1 files changed, 236 insertions, 0 deletions
diff --git a/src/display/control/canvas-item-curve.cpp b/src/display/control/canvas-item-curve.cpp
new file mode 100644
index 0000000..a99a154
--- /dev/null
+++ b/src/display/control/canvas-item-curve.cpp
@@ -0,0 +1,236 @@
+// 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 :