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Implement DrawSpline in wxSVGFileDC

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Drawing Bézier curves is supported natively in SVG so these curves
should be used instead of generic wxDC implementation based on
polygonal approximation.
This commit is contained in:
Artur Wieczorek 2021-07-04 19:22:02 +02:00
parent 02c90d126c
commit cc5bfc0fb1
2 changed files with 54 additions and 0 deletions
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3
include/wx/dcsvg.h
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@ -198,6 +198,9 @@ private:
virtual void DoDrawLines(int n, const wxPoint points[],
wxCoord xoffset, wxCoord yoffset) wxOVERRIDE;
#if wxUSE_SPLINES
void DoDrawSpline(const wxPointList* points) wxOVERRIDE;
#endif // wxUSE_SPLINES
virtual void DoDrawPoint(wxCoord x, wxCoord y) wxOVERRIDE;

51
src/common/dcsvg.cpp
View File

@ -630,6 +630,57 @@ void wxSVGFileDCImpl::DoDrawLines(int n, const wxPoint points[], wxCoord xoffset
}
}
#if wxUSE_SPLINES
void wxSVGFileDCImpl::DoDrawSpline(const wxPointList* points)
{
wxCHECK_RET(points, "NULL pointer to spline points");
wxCHECK_RET(points->size() >= 2, "incomplete list of spline points");
NewGraphicsIfNeeded();
wxPointList::const_iterator itPt = points->begin();
const wxPoint* pt = *itPt; ++itPt;
wxPoint2DDouble p1(*pt);
pt = *itPt; ++itPt;
wxPoint2DDouble p2(*pt);
wxPoint2DDouble p3 = (p1 + p2) / 2.0;
wxString s = " <path d=\"";
s += wxString::Format("M %s %s L %s %s",
NumStr(p1.m_x), NumStr(p1.m_y), NumStr(p3.m_x), NumStr(p3.m_y));
CalcBoundingBox(wxRound(p1.m_x), wxRound(p1.m_y));
CalcBoundingBox(wxRound(p3.m_x), wxRound(p3.m_y));
while ( itPt != points->end() )
{
pt = *itPt; ++itPt;
wxPoint2DDouble p0 = p3;
p1 = p2;
p2 = *pt;
p3 = (p1 + p2) / 2.0;
// Calculate using degree elevation to a cubic bezier
wxPoint2DDouble c1 = (p0 + (p1 * 2.0)) / 3.0;
wxPoint2DDouble c2 = ((p1 * 2.0) + p3) / 3.0;
s += wxString::Format(" C %s %s, %s %s, %s %s",
NumStr(c1.m_x), NumStr(c1.m_y), NumStr(c2.m_x), NumStr(c2.m_y), NumStr(p3.m_x), NumStr(p3.m_y));
CalcBoundingBox(wxRound(p0.m_x), wxRound(p0.m_y));
CalcBoundingBox(wxRound(p3.m_x), wxRound(p3.m_y));
}
s += wxString::Format(" L %s %s", NumStr(p2.m_x), NumStr(p2.m_y));
CalcBoundingBox(wxRound(p2.m_x), wxRound(p2.m_y));
s += wxString::Format("\" style=\"fill:none\" %s %s/>\n",
GetRenderMode(m_renderingMode), GetPenPattern(m_pen));
write(s);
}
#endif // wxUSE_SPLINES
void wxSVGFileDCImpl::DoDrawPoint(wxCoord x, wxCoord y)
{
NewGraphicsIfNeeded();