ardour/livetrax
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first pass at tightening up waveform drawing algorithm to generally round down when dealing with fractional pixels

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This commit is contained in:
Paul Davis 2014-05-07 10:35:45 -04:00
parent 6142c814bf
commit e99c8960c0
1 changed files with 4 additions and 6 deletions
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10
libs/canvas/wave_view.cc
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@ -419,9 +419,7 @@ WaveView::ensure_cache (framepos_t start, framepos_t end) const
_sample_start = max ((framepos_t) 0, (center - canvas_samples));
_sample_end = min (center + canvas_samples, _region->source_length (0));
double pixel_start = floor (_sample_start / (double) _samples_per_pixel);
double pixel_end = ceil (_sample_end / (double) _samples_per_pixel);
int n_peaks = llrintf (pixel_end - pixel_start);
const int n_peaks = llrintf ((_sample_end - _sample_start)/ (double) _samples_per_pixel);
boost::scoped_array<ARDOUR::PeakData> peaks (new PeakData[n_peaks]);
@ -442,7 +440,7 @@ WaveView::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) cons
return;
}
Rect self = item_to_window (Rect (0.0, 0.0, floor (_region->length() / _samples_per_pixel), _height));
Rect self = item_to_window (Rect (0.0, 0.0, _region->length() / _samples_per_pixel, _height));
boost::optional<Rect> d = self.intersection (area);
if (!d) {
@ -452,12 +450,12 @@ WaveView::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) cons
Rect draw = d.get();
/* window coordinates - pixels where x=0 is the left edge of the canvas
* window. We round up and down in case we were asked to
* window. We round down in case we were asked to
* draw "between" pixels at the start and/or end.
*/
const double draw_start = floor (draw.x0);
const double draw_end = ceil (draw.x1);
const double draw_end = floor (draw.x1);
// cerr << "Need to draw " << draw_start << " .. " << draw_end << endl;