2
* \file grid-snapper.cpp
3
* \brief Snapping things to grids.
6
* Lauris Kaplinski <lauris@kaplinski.com>
7
* Frank Felfe <innerspace@iname.com>
8
* Carl Hetherington <inkscape@carlh.net>
10
* Copyright (C) 1999-2002 Authors
12
* Released under GNU GPL, read the file 'COPYING' for more information
15
#include "sp-namedview.h"
16
#include "display/canvas-grid.h"
19
* \return x rounded to the nearest multiple of c1 plus c0.
22
* If c1==0 (and c0 is finite), then returns +/-inf. This makes grid spacing of zero
23
* mean "ignore the grid in this dimention". We're currently discussing "good" semantics
24
* for guide/grid snapping.
27
/* FIXME: move this somewhere else, perhaps */
28
static double round_to_nearest_multiple_plus(double x, double const c1, double const c0)
30
return floor((x - c0) / c1 + .5) * c1 + c0;
33
Inkscape::GridSnapper::GridSnapper(SPNamedView const *nv, NR::Coord const d) : LineSnapper(nv, d)
38
Inkscape::LineSnapper::LineList Inkscape::GridSnapper::_getSnapLines(NR::Point const &p) const
42
SPCGrid *griditem = NULL;
43
for (GSList *l = _named_view->gridviews; l != NULL; l = l->next) {
44
// FIXME : this is a hack since there is only one view for now
45
// but when we'll handle multiple views, snapping should
46
// must be rethought and maybe only the current view
47
// should give back it's SHOWN lines to snap to
48
// For now, the last SPCGrid in _named_view->gridviews will be used.
49
griditem = SP_CGRID(l->data);
52
g_assert(griditem != NULL);
54
for (unsigned int i = 0; i < 2; ++i) {
56
/* This is to make sure we snap to only visible grid lines */
57
double const scale = griditem->scaled[i] ? griditem->empspacing : 1;
59
NR::Coord const rounded = round_to_nearest_multiple_plus(p[i],
60
_named_view->gridspacing[i] * scale,
61
_named_view->gridorigin[i]);
63
s.push_back(std::make_pair(NR::Dim2(i), rounded));
72
c-file-style:"stroustrup"
73
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
78
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :