*/
+#include <cmath>
#include <exception>
#include <algorithm>
using std::min;
using std::max;
-Curve::Curve (Group* parent)
- : Item (parent)
- , PolyItem (parent)
- , Fill (parent)
+Curve::Curve (Canvas* c)
+ : PolyItem (c)
, n_samples (0)
- , n_segments (512)
+ , points_per_segment (16)
+ , curve_fill (None)
{
- set_n_samples (256);
}
-/** Set the number of points to compute when we smooth the data points into a
- * curve.
- */
-void
-Curve::set_n_samples (Points::size_type n)
+Curve::Curve (Item* parent)
+ : PolyItem (parent)
+ , n_samples (0)
+ , points_per_segment (16)
+ , curve_fill (None)
{
- /* this only changes our appearance rather than the bounding box, so we
- just need to schedule a redraw rather than notify the parent of any
- changes
- */
- n_samples = n;
- samples.assign (n_samples, Duple (0.0, 0.0));
- interpolate ();
}
/** When rendering the curve, we will always draw a fixed number of straight
* render.
*/
void
-Curve::set_n_segments (uint32_t n)
+Curve::set_points_per_segment (uint32_t n)
{
/* this only changes our appearance rather than the bounding box, so we
just need to schedule a redraw rather than notify the parent of any
changes
*/
- n_segments = n;
+ points_per_segment = n;
+ interpolate ();
redraw ();
}
void
Curve::interpolate ()
{
- Points::size_type npoints = _points.size ();
-
- if (npoints < 3) {
- return;
- }
-
- Duple p;
- double boundary;
-
- const double xfront = _points.front().x;
- const double xextent = _points.back().x - xfront;
-
- /* initialize boundary curve points */
-
- p = _points.front();
- boundary = round (((p.x - xfront)/xextent) * (n_samples - 1));
-
- for (Points::size_type i = 0; i < boundary; ++i) {
- samples[i] = Duple (i, p.y);
- }
-
- p = _points.back();
- boundary = round (((p.x - xfront)/xextent) * (n_samples - 1));
-
- for (Points::size_type i = boundary; i < n_samples; ++i) {
- samples[i] = Duple (i, p.y);
- }
-
- for (int i = 0; i < (int) npoints - 1; ++i) {
-
- Points::size_type p1, p2, p3, p4;
-
- p1 = max (i - 1, 0);
- p2 = i;
- p3 = i + 1;
- p4 = min (i + 2, (int) npoints - 1);
-
- smooth (p1, p2, p3, p4, xfront, xextent);
- }
-
- /* make sure that actual data points are used with their exact values */
-
- for (Points::const_iterator p = _points.begin(); p != _points.end(); ++p) {
- uint32_t idx = (((*p).x - xfront)/xextent) * (n_samples - 1);
- samples[idx].y = (*p).y;
- }
-}
-
-/*
- * This function calculates the curve values between the control points
- * p2 and p3, taking the potentially existing neighbors p1 and p4 into
- * account.
- *
- * This function uses a cubic bezier curve for the individual segments and
- * calculates the necessary intermediate control points depending on the
- * neighbor curve control points.
- *
- */
-
-void
-Curve::smooth (Points::size_type p1, Points::size_type p2, Points::size_type p3, Points::size_type p4,
- double xfront, double xextent)
-{
- int i;
- double x0, x3;
- double y0, y1, y2, y3;
- double dx, dy;
- double slope;
-
- /* the outer control points for the bezier curve. */
-
- x0 = _points[p2].x;
- y0 = _points[p2].y;
- x3 = _points[p3].x;
- y3 = _points[p3].y;
-
- /*
- * the x values of the inner control points are fixed at
- * x1 = 2/3*x0 + 1/3*x3 and x2 = 1/3*x0 + 2/3*x3
- * this ensures that the x values increase linearily with the
- * parameter t and enables us to skip the calculation of the x
- * values altogehter - just calculate y(t) evenly spaced.
- */
-
- dx = x3 - x0;
- dy = y3 - y0;
-
- if (dx <= 0) {
- /* error? */
- return;
- }
-
- if (p1 == p2 && p3 == p4) {
- /* No information about the neighbors,
- * calculate y1 and y2 to get a straight line
- */
- y1 = y0 + dy / 3.0;
- y2 = y0 + dy * 2.0 / 3.0;
-
- } else if (p1 == p2 && p3 != p4) {
-
- /* only the right neighbor is available. Make the tangent at the
- * right endpoint parallel to the line between the left endpoint
- * and the right neighbor. Then point the tangent at the left towards
- * the control handle of the right tangent, to ensure that the curve
- * does not have an inflection point.
- */
- slope = (_points[p4].y - y0) / (_points[p4].x - x0);
-
- y2 = y3 - slope * dx / 3.0;
- y1 = y0 + (y2 - y0) / 2.0;
-
- } else if (p1 != p2 && p3 == p4) {
-
- /* see previous case */
- slope = (y3 - _points[p1].y) / (x3 - _points[p1].x);
-
- y1 = y0 + slope * dx / 3.0;
- y2 = y3 + (y1 - y3) / 2.0;
-
-
- } else /* (p1 != p2 && p3 != p4) */ {
-
- /* Both neighbors are available. Make the tangents at the endpoints
- * parallel to the line between the opposite endpoint and the adjacent
- * neighbor.
- */
-
- slope = (y3 - _points[p1].y) / (x3 - _points[p1].x);
-
- y1 = y0 + slope * dx / 3.0;
-
- slope = (_points[p4].y - y0) / (_points[p4].x - x0);
-
- y2 = y3 - slope * dx / 3.0;
- }
-
- /*
- * finally calculate the y(t) values for the given bezier values. We can
- * use homogenously distributed values for t, since x(t) increases linearily.
- */
-
- dx = dx / xextent;
-
- int limit = round (dx * (n_samples - 1));
- const int idx_offset = round (((x0 - xfront)/xextent) * (n_samples - 1));
-
- for (i = 0; i <= limit; i++) {
- double y, t;
- Points::size_type index;
-
- t = i / dx / (n_samples - 1);
-
- y = y0 * (1-t) * (1-t) * (1-t) +
- 3 * y1 * (1-t) * (1-t) * t +
- 3 * y2 * (1-t) * t * t +
- y3 * t * t * t;
-
- index = i + idx_offset;
-
- if (index < n_samples) {
- Duple d (i, max (y, 0.0));
- samples[index] = d;
- }
- }
-}
-
-/** Given a fractional position within the x-axis range of the
- * curve, return the corresponding y-axis value
- */
-
-double
-Curve::map_value (double x) const
-{
- if (x > 0.0 && x < 1.0) {
-
- double f;
- Points::size_type index;
-
- /* linearly interpolate between two of our smoothed "samples"
- */
-
- x = x * (n_samples - 1);
- index = (Points::size_type) x; // XXX: should we explicitly use floor()?
- f = x - index;
-
- return (1.0 - f) * samples[index].y + f * samples[index+1].y;
-
- } else if (x >= 1.0) {
- return samples.back().y;
- } else {
- return samples.front().y;
- }
+ samples.clear ();
+ InterpolatedCurve::interpolate (_points, points_per_segment, CatmullRomCentripetal, false, samples);
+ n_samples = samples.size();
}
void
* section of the curve. For now we rely on cairo clipping to help
* with this.
*/
-
+
setup_outline_context (context);
window_space = item_to_window (_points.back());
context->line_to (window_space.x, window_space.y);
- context->stroke ();
+
+ switch (curve_fill) {
+ case None:
+ context->stroke();
+ break;
+ case Inside:
+ context->stroke_preserve ();
+ window_space = item_to_window (Duple(_points.back().x, draw.height()));
+ context->line_to (window_space.x, window_space.y);
+ window_space = item_to_window (Duple(_points.front().x, draw.height()));
+ context->line_to (window_space.x, window_space.y);
+ context->close_path();
+ setup_fill_context(context);
+ context->fill ();
+ break;
+ case Outside:
+ context->stroke_preserve ();
+ window_space = item_to_window (Duple(_points.back().x, 0.0));
+ context->line_to (window_space.x, window_space.y);
+ window_space = item_to_window (Duple(_points.front().x, 0.0));
+ context->line_to (window_space.x, window_space.y);
+ context->close_path();
+ setup_fill_context(context);
+ context->fill ();
+ break;
+ }
} else {
draw = draw.expand (4.0);
/* now clip it to the actual points in the curve */
-
+
if (draw.x0 < w1.x) {
draw.x0 = w1.x;
}
draw.x1 = w2.x;
}
- /* full width of the curve */
- const double xextent = _points.back().x - _points.front().x;
- /* Determine where the first drawn point will be */
- Duple item_space = window_to_item (Duple (draw.x0, 0)); /* y value is irrelevant */
- /* determine the fractional offset of this location into the overall extent of the curve */
- const double xfract_offset = (item_space.x - _points.front().x)/xextent;
- const uint32_t pixels = draw.width ();
+ /* find left and right-most sample */
Duple window_space;
+ Points::size_type left = 0;
+ Points::size_type right = n_samples;
- /* draw the first point */
-
- for (uint32_t pixel = 0; pixel < pixels; ++pixel) {
-
- /* fractional distance into the total horizontal extent of the curve */
- double xfract = xfract_offset + (pixel / xextent);
- /* compute vertical coordinate (item-space) at that location */
- double y = map_value (xfract);
-
- /* convert to window space for drawing */
- window_space = item_to_window (Duple (0.0, y)); /* x-value is irrelevant */
-
- /* we are moving across the draw area pixel-by-pixel */
- window_space.x = draw.x0 + pixel;
-
- /* plot this point */
- if (pixel == 0) {
- context->move_to (window_space.x, window_space.y);
- } else {
- context->line_to (window_space.x, window_space.y);
- }
+ for (Points::size_type idx = 0; idx < n_samples - 1; ++idx) {
+ left = idx;
+ window_space = item_to_window (Duple (samples[idx].x, 0.0));
+ if (window_space.x >= draw.x0) break;
+ }
+ for (Points::size_type idx = n_samples; idx > left + 1; --idx) {
+ window_space = item_to_window (Duple (samples[idx].x, 0.0));
+ if (window_space.x <= draw.x1) break;
+ right = idx;
}
- context->stroke ();
+ /* draw line between samples */
+ window_space = item_to_window (Duple (samples[left].x, samples[left].y));
+ context->move_to (window_space.x, window_space.y);
+ for (uint32_t idx = left + 1; idx < right; ++idx) {
+ window_space = item_to_window (Duple (samples[idx].x, samples[idx].y));
+ context->line_to (window_space.x, window_space.y);
+ }
+
+ switch (curve_fill) {
+ case None:
+ context->stroke();
+ break;
+ case Inside:
+ context->stroke_preserve ();
+ window_space = item_to_window (Duple (samples[right-1].x, draw.height()));
+ context->line_to (window_space.x, window_space.y);
+ window_space = item_to_window (Duple (samples[left].x, draw.height()));
+ context->line_to (window_space.x, window_space.y);
+ context->close_path();
+ setup_fill_context(context);
+ context->fill ();
+ break;
+ case Outside:
+ context->stroke_preserve ();
+ window_space = item_to_window (Duple (samples[right-1].x, 0.0));
+ context->line_to (window_space.x, window_space.y);
+ window_space = item_to_window (Duple (samples[left].x, 0.0));
+ context->line_to (window_space.x, window_space.y);
+ context->close_path();
+ setup_fill_context(context);
+ context->fill ();
+ break;
+ }
context->restore ();
}
#if 0
/* add points */
-
- setup_fill_context (context);
+ setup_outline_context (context);
for (Points::const_iterator p = _points.begin(); p != _points.end(); ++p) {
Duple window_space (item_to_window (*p));
context->arc (window_space.x, window_space.y, 5.0, 0.0, 2 * M_PI);
bool
Curve::covers (Duple const & pc) const
{
- Duple point = canvas_to_item (pc);
+ Duple point = window_to_item (pc);
/* O(N) N = number of points, and not accurate */
projects / ardour.git / blobdiff