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Fixes #139: Cut lines when they are outside of the chart grid.

This commit is contained in:
Kolan Sh 2017-09-06 10:40:09 +03:00
parent 82aa857a35
commit 002e995b14
1 changed files with 85 additions and 6 deletions
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91
src/Chart.vala
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@ -908,6 +908,39 @@ namespace Gtk.CairoChart {
/ (s.axis_y.max - s.axis_y.min) * (s.place.y_high - s.place.y_low));
}
protected virtual bool point_in_rect (Point p, double x0, double x1, double y0, double y1) {
if ( (x0 <= p.x <= x1 || x1 <= p.x <= x0)
&& (y0 <= p.y <= y1 || y1 <= p.y <= y0))
return true;
return false;
}
protected virtual bool point_in_plot_area (Point p) {
if (point_in_rect (p, plot_area_x_min, plot_area_x_max, plot_area_y_min, plot_area_y_max))
return true;
return false;
}
protected virtual bool hcross (Point a1, Point a2, Float128 h_x1, Float128 h_x2, Float128 h_y, out Float128 x) {
x = 0;
if (a1.y == a2.y) return false;
if (a1.y >= h_y && a2.y >= h_y || a1.y <= h_y && a2.y <= h_y) return false;
x = a1.x + (a2.x - a1.x) * (h_y - a1.y) / (a2.y - a1.y);
if (h_x1 <= x <= h_x2 || h_x2 <= x <= h_x1)
return true;
return false;
}
protected virtual bool vcross (Point a1, Point a2, Float128 v_x, Float128 v_y1, Float128 v_y2, out Float128 y) {
y = 0;
if (a1.x == a2.x) return false;
if (a1.x >= v_x && a2.x >= v_x || a1.x <= v_x && a2.x <= v_x) return false;
y = a1.y + (a2.y - a1.y) * (v_x - a1.x) / (a2.x - a1.x);
if (v_y1 <= y <= v_y2 || v_y2 <= y <= v_y1)
return true;
return false;
}
delegate int PointComparator(Point a, Point b);
void sort_points(Point[] points, PointComparator compare) {
for(var i = 0; i < points.length; ++i) {
@ -921,6 +954,43 @@ namespace Gtk.CairoChart {
}
}
protected virtual bool cut_line (Point a, Point b, out Point c, out Point d) {
int ncross = 0;
Float128 x = 0, y = 0;
Point pc[4];
if (hcross(a, b, plot_area_x_min, plot_area_x_max, plot_area_y_min, out x))
pc[ncross++] = Point(x, plot_area_y_min);
if (hcross(a, b, plot_area_x_min, plot_area_x_max, plot_area_y_max, out x))
pc[ncross++] = Point(x, plot_area_y_max);
if (vcross(a, b, plot_area_x_min, plot_area_y_min, plot_area_y_max, out y))
pc[ncross++] = Point(plot_area_x_min, y);
if (vcross(a, b, plot_area_x_max, plot_area_y_min, plot_area_y_max, out y))
pc[ncross++] = Point(plot_area_x_max, y);
c = a;
d = b;
if (ncross == 0) {
if (point_in_plot_area (a) && point_in_plot_area (b))
return true;
return false;
}
if (ncross >= 2) {
c = pc[0]; d = pc[1];
return true;
}
if (ncross == 1) {
if (point_in_plot_area (a)) {
c = a;
d = pc[0];
return true;
} else if (point_in_plot_area (b)) {
c = b;
d = pc[0];
return true;
}
}
return false;
}
protected virtual void draw_series () {
for (int si = 0; si < series.length; ++si) {
var s = series[si];
@ -943,14 +1013,23 @@ namespace Gtk.CairoChart {
break;
}
set_line_style(s.line_style);
// move to s.points[0]
context.move_to (get_scr_x(s, points[0].x), get_scr_y(s, points[0].y));
// draw series line
for (int i = 1; i < points.length; ++i)
context.line_to (get_scr_x(s, points[i].x), get_scr_y(s, points[i].y));
for (int i = 1; i < points.length; ++i) {
Point c, d;
if (cut_line (Point(get_scr_x(s, points[i - 1].x), get_scr_y(s, points[i - 1].y)),
Point(get_scr_x(s, points[i].x), get_scr_y(s, points[i].y)),
out c, out d)) {
context.move_to (c.x, c.y);
context.line_to (d.x, d.y);
}
}
context.stroke();
for (int i = 0; i < points.length; ++i)
draw_marker_at_pos(s.marker_type, get_scr_x(s, points[i].x), get_scr_y(s, points[i].y));
for (int i = 0; i < points.length; ++i) {
var x = get_scr_x(s, points[i].x);
var y = get_scr_y(s, points[i].y);
if (point_in_plot_area (Point (x, y)))
draw_marker_at_pos(s.marker_type, x, y);
}
}
}