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tentative intermediate state for ArdourCanvas::Curve

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This commit is contained in:
Paul Davis 2014-03-04 10:04:49 -05:00
parent dde4d3bbc3
commit c29d392b0c
1 changed files with 64 additions and 68 deletions
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132
libs/canvas/curve.cc
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@ -252,7 +252,7 @@ Curve::smooth (Points::size_type p1, Points::size_type p2, Points::size_type p3,
}
}
/** Given a position within the x-axis range of the
/** Given a fractional position within the x-axis range of the
* curve, return the corresponding y-axis value
*/
@ -294,15 +294,21 @@ Curve::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
* with this.
*/
double x;
double y;
context->save ();
context->rectangle (area.x0, area.y0, area.width(),area.height());
context->clip ();
if (!_bounding_box) {
return;
}
Rect draw = area;
setup_outline_context (context);
/*
double r, g, b;
r = (random() % 255) / 255.0;
g = (random() % 255) / 255.0;
b = (random() % 255) / 255.0;
context->set_source_rgb (r, g, b);
*/
if (_points.size() == 2) {
/* straight line */
@ -317,77 +323,68 @@ Curve::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
} else {
/* curve of at least 3 points */
const double xfront = _points.front().x;
const double xextent = _points.back().x - xfront;
/* move through points to find the first one inside the
* rendering area
*/
Points::const_iterator edge = _points.end();
bool edge_found = false;
/* clamp actual draw to area bound by points, rather than our bounding box which is slightly different */
for (Points::const_iterator p = _points.begin(); p != _points.end(); ++p) {
Duple w (item_to_window (Duple ((*p).x, 0.0)));
if (w.x >= area.x0) {
edge_found = true;
break;
}
edge = p;
Duple w1 = item_to_window (Duple (_points.front().x, 0.0));
Duple w2 = item_to_window (Duple (_points.back().x, 0.0));
if (draw.x0 < w1.x) {
draw.x0 = w1.x;
}
if (edge == _points.end()) {
if (edge_found) {
edge = _points.begin();
if (draw.x1 >= w2.x) {
draw.x1 = w2.x;
}
std::cerr << "Draw " << draw << " win-x = " << w1 << " .. " << w2 << std::endl;
/* 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 ();
Duple window_space;
#if 1
std::cerr << "begin draw at " << draw.x0 << " (" << item_space.x << ") which is " << xfract_offset << " into " << w1.x << " .. " << w2.x
<< " I = " << _points.front().x << " .. " << _points.back().x
<< std::endl;
#endif
/* draw the first point */
std::cerr << this << " redraw " << pixels << " pixels from " << draw.x0 << " .. " << draw.x0 + pixels << std::endl;
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 */
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 {
return;
}
}
std::cerr << "Start drawing " << distance (_points.begin(), edge) << " into points\n";
x = (*edge).x;
y = map_value (0.0);
Duple window_space = item_to_window (Duple (x, y));
context->move_to (window_space.x, window_space.y);
/* if the extent of this curve (in pixels) is small, then we don't need
* many segments.
*/
uint32_t nsegs = area.width();
double last_x = 0;
double xoffset = (x-xfront)/xextent;
// std::cerr << " draw " << nsegs << " segments\n";
for (uint32_t n = 1; n < nsegs; ++n) {
/* compute item space x coordinate of the start of this segment */
x = xoffset + (n / (double) nsegs);
y = map_value (x);
x += xfront + (xextent * x);
// std::cerr << "hspan @ " << x << ' ' << x - last_x << std::endl;
last_x = x;
window_space = item_to_window (Duple (x, y));
context->line_to (window_space.x, window_space.y);
if (window_space.x > area.x1) {
/* we're done - the last point was outside the redraw area along the x-axis */
break;
context->line_to (window_space.x, window_space.y);
}
std::cerr << window_space << ' ';
}
std::cerr << std::endl;
}
context->stroke ();
#if 0
/* add points */
setup_fill_context (context);
@ -396,8 +393,7 @@ Curve::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
context->arc (window_space.x, window_space.y, 5.0, 0.0, 2 * M_PI);
context->stroke ();
}
context->restore ();
#endif
}
bool