diff options
Diffstat (limited to 'libs/canvas')
| -rw-r--r-- | libs/canvas/curve.cc | 60 |
1 files changed, 29 insertions, 31 deletions
diff --git a/libs/canvas/curve.cc b/libs/canvas/curve.cc index 44637b8063..54d36bbc9b 100644 --- a/libs/canvas/curve.cc +++ b/libs/canvas/curve.cc @@ -283,10 +283,15 @@ Curve::map_value (double x) const void Curve::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const { - if (!_outline || _points.size() < 2) { + if (!_outline || _points.size() < 2 || !_bounding_box) { return; } + Rect self = item_to_window (_bounding_box.get()); + boost::optional<Rect> d = self.intersection (area); + assert (d); + Rect draw = d.get (); + /* Our approach is to always draw n_segments across our total size. * * This is very inefficient if we are asked to only draw a small @@ -294,21 +299,9 @@ Curve::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const * with this. */ - double y; - - 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 */ @@ -320,15 +313,31 @@ Curve::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const window_space = item_to_window (_points.back()); context->line_to (window_space.x, window_space.y); + context->stroke (); + } else { /* curve of at least 3 points */ - - /* clamp actual draw to area bound by points, rather than our bounding box which is slightly different */ + + /* x-axis limits of the curve, in window space coordinates */ Duple w1 = item_to_window (Duple (_points.front().x, 0.0)); Duple w2 = item_to_window (Duple (_points.back().x, 0.0)); + /* clamp actual draw to area bound by points, rather than our bounding box which is slightly different */ + + context->save (); + context->rectangle (draw.x0, draw.y0, draw.width(), draw.height()); + context->clip (); + + /* expand drawing area by several pixels on each side to avoid cairo stroking effects at the boundary. + they will still occur, but cairo's clipping will hide them. + */ + + draw = draw.expand (4.0); + + /* now clip it to the actual points in the curve */ + if (draw.x0 < w1.x) { draw.x0 = w1.x; } @@ -337,8 +346,6 @@ Curve::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const 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 */ @@ -348,22 +355,14 @@ Curve::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const 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); + double y = map_value (xfract); /* convert to window space for drawing */ window_space = item_to_window (Duple (0.0, y)); /* x-value is irrelevant */ @@ -377,12 +376,11 @@ Curve::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const } else { context->line_to (window_space.x, window_space.y); } - std::cerr << window_space << ' '; } - std::cerr << std::endl; - } - context->stroke (); + context->stroke (); + context->restore (); + } #if 0 /* add points */ |