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// SPDX-License-Identifier: GPL-2.0-or-later
/**
* A class to represent a single Bezier control curve, either a line or a cubic Bezier.
*/
/*
* Author:
* Tavmjong Bah
*
* Copyright (C) 2020 Tavmjong Bah
*
* Rewrite of SPCtrlLine and SPCtrlCurve
*
* Released under GNU GPL v2+, read the file 'COPYING' for more information.
*/
#include <2geom/bezier-curve.h>
#include "canvas-item-curve.h"
#include "color.h" // SP_RGBA_x_F
#include "ui/widget/canvas.h"
namespace Inkscape {
/**
* Create an null control curve.
*/
CanvasItemCurve::CanvasItemCurve(CanvasItemGroup *group)
: CanvasItem(group)
{
_name = "CanvasItemCurve:Null";
_pickable = false; // For now, nobody gets events from this class!
}
/**
* Create a linear control curve. Points are in document coordinates.
*/
CanvasItemCurve::CanvasItemCurve(CanvasItemGroup *group, Geom::Point const &p0, Geom::Point const &p1)
: CanvasItem(group)
, _curve(std::make_unique<Geom::LineSegment>(p0, p1))
{
_name = "CanvasItemCurve:Line";
_pickable = false; // For now, nobody gets events from this class!
request_update();
}
/**
* Create a cubic Bezier control curve. Points are in document coordinates.
*/
CanvasItemCurve::CanvasItemCurve(CanvasItemGroup *group,
Geom::Point const &p0, Geom::Point const &p1,
Geom::Point const &p2, Geom::Point const &p3)
: CanvasItem(group)
, _curve(std::make_unique<Geom::CubicBezier>(p0, p1, p2, p3))
{
_name = "CanvasItemCurve:CubicBezier";
_pickable = false; // For now, nobody gets events from this class!
request_update();
}
/**
* Set a linear control curve. Points are in document coordinates.
*/
void CanvasItemCurve::set_coords(Geom::Point const &p0, Geom::Point const &p1)
{
_name = "CanvasItemCurve:Line";
_curve = std::make_unique<Geom::LineSegment>(p0, p1);
request_update();
}
/**
* Set a cubic Bezier control curve. Points are in document coordinates.
*/
void CanvasItemCurve::set_coords(Geom::Point const &p0, Geom::Point const &p1, Geom::Point const &p2, Geom::Point const &p3)
{
_name = "CanvasItemCurve:CubicBezier";
_curve = std::make_unique<Geom::CubicBezier>(p0, p1, p2, p3);
request_update();
}
/**
* Set stroke width.
*/
void CanvasItemCurve::set_width(int w)
{
width = w;
request_update();
}
/**
* Set background stroke alpha.
*/
void CanvasItemCurve::set_bg_alpha(float alpha)
{
bg_alpha = alpha;
request_update();
}
/**
* Returns distance between point in canvas units and nearest point on curve.
*/
double CanvasItemCurve::closest_distance_to(Geom::Point const &p)
{
double d = Geom::infinity();
if (_curve) {
Geom::BezierCurve curve = *_curve;
curve *= _affine; // Document to canvas.
Geom::Point n = curve.pointAt(curve.nearestTime(p));
d = Geom::distance(p, n);
}
return d;
}
/**
* Returns true if point p (in canvas units) is within tolerance (canvas units) distance of curve.
*/
bool CanvasItemCurve::contains(Geom::Point const &p, double tolerance)
{
return closest_distance_to(p) <= tolerance;
}
/**
* Update and redraw control curve.
*/
void CanvasItemCurve::update(Geom::Affine const &affine)
{
if (_affine == affine && !_need_update) {
// Nothing to do.
return;
}
if (!_curve) {
return; // No curve! See node.h.
}
// Queue redraw of old area (erase previous content).
request_redraw(); // This is actually never useful as curves are always deleted
// and recreated when a node is moved! But keep it in case we
// change that. CHECK
// Get new bounds
_affine = affine;
// Trade off between updating a larger area (typically twice for Beziers?) vs computation time for bounds.
_bounds = _curve->boundsExact(); // Document units.
_bounds *= _affine; // Document to canvas.
_bounds.expandBy(2); // Room for stroke.
// Queue redraw of new area
request_redraw();
_need_update = false;
}
/**
* Render curve to screen via Cairo.
*/
void CanvasItemCurve::render(Inkscape::CanvasItemBuffer *buf)
{
if (!buf) {
std::cerr << "CanvasItemCurve::Render: No buffer!" << std::endl;
return;
}
if (!_curve) {
// Curve not defined (see node.h).
return;
}
if (!_visible) {
// Hidden
return;
}
if (_curve->isDegenerate()) {
// Nothing to render!
return;
}
Geom::BezierCurve curve = *_curve;
curve *= _affine; // Document to canvas.
curve *= Geom::Translate(-buf->rect.min()); // Canvas to screen.
buf->cr->save();
buf->cr->begin_new_path();
if (curve.size() == 2) {
// Line
buf->cr->move_to(curve[0].x(), curve[0].y());
buf->cr->line_to(curve[1].x(), curve[1].y());
} else {
// Curve
buf->cr->move_to(curve[0].x(), curve[0].y());
buf->cr->curve_to(curve[1].x(), curve[1].y(), curve[2].x(), curve[2].y(), curve[3].x(), curve[3].y());
}
buf->cr->set_source_rgba(1.0, 1.0, 1.0, bg_alpha);
buf->cr->set_line_width(background_width);
buf->cr->stroke_preserve();
buf->cr->set_source_rgba(SP_RGBA32_R_F(_stroke), SP_RGBA32_G_F(_stroke),
SP_RGBA32_B_F(_stroke), SP_RGBA32_A_F(_stroke));
buf->cr->set_line_width(width);
buf->cr->stroke();
// Uncomment to show bounds
// Geom::Rect bounds = _bounds;
// bounds.expandBy(-1);
// bounds -= buf->rect.min();
// buf->cr->set_source_rgba(1.0, 0.0, 0.0, 1.0);
// buf->cr->rectangle(bounds.min().x(), bounds.min().y(), bounds.width(), bounds.height());
// buf->cr->stroke();
buf->cr->restore();
}
} // namespace Inkscape
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :
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