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Arc improvements

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git-svn-id: svn://ultimatepp.org/upp/trunk@865 f0d560ea-af0d-0410-9eb7-867de7ffcac7
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cxl 2009-02-14 23:00:15 +00:00
parent 726b5c058f
commit 708c0cf829
1 changed files with 25 additions and 132 deletions
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157
uppsrc/Painter/SvgArc.cpp
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@ -2,159 +2,52 @@
NAMESPACE_UPP
void Painter::DoArc(const Pointf& c, const Pointf& r, double angle, double sweep, double xangle)
{
int n_segs = int(ceil(fabs(sweep / (M_PI * 0.5 + 0.001))));
for (int i = 0; i < n_segs; i++) {
double th0 = angle + i * sweep / n_segs;
double th1 = angle + (i + 1) * sweep / n_segs;
double thHalf = 0.5 * (th1 - th0);
double t = (8.0 / 3.0) * sin(thHalf * 0.5) * sin(thHalf * 0.5) / sin(thHalf);
double x3 = c.x + cos(th1);
double y3 = c.y + sin(th1);
Xform2D m = Xform2D::Rotation(xangle);
m.x *= r;
m.y *= r;
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, y3));
}
}
// the arc handling code underneath is from XSVG (BSD license)
/*
* Copyright 2002 USC/Information Sciences Institute
*
* Permission to use, copy, modify, distribute, and sell this software
* and its documentation for any purpose is hereby granted without
* fee, provided that the above copyright notice appear in all copies
* and that both that copyright notice and this permission notice
* appear in supporting documentation, and that the name of
* Information Sciences Institute not be used in advertising or
* publicity pertaining to distribution of the software without
* specific, written prior permission. Information Sciences Institute
* makes no representations about the suitability of this software for
* any purpose. It is provided "as is" without express or implied
* warranty.
*
* INFORMATION SCIENCES INSTITUTE DISCLAIMS ALL WARRANTIES WITH REGARD
* TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL INFORMATION SCIENCES
* INSTITUTE BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA
* OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*
*/
void Painter::DoSvgArc(const Pointf& rr, double xangle, int large, int sweep,
const Pointf& p1, const Pointf& p0)
{
Pointf r(fabs(rr.x), fabs(rr.y));
Xform2D m = Xform2D::Rotation(-xangle);
Pointf d1 = m.Transform((p0 - p1) / 2);
Pointf Pr = r * r;
Pointf P = d1 * d1;
double check = P.x / Pr.x + P.y / Pr.y;
Pointf pr = r * r;
Pointf p = d1 * d1;
double check = p.x / pr.x + p.y / pr.y;
if(check > 1)
r *= sqrt(check);
m.x /= r.x;
m.y /= r.y;
Pointf q0 = m.Transform(p0);
Pointf q1 = m.Transform(p1);
double d = SquaredDistance(q1, q0);
double d = SquaredDistance(q0, q1);
double sfactor_sq = 1.0 / d - 0.25;
if(sfactor_sq < 0) sfactor_sq = 0;
if(sfactor_sq < 0)
sfactor_sq = 0;
double sfactor = sqrt(sfactor_sq);
if (sweep == large) sfactor = -sfactor;
if(sweep == large)
sfactor = -sfactor;
Pointf c(0.5 * (q0.x + q1.x) - sfactor * (q1.y - q0.y),
0.5 * (q0.y + q1.y) + sfactor * (q1.x - q0.x));
double th0 = Bearing(q0 - c);
double th_sweep = Bearing(q1 - c) - th0;
double theta = Bearing(q0 - c);
double th_sweep = Bearing(q1 - c) - theta;
if(th_sweep < 0 && sweep)
th_sweep += 2 * M_PI;
else
if(th_sweep > 0 && !sweep)
th_sweep -= 2 * M_PI;
DoArc(c, r, th0, th_sweep, xangle);
int nsegs = int(ceil(fabs(th_sweep / (M_PI * 0.5 + 0.001))));
m = Xform2D::Rotation(xangle);
m.x *= r;
m.y *= r;
for(int i = 0; i < nsegs; i++) {
double th0 = theta + i * th_sweep / nsegs;
double th1 = theta + (i + 1) * th_sweep / nsegs;
double thHalf = 0.5 * (th1 - th0);
double t = (8.0 / 3.0) * sin(thHalf * 0.5) * sin(thHalf * 0.5) / sin(thHalf);
double x3 = c.x + cos(th1);
double y3 = c.y + sin(th1);
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, y3));
}
}
#if 0
void Painter::DoSvgArc(double rx, double ry,
double x_axis_rotation, int large_arc_flag, int sweep_flag,
double x, double y, double curx, double cury)
{
double sin_th, cos_th;
double a00, a01, a10, a11;
double x0, y0, x1, y1, xc, yc;
double d, sfactor, sfactor_sq;
double th0, th1, th_arc;
int i, n_segs;
double dx, dy, dx1, dy1, Pr1, Pr2, Px, Py, check;
rx = fabs(rx);
ry = fabs(ry);
sin_th = sin(x_axis_rotation);
cos_th = cos(x_axis_rotation);
dx = (curx - x) / 2.0;
dy = (cury - y) / 2.0;
dx1 = cos_th * dx + sin_th * dy;
dy1 = -sin_th * dx + cos_th * dy;
Pr1 = rx * rx;
Pr2 = ry * ry;
Px = dx1 * dx1;
Py = dy1 * dy1;
/* Spec : check if radii are large enough */
check = Px / Pr1 + Py / Pr2;
if(check > 1) {
rx = rx * sqrt(check);
ry = ry * sqrt(check);
}
a00 = cos_th / rx;
a01 = sin_th / rx;
a10 = -sin_th / ry;
a11 = cos_th / ry;
x0 = a00 * curx + a01 * cury;
y0 = a10 * curx + a11 * cury;
x1 = a00 * x + a01 * y;
y1 = a10 * x + a11 * y;
/* (x0, y0) is current point in transformed coordinate space.
(x1, y1) is new point in transformed coordinate space.
The arc fits a unit-radius circle in this space.
*/
d = (x1 - x0) * (x1 - x0) + (y1 - y0) * (y1 - y0);
sfactor_sq = 1.0 / d - 0.25;
if (sfactor_sq < 0) sfactor_sq = 0;
sfactor = sqrt(sfactor_sq);
if (sweep_flag == large_arc_flag) sfactor = -sfactor;
xc = 0.5 * (x0 + x1) - sfactor * (y1 - y0);
yc = 0.5 * (y0 + y1) + sfactor * (x1 - x0);
/* (xc, yc) is center of the circle. */
th0 = atan2(y0 - yc, x0 - xc);
th1 = atan2(y1 - yc, x1 - xc);
th_arc = th1 - th0;
if (th_arc < 0 && sweep_flag)
th_arc += 2 * M_PI;
else if (th_arc > 0 && !sweep_flag)
th_arc -= 2 * M_PI;
n_segs = int(ceil(fabs(th_arc / (M_PI * 0.5 + 0.001))));
for (i = 0; i < n_segs; i++)
ArcSegment(xc, yc,
th0 + i * th_arc / n_segs,
th0 + (i + 1) * th_arc / n_segs,
rx, ry, x_axis_rotation);
}
#endif
END_UPP_NAMESPACE