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SvgArc fix

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git-svn-id: svn://ultimatepp.org/upp/trunk@872 f0d560ea-af0d-0410-9eb7-867de7ffcac7
This commit is contained in:
cxl 2009-02-16 16:36:11 +00:00
parent ccd96539bf
commit ffbb807daa
1 changed files with 53 additions and 53 deletions
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106
uppsrc/Painter/SvgArc.cpp
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@ -1,53 +1,53 @@
#include "Painter.h" #include "Painter.h"
NAMESPACE_UPP NAMESPACE_UPP
void Painter::DoSvgArc(const Pointf& rr, double xangle, int large, int sweep, void Painter::DoSvgArc(const Pointf& rr, double xangle, int large, int sweep,
const Pointf& p1, const Pointf& p0) const Pointf& p1, const Pointf& p0)
{ {
Pointf r(fabs(rr.x), fabs(rr.y)); Pointf r(fabs(rr.x), fabs(rr.y));
Xform2D m = Xform2D::Rotation(-xangle); Xform2D m = Xform2D::Rotation(-xangle);
Pointf d1 = m.Transform(Mid(p0, p1)); Pointf d1 = m.Transform(0.5 * (p0 - p1));
Pointf pr = r * r; Pointf pr = r * r;
Pointf p = d1 * d1; Pointf p = d1 * d1;
double check = p.x / pr.x + p.y / pr.y; double check = p.x / pr.x + p.y / pr.y;
if(check > 1) if(check > 1)
r *= sqrt(check); r *= sqrt(check);
m.x /= r.x; m.x /= r.x;
m.y /= r.y; m.y /= r.y;
Pointf q0 = m.Transform(p0); Pointf q0 = m.Transform(p0);
Pointf q1 = m.Transform(p1); Pointf q1 = m.Transform(p1);
double d = SquaredDistance(q0, q1); double d = SquaredDistance(q0, q1);
double sfactor_sq = 1.0 / d - 0.25; double sfactor_sq = 1.0 / d - 0.25;
if(sfactor_sq < 0) if(sfactor_sq < 0)
sfactor_sq = 0; sfactor_sq = 0;
double sfactor = sqrt(sfactor_sq); double sfactor = sqrt(sfactor_sq);
if(sweep == large) if(sweep == large)
sfactor = -sfactor; sfactor = -sfactor;
Pointf c(0.5 * (q0.x + q1.x) - sfactor * (q1.y - q0.y), Pointf c(0.5 * (q0.x + q1.x) - sfactor * (q1.y - q0.y),
0.5 * (q0.y + q1.y) + sfactor * (q1.x - q0.x)); 0.5 * (q0.y + q1.y) + sfactor * (q1.x - q0.x));
double theta = Bearing(q0 - c); double theta = Bearing(q0 - c);
double th_sweep = Bearing(q1 - c) - theta; double th_sweep = Bearing(q1 - c) - theta;
if(th_sweep < 0 && sweep) if(th_sweep < 0 && sweep)
th_sweep += 2 * M_PI; th_sweep += 2 * M_PI;
else else
if(th_sweep > 0 && !sweep) if(th_sweep > 0 && !sweep)
th_sweep -= 2 * M_PI; th_sweep -= 2 * M_PI;
int nsegs = int(ceil(fabs(th_sweep / (M_PI * 0.5 + 0.001)))); int nsegs = int(ceil(fabs(th_sweep / (M_PI * 0.5 + 0.001))));
m = Xform2D::Rotation(xangle); m = Xform2D::Rotation(xangle);
m.x *= r; m.x *= r;
m.y *= r; m.y *= r;
for(int i = 0; i < nsegs; i++) { for(int i = 0; i < nsegs; i++) {
double th0 = theta + i * th_sweep / nsegs; double th0 = theta + i * th_sweep / nsegs;
double th1 = theta + (i + 1) * th_sweep / nsegs; double th1 = theta + (i + 1) * th_sweep / nsegs;
double thHalf = 0.5 * (th1 - th0); double thHalf = 0.5 * (th1 - th0);
double t = (8.0 / 3.0) * sin(thHalf * 0.5) * sin(thHalf * 0.5) / sin(thHalf); double t = (8.0 / 3.0) * sin(thHalf * 0.5) * sin(thHalf * 0.5) / sin(thHalf);
double x3 = c.x + cos(th1); double x3 = c.x + cos(th1);
double y3 = c.y + sin(th1); double y3 = c.y + sin(th1);
Cubic(m.Transform(c.x + cos(th0) - t * sin(th0), c.y + sin(th0) + t * cos(th0)), Cubic(m.Transform(c.x + cos(th0) - t * sin(th0), c.y + sin(th0) + t * cos(th0)),
m.Transform(x3 + t * sin(th1), y3 - t * cos(th1)), m.Transform(x3 + t * sin(th1), y3 - t * cos(th1)),
m.Transform(x3, y3)); m.Transform(x3, y3));
} }
} }
END_UPP_NAMESPACE END_UPP_NAMESPACE