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livetrax/libs/canvas/arrow.cc

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/*
Copyright (C) 2011 Paul Davis
Author: Carl Hetherington <cth@carlh.net>
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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/** @file canvas/arrow.cc
* @brief Implementation of the Arrow canvas object.
*/
#include "pbd/compose.h"
#include "canvas/arrow.h"
#include "canvas/debug.h"
#include "canvas/polygon.h"
#include "canvas/line.h"
using namespace ArdourCanvas;
/** Construct an Arrow.
* @param parent Parent canvas group.
*/
Arrow::Arrow (Canvas* c)
: Container (c)
{
setup ();
}
Arrow::Arrow (Item* parent)
: Container (parent)
{
setup ();
}
void
Arrow::setup ()
{
/* set up default arrow heads at each end */
for (int i = 0; i < 2; ++i) {
_heads[i].polygon = new Polygon (this);
_heads[i].outward = true;
_heads[i].width = 4;
_heads[i].height = 4;
setup_polygon (i);
CANVAS_DEBUG_NAME (_heads[i].polygon, string_compose ("arrow head %1", i));
}
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_line = new Line (this);
CANVAS_DEBUG_NAME (_line, "arrow line");
}
void
Arrow::compute_bounding_box () const
{
/* Compute our bounding box manually rather than using the default
container algorithm, since having the bounding box with origin other
than zero causes strange problems for mysterious reasons. */
const double outline_pad = 0.5 + (_line->outline_width() / 2.0);
const double head_width = std::max(_heads[0].width, _heads[1].width);
_bounding_box = Rect(0,
0,
_line->x1() + (head_width / 2.0) + outline_pad,
_line->y1());
_bounding_box_dirty = false;
}
/** Set whether to show an arrow head at one end or other
* of the line.
* @param which 0 or 1 to specify the arrow head to set up.
* @param true if this arrow head should be shown.
*/
void
Arrow::set_show_head (int which, bool show)
{
assert (which == 0 || which == 1);
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begin_change ();
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if (!show) {
delete _heads[which].polygon;
_heads[which].polygon = 0;
} else {
setup_polygon (which);
}
_bounding_box_dirty = true;
end_change ();
}
/** Set whether a given arrow head points into the line or
* away from it.
* @param which 0 or 1 to specify the arrow head to set up.
* @param true if this arrow head should point out from the line,
* otherwise false to point in.
*/
void
Arrow::set_head_outward (int which, bool outward)
{
assert (which == 0 || which == 1);
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begin_change ();
_heads[which].outward = outward;
setup_polygon (which);
_bounding_box_dirty = true;
end_change ();
}
/** Set the height of a given arrow head.
* @param which 0 or 1 to specify the arrow head to set up.
* @param height Height of the arrow head in pixels.
*/
void
Arrow::set_head_height (int which, Distance height)
{
assert (which == 0 || which == 1);
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begin_change ();
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_heads[which].height = height;
setup_polygon (which);
_bounding_box_dirty = true;
end_change ();
}
/** Set the width of a given arrow head.
* @param which 0 or 1 to specify the arrow head to set up.
* @param width Width of the arrow head in pixels.
*/
void
Arrow::set_head_width (int which, Distance width)
{
assert (which == 0 || which == 1);
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begin_change ();
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_heads[which].width = width;
setup_polygon (which);
_bounding_box_dirty = true;
end_change ();
}
/** Set the width of our line, and the outline of our arrow(s).
* @param width New width in pixels.
*/
void
Arrow::set_outline_width (Distance width)
{
_line->set_outline_width (width);
if (_heads[0].polygon) {
_heads[0].polygon->set_outline_width (width);
}
if (_heads[1].polygon) {
_heads[1].polygon->set_outline_width (width);
}
_bounding_box_dirty = true;
}
/** Set the x position of our line.
* @param x New x position in pixels (in our coordinate system).
*/
void
Arrow::set_x (Coord x)
{
_line->set_x0 (x);
_line->set_x1 (x);
for (int i = 0; i < 2; ++i) {
if (_heads[i].polygon) {
_heads[i].polygon->set_x_position (x - _heads[i].width / 2);
}
}
_bounding_box_dirty = true;
}
/** Set the y position of end 0 of our line.
* @param y0 New y0 position in pixels (in our coordinate system).
*/
void
Arrow::set_y0 (Coord y0)
{
_line->set_y0 (y0);
if (_heads[0].polygon) {
_heads[0].polygon->set_y_position (y0);
}
_bounding_box_dirty = true;
}
/** Set the y position of end 1 of our line.
* @param y1 New y1 position in pixels (in our coordinate system).
*/
void
Arrow::set_y1 (Coord y1)
{
_line->set_y1 (y1);
if (_heads[1].polygon) {
_heads[1].polygon->set_y_position (y1 - _heads[1].height);
}
_bounding_box_dirty = true;
}
/** @return x position of our line in pixels (in our coordinate system) */
Coord
Arrow::x () const
{
return _line->x0 ();
}
/** @return y position of end 1 of our line in pixels (in our coordinate system) */
Coord
Arrow::y1 () const
{
return _line->y1 ();
}
/** Set up the polygon used to represent a particular arrow head.
* @param which 0 or 1 to specify the arrow head to set up.
*/
void
Arrow::setup_polygon (int which)
{
assert (which == 0 || which == 1);
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Points points;
if ((which == 0 && _heads[which].outward) || (which == 1 && !_heads[which].outward)) {
/* this is an arrow head pointing towards -ve y */
points.push_back (Duple (_heads[which].width / 2, 0));
points.push_back (Duple (_heads[which].width, _heads[which].height));
points.push_back (Duple (0, _heads[which].height));
} else {
/* this is an arrow head pointing towards +ve y */
points.push_back (Duple (0, 0));
points.push_back (Duple (_heads[which].width, 0));
points.push_back (Duple (_heads[which].width / 2, _heads[which].height));
points.push_back (Duple (0, 0));
}
_heads[which].polygon->set (points);
}
/** Set the color of our line and arrow heads.
* @param color New color.
*/
void
Arrow::set_color (Gtkmm2ext::Color color)
{
_line->set_outline_color (color);
for (int i = 0; i < 2; ++i) {
if (_heads[i].polygon) {
_heads[i].polygon->set_outline_color (color);
_heads[i].polygon->set_fill_color (color);
}
}
}
bool
Arrow::covers (Duple const & point) const
{
if (_heads[0].polygon && _heads[0].polygon->covers (point)) {
return true;
}
if (_line && _line->covers (point)) {
return true;
}
if (_heads[1].polygon && _heads[1].polygon->covers (point)) {
return true;
}
return false;
}