1, z2, dir)

        if ret < 0:
            return -2

        return 1

    def SetSliceTransp(self, id, slice_id, value):
        """Set slice transparency

        :param id: volume id
        :param slice_id: slice id
        :param value: transparency value (0 - 255)

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 slice not found
        :return: -3 on failure
        """

        if not GVL_vol_exists(id):
            return -1

        if slice_id > GVL_slice_num_slices(id):
            return -2

        ret = GVL_slice_set_transp(id, slice_id, value)

        if ret < 0:
            return -2

        return 1

    def SetIsosurfaceInOut(self, id, isosurf_id, inout):
        """Set inout mode

        :param id: volume id
        :param isosurf_id: isosurface id
        :param inout: mode true/false

        :return: 1 on success
        :return: -1 volume set not found
        :return: -2 isosurface not found
        :return: -3 on failure
        """
        if not GVL_vol_exists(id):
            return -1

        if isosurf_id > GVL_isosurf_num_isosurfs(id) - 1:
            return -2

        ret = GVL_isosurf_set_flags(id, isosurf_id, inout)

        if ret < 0:
            return -3

        return 1

    def GetVolumePosition(self, id):
        """Get volume position

        :param id: volume id

        :return: x,y,z
        :return: zero-length vector on error
        """
        if not GVL_vol_exists(id):
            return []

        x, y, z = c_float(), c_float(), c_float()
        GVL_get_trans(id, byref(x), byref(y), byref(z))

        Debug.msg(3, "Nviz::GetVolumePosition(): id=%d, x=%f, y=%f, z=%f",
                  id, x.value, y.value, z.value)

        return [x.value, y.value, z.value]

    def SetVolumePosition(self, id, x, y, z):
        """Set volume position

        :param id: volume id
        :param x,y,z: translation values

        :return: 1 on success
        :return: -1 volume not found
        :return: -2 setting position failed
        """
        if not GVL_vol_exists(id):
            return -1

        Debug.msg(3, "Nviz::SetVolumePosition(): id=%d, x=%f, y=%f, z=%f",
                  id, x, y, z)

        GVL_set_trans(id, x, y, z)

        return 1

    def SetVolumeDrawBox(self, id, ifBox):
        """Display volume wire box

        :param id: volume id
        :param ifBox: True to draw wire box, False otherwise
        :type ifBox: bool
        :return: 1 on success
        :return: -1 volume not found
        """
        if not GVL_vol_exists(id):
            return -1

        Debug.msg(3, "Nviz::SetVolumeDrawBox(): id=%d, ifBox=%d", id, ifBox)

        GVL_set_draw_wire(id, int(ifBox))

        return 1

    def GetCPlaneCurrent(self):
        return Nviz_get_current_cplane(self.data)

    def GetCPlanesCount(self):
        """Returns number of cutting planes"""
        return Nviz_num_cplanes(self.data)

    def GetCPlaneRotation(self):
        """Returns rotation parameters of current cutting plane"""
        x, y, z = c_float(), c_float(), c_float()

        current = Nviz_get_current_cplane(self.data)
        Nviz_get_cplane_rotation(
            self.data,
            current,
            byref(x),
            byref(y),
            byref(z))

        return x.value, y.value, z.value

    def GetCPlaneTranslation(self):
        """Returns translation parameters of current cutting plane"""
        x, y, z = c_float(), c_float(), c_float()

        current = Nviz_get_current_cplane(self.data)
        Nviz_get_cplane_translation(
            self.data, current, byref(x), byref(y), byref(z))

        return x.value, y.value, z.value

    def SetCPlaneRotation(self, x, y, z):
        """Set current clip plane rotation

        :param x,y,z: rotation parameters
        """
        current = Nviz_get_current_cplane(self.data)
        Nviz_set_cplane_rotation(self.data, current, x, y, z)
        Nviz_draw_cplane(self.data, -1, -1)

    def SetCPlaneTranslation(self, x, y, z):
        """Set current clip plane translation

        :param x,y,z: translation parameters
        """
        current = Nviz_get_current_cplane(self.data)
        Nviz_set_cplane_translation(self.data, current, x, y, z)
        Nviz_draw_cplane(self.data, -1, -1)
        Debug.msg(3, "Nviz::SetCPlaneTranslation(): id=%d, x=%f, y=%f, z=%f",
                  current, x, y, z)

    def SetCPlaneInteractively(self, x, y):
        current = Nviz_get_current_cplane(self.data)
        ret = Nviz_set_cplane_here(self.data, current, x, y)
        if ret:
            Nviz_draw_cplane(self.data, -1, -1)
            x, y, z = self.GetCPlaneTranslation()
            return x, y, z
        else:
            return None, None, None

    def SelectCPlane(self, index):
        """Select cutting plane

        :param index: index of cutting plane
        """
        Nviz_on_cplane(self.data, index)

    def UnselectCPlane(self, index):
        """Unselect cutting plane

        :param index: index of cutting plane
        """
        Nviz_off_cplane(self.data, index)

    def SetFenceColor(self, index):
        """Select current cutting plane

        :param index: type of fence - from 0 (off) to 4
        """
        Nviz_set_fence_color(self.data, index)

    def GetXYRange(self):
        """Get xy range"""
        return Nviz_get_xyrange(self.data)

    def GetZRange(self):
        """Get z range"""
        min, max = c_float(), c_float()
        Nviz_get_zrange(self.data, byref(min), byref(max))
        return min.value, max.value

    def SaveToFile(self, filename, width=20, height=20, itype='ppm'):
        """Save current GL screen to ppm/tif file

        :param filename: file name
        :param width: image width
        :param height: image height
        :param itype: image type ('ppm' or 'tif')
        """
        widthOrig = self.width
        heightOrig = self.height

        self.ResizeWindow(width, height)
        GS_clear(Nviz_get_bgcolor(self.data))
        self.Draw(False, -1)
        if itype == 'ppm':
            GS_write_ppm(filename)
        else:
            GS_write_tif(filename)

        self.ResizeWindow(widthOrig, heightOrig)

    def DrawLightingModel(self):
        """Draw lighting model"""
        if self.showLight:
            Nviz_draw_model(self.data)

    def DrawFringe(self):
        """Draw fringe"""
        Nviz_draw_fringe(self.data)

    def SetFringe(self, sid, color, elev, nw=False,
                  ne=False, sw=False, se=False):
        """Set fringe

        :param sid: surface id
        :param color: color
        :param elev: elevation (height)
        :param nw,ne,sw,se: fringe edges (turn on/off)
        """
        scolor = str(color[0]) + ':' + str(color[1]) + ':' + str(color[2])
        Nviz_set_fringe(self.data,
                        sid, Nviz_color_from_str(scolor),
                        elev, int(nw), int(ne), int(sw), int(se))

    def DrawArrow(self):
        """Draw north arrow
        """
        return Nviz_draw_arrow(self.data)

    def SetArrow(self, sx, sy, size, color):
        """Set north arrow from canvas coordinates

        :param sx,sy: canvas coordinates
        :param size: arrow length
        :param color: arrow color
        """
        return Nviz_set_arrow(self.data, sx, sy, size,
                              Nviz_color_from_str(color))

    def DeleteArrow(self):
        """Delete north arrow
        """
        Nviz_delete_arrow(self.data)

    def SetScalebar(self, id, sx, sy, size, color):
        """Set scale bar from canvas coordinates

        :param sx,sy: canvas coordinates
        :param id: scale bar id
        :param size: scale bar length
        :param color: scale bar color
        """
        return Nviz_set_scalebar(
            self.data, id, sx, sy, size, Nviz_color_from_str(color))

    def DrawScalebar(self):
        """Draw scale bar
        """
        return Nviz_draw_scalebar(self.data)

    def DeleteScalebar(self, id):
        """Delete scalebar
        """
        Nviz_delete_scalebar(self.data, id)

    def GetPointOnSurface(self, sx, sy):
        """Get point on surface

        :param sx,sy: canvas coordinates (LL)
        """
        sid = c_int()
        x = c_float()
        y = c_float()
        z = c_float()
        Debug.msg(5, "Nviz::GetPointOnSurface(): sx=%d sy=%d" % (sx, sy))
        num = GS_get_selected_point_on_surface(
            sx, sy, byref(sid), byref(x), byref(y), byref(z))
        if num == 0:
            return (None, None, None, None)

        return (sid.value, x.value, y.value, z.value)

    def QueryMap(self, sx, sy):
        """Query surface map

        :param sx,sy: canvas coordinates (LL)
        """
        sid, x, y, z = self.GetPointOnSurface(sx, sy)
        if not sid:
            return None

        catstr = create_string_buffer(256)
        valstr = create_string_buffer(256)
        GS_get_cat_at_xy(sid, ATT_TOPO, catstr, x, y)
        GS_get_val_at_xy(sid, ATT_COLOR, valstr, x, y)

        return {'id': sid,
                'x': x,
                'y': y,
                'z': z,
                'elevation': catstr.value.replace('(', '').replace(')', ''),
                'color': valstr.value}

    def GetDistanceAlongSurface(self, sid, p1, p2, useExag=True):
        """Get distance measured along surface"""
        d = c_float()

        GS_get_distance_alongsurf(sid, p1[0], p1[1], p2[0], p2[1],
                                  byref(d), int(useExag))

        return d.value

    def GetRotationParameters(self, dx, dy):
        """Get rotation parameters (angle, x, y, z axes)

        :param dx,dy: difference from previous mouse drag event
        """
        modelview = (c_double * 16)()
        Nviz_get_modelview(byref(modelview))

        angle = sqrt(dx * dx + dy * dy) / float(self.width + 1) * 180.0
        m = []
        row = []
        for i, item in enumerate(modelview):
            row.append(item)
            if (i + 1) % 4 == 0:
                m.append(row)
                row = []
        inv = matrix(m).I
        ax, ay, az = dy, dx, 0.
        x = inv[0, 0] * ax + inv[1, 0] * ay + inv[2, 0] * az
        y = inv[0, 1] * ax + inv[1, 1] * ay + inv[2, 1] * az
        z = inv[0, 2] * ax + inv[1, 2] * ay + inv[2, 2] * az

        return angle, x, y, z

    def Rotate(self, angle, x, y, z):
        """Set rotation parameters
        Rotate scene (difference from current state).

        :param angle: angle
        :param x,y,z: axis coordinate
        """
        Nviz_set_rotation(angle, x, y, z)

    def UnsetRotation(self):
        """Stop rotating the scene"""
        Nviz_unset_rotation()

    def ResetRotation(self):
        """Reset scene rotation"""
        Nviz_init_rotation()

    def GetRotationMatrix(self):
        """Get rotation matrix"""
        matrix = (c_double * 16)()
        GS_get_rotation_matrix(byref(matrix))
        returnMatrix = []
        for item in matrix:
            returnMatrix.append(item)
        return returnMatrix

    def SetRotationMatrix(self, matrix):
        """Set rotation matrix"""
        mtrx = (c_double * 16)()
        for i in range(len(matrix)):
            mtrx[i] = matrix[i]
        GS_set_rotation_matrix(byref(mtrx))

    def Start2D(self):
        Nviz_set_2D(self.width, self.height)

    def FlyThrough(self, flyInfo, mode, exagInfo):
        """Fly through the scene

        :param flyInfo: fly parameters
        :param mode: 0 or 1 for different fly behaviour
        :param exagInfo: parameters changing fly speed
        """
        fly = (c_float * 3)()
        for i, item in enumerate(flyInfo):
            fly[i] = item
        exag = (c_int * 2)()
        exag[0] = int(exagInfo['move'])
        exag[1] = int(exagInfo['turn'])
        Nviz_flythrough(self.data, fly, exag, mode)


class Texture(object):
    """Class representing OpenGL texture"""

    def __init__(self, filepath, overlayId, coords):
        """Load image to texture

        :param filepath: path to image file
        :param overlayId: id of overlay (1 for legend, 101 and more for text)
        :param coords: image coordinates
        """
        self.path = filepath
        self.image = autoCropImageFromFile(filepath)
        self.width = self.orig_width = self.image.GetWidth()
        self.height = self.orig_height = self.image.GetHeight()
        self.id = overlayId
        self.coords = coords
        self.active = True

        # alpha needs to be initialized
        if not self.image.HasAlpha():
            self.image.InitAlpha()

        # resize image to match 2^n
        self.Resize()

        # check max texture size
        maxSize = c_int()
        Nviz_get_max_texture(byref(maxSize))
        self.maxSize = maxSize.value
        if self.maxSize < self.width or self.maxSize < self.height:
            # TODO: split up image
            self.textureId = None
        else:
            self.textureId = self.Load()

    def __del__(self):
        """Delete texture"""
        if self.textureId:
            Nviz_del_texture(self.textureId)
        grass.try_remove(self.path)

    def Resize(self):
        """Resize image to match 2^n"""
        n = m = 1
        while self.width > pow(2, n):
            n += 1
        while self.height > pow(2, m):
            m += 1
        self.image.Resize(size=(pow(2, n), pow(2, m)), pos=(0, 0))
        self.width = self.image.GetWidth()
        self.height = self.image.GetHeight()

    def Load(self):
        """Load image to texture"""
        if self.image.HasAlpha():
            bytesPerPixel = 4
        else:
            bytesPerPixel = 3
        bytes = bytesPerPixel * self.width * self.height
        rev_val = self.height - 1
        im = (c_ubyte * bytes)()
        bytes3 = 3 * self.width * self.height
        bytes1 = self.width * self.height
        imageData = struct.unpack(str(bytes3) + 'B', self.image.GetData())
        if self.image.HasAlpha():
            alphaData = struct.unpack(
                str(bytes1) + 'B', self.image.GetAlphaData())

        # this takes too much time
        wx.BeginBusyCursor()
        for i in range(self.height):
            for j in range(self.width):
                im[(j + i * self.width) * bytesPerPixel + 0] = imageData[(j +
                                                                          (rev_val - i) * self.width) * 3 + 0]
                im[(j + i * self.width) * bytesPerPixel + 1] = imageData[(j +
                                                                          (rev_val - i) * self.width) * 3 + 1]
                im[(j + i * self.width) * bytesPerPixel + 2] = imageData[(j +
                                                                          (rev_val - i) * self.width) * 3 + 2]
                if self.image.HasAlpha():
                    im[(j + i * self.width) * bytesPerPixel + 3] = alphaData[(j +
                                                                              (rev_val - i) * self.width)]
        wx.EndBusyCursor()

        id = Nviz_load_image(
            im,
            self.width,
            self.height,
            self.image.HasAlpha())

        return id

    def Draw(self):
        """Draw texture as an image"""
        Nviz_draw_image(
            self.coords[0],
            self.coords[1],
            self.width,
            self.height,
            self.textureId)

    def HitTest(self, x, y, radius):
        copy = wx.Rect(self.coords[0], self.coords[1], self.orig_width, self.orig_height)
        copy.Inflate(radius, radius)
        return copy.ContainsXY(x, y)

    def MoveTexture(self, dx, dy):
        """Move texture on the screen"""
        self.coords[0] += dx
        self.coords[1] += dy

    def SetCoords(self, coords):
        """Set coordinates"""
        dx = coords[0] - self.coords[0]
        dy = coords[1] - self.coords[1]
        self.MoveTexture(dx, dy)

    def GetId(self):
        """Returns image id."""
        return self.id

    def SetActive(self, active=True):
        self.active = active

    def IsActive(self):
        return self.active


class ImageTexture(Texture):
    """Class representing OpenGL texture as an overlay image"""

    def __init__(self, filepath, overlayId, coords, cmd):
        """Load image to texture

        :param filepath: path to image file
        :param overlayId: id of overlay (1 for legend)
        :param coords: image coordinates
        :param cmd: d.legend command
        """
        Texture.__init__(
            self,
            filepath=filepath,
            overlayId=overlayId,
            coords=coords)

        self.cmd = cmd

    def GetCmd(self):
        """Returns overlay command."""
        return self.cmd

    def Corresponds(self, item):
        return sorted(self.GetCmd()) == sorted(item.GetCmd())