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Groups > comp.lang.java.programmer > #3703
| From | Jeff Higgins <jeff@invalid.invalid> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: boolean to int : was char to decimal |
| Date | 2011-05-06 13:26 -0400 |
| Organization | A noiseless patient Spider |
| Message-ID | <iq1asr$tps$1@dont-email.me> (permalink) |
| References | <92ea64F3avU1@mid.individual.net> <Xns9EDBB8224D5B6vaj4088ianshef@138.125.254.103> <iptlkq$62g$2@lust.ihug.co.nz> <iq0r9c$efs$1@dont-email.me> |
On 05/06/2011 09:00 AM, Jeff Higgins wrote:
> On 05/05/2011 04:03 AM, Lawrence D'Oliveiro wrote:
>> In message<Xns9EDBB8224D5B6vaj4088ianshef@138.125.254.103>, Ian Shef
>> wrote:
>>
>> Funny, they could do all this for char, but not for boolean.
>
> Recently I was translating a piece of C++ code to Java.
> I'm wondering how others might make this translation.
> Thanks, JSH.
>
> double d2;
> double d3;
> double e;
>
> C++ test:
> int test = (int(d2 > e) << 1) + int(d3 > e);
>
> Java test:
> int t = d2 > e ? 1<<1 : 0;
> int test = d3 > e ? t+1 : t;
>
> switch(test)
> { case(0):
> case(1):
> case(2):
> case(3):
> }
>
>
Thanks for the responses.
Yes, the nested if/else seems more clear in the above short example.
Now I wonder about the original author's motivation for
the use of switch statement. Code clarity, optimization, idiomatics?
Somehow the code seems easier for me to read with the use of the
switch simply because of the length of the intervening code.
void curve4_div::recursive_bezier(double x1, double y1, double x2,
double y2, double x3, double y3, double x4, double y4, unsigned level) {
if (level > curve_recursion_limit) {
return;
}
// Calculate all the mid-points of the line segments
//----------------------
double x12 = (x1 + x2) / 2;
double y12 = (y1 + y2) / 2;
double x23 = (x2 + x3) / 2;
double y23 = (y2 + y3) / 2;
double x34 = (x3 + x4) / 2;
double y34 = (y3 + y4) / 2;
double x123 = (x12 + x23) / 2;
double y123 = (y12 + y23) / 2;
double x234 = (x23 + x34) / 2;
double y234 = (y23 + y34) / 2;
double x1234 = (x123 + x234) / 2;
double y1234 = (y123 + y234) / 2;
// Try to approximate the full cubic curve by a single straight line
//------------------
double dx = x4 - x1;
double dy = y4 - y1;
double d2 = fabs(((x2 - x4) * dy - (y2 - y4) * dx));
double d3 = fabs(((x3 - x4) * dy - (y3 - y4) * dx));
double da1, da2, k;
switch ((int(d2 > curve_collinearity_epsilon) << 1) +
int(d3 > curve_collinearity_epsilon)) {
case 0:
// All collinear OR p1==p4
//----------------------
k = dx * dx + dy * dy;
if (k == 0) {
d2 = calc_sq_distance(x1, y1, x2, y2);
d3 = calc_sq_distance(x4, y4, x3, y3);
} else {
k = 1 / k;
da1 = x2 - x1;
da2 = y2 - y1;
d2 = k * (da1 * dx + da2 * dy);
da1 = x3 - x1;
da2 = y3 - y1;
d3 = k * (da1 * dx + da2 * dy);
if (d2 > 0 && d2 < 1 && d3 > 0 && d3 < 1) {
// Simple collinear case, 1---2---3---4
// We can leave just two endpoints
return;
}
if (d2 <= 0)
d2 = calc_sq_distance(x2, y2, x1, y1);
else if (d2 >= 1)
d2 = calc_sq_distance(x2, y2, x4, y4);
else
d2 = calc_sq_distance(x2, y2, x1 + d2 * dx, y1 + d2 * dy);
if (d3 <= 0)
d3 = calc_sq_distance(x3, y3, x1, y1);
else if (d3 >= 1)
d3 = calc_sq_distance(x3, y3, x4, y4);
else
d3 = calc_sq_distance(x3, y3, x1 + d3 * dx, y1 + d3 * dy);
}
if (d2 > d3) {
if (d2 < m_distance_tolerance_square) {
m_points.add(point_d(x2, y2));
return;
}
} else {
if (d3 < m_distance_tolerance_square) {
m_points.add(point_d(x3, y3));
return;
}
}
break;
case 1:
// p1,p2,p4 are collinear, p3 is significant
//----------------------
if (d3 * d3 <= m_distance_tolerance_square * (dx * dx + dy * dy)) {
if (m_angle_tolerance < curve_angle_tolerance_epsilon) {
m_points.add(point_d(x23, y23));
return;
}
// Angle Condition
//----------------------
da1 = fabs(atan2(y4 - y3, x4 - x3) - atan2(y3 - y2, x3 - x2));
if (da1 >= pi)
da1 = 2 * pi - da1;
if (da1 < m_angle_tolerance) {
m_points.add(point_d(x2, y2));
m_points.add(point_d(x3, y3));
return;
}
if (m_cusp_limit != 0.0) {
if (da1 > m_cusp_limit) {
m_points.add(point_d(x3, y3));
return;
}
}
}
break;
case 2:
// p1,p3,p4 are collinear, p2 is significant
//----------------------
if (d2 * d2 <= m_distance_tolerance_square * (dx * dx + dy * dy)) {
if (m_angle_tolerance < curve_angle_tolerance_epsilon) {
m_points.add(point_d(x23, y23));
return;
}
// Angle Condition
//----------------------
da1 = fabs(atan2(y3 - y2, x3 - x2) - atan2(y2 - y1, x2 - x1));
if (da1 >= pi)
da1 = 2 * pi - da1;
if (da1 < m_angle_tolerance) {
m_points.add(point_d(x2, y2));
m_points.add(point_d(x3, y3));
return;
}
if (m_cusp_limit != 0.0) {
if (da1 > m_cusp_limit) {
m_points.add(point_d(x2, y2));
return;
}
}
}
break;
case 3:
// Regular case
//-----------------
if ((d2 + d3) * (d2 + d3) <= m_distance_tolerance_square * (dx * dx
+ dy * dy)) {
// If the curvature doesn't exceed the distance_tolerance value
// we tend to finish subdivisions.
//----------------------
if (m_angle_tolerance < curve_angle_tolerance_epsilon) {
m_points.add(point_d(x23, y23));
return;
}
// Angle & Cusp Condition
//----------------------
k = atan2(y3 - y2, x3 - x2);
da1 = fabs(k - atan2(y2 - y1, x2 - x1));
da2 = fabs(atan2(y4 - y3, x4 - x3) - k);
if (da1 >= pi)
da1 = 2 * pi - da1;
if (da2 >= pi)
da2 = 2 * pi - da2;
if (da1 + da2 < m_angle_tolerance) {
// Finally we can stop the recursion
//----------------------
m_points.add(point_d(x23, y23));
return;
}
if (m_cusp_limit != 0.0) {
if (da1 > m_cusp_limit) {
m_points.add(point_d(x2, y2));
return;
}
if (da2 > m_cusp_limit) {
m_points.add(point_d(x3, y3));
return;
}
}
}
break;
}
// Continue subdivision
//----------------------
recursive_bezier(x1, y1, x12, y12, x123, y123, x1234, y1234, level + 1);
recursive_bezier(x1234, y1234, x234, y234, x34, y34, x4, y4, level + 1);
}
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char to decimal Dirk Bruere at NeoPax <dirk.bruere@gmail.com> - 2011-05-05 01:43 +0100
Re: char to decimal Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2011-05-04 17:49 -0700
Re: char to decimal Ian Shef <invalid@avoiding.spam> - 2011-05-05 01:06 +0000
Re: char to decimal Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-05 20:03 +1200
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-05 07:03 -0400
Re: char to decimal Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-05-05 11:18 +0000
Re: char to decimal Patricia Shanahan <pats@acm.org> - 2011-05-05 06:11 -0700
Re: char to decimal Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-06 01:59 +1200
Re: char to decimal Mayeul <mayeul.marguet@free.fr> - 2011-05-05 16:53 +0200
Re: char to decimal Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-06 11:49 +1200
Re: char to decimal Mayeul <mayeul.marguet@free.fr> - 2011-05-06 08:46 +0200
Re: char to decimal Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-06 18:43 +1200
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-06 06:52 -0400
Re: char to decimal Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-05-06 11:39 +0000
Re: char to decimal Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-05-05 14:13 -0400
Re: char to decimal Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-06 11:49 +1200
Re: char to decimal Mayeul <mayeul.marguet@free.fr> - 2011-05-06 08:47 +0200
Re: char to decimal Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-06 18:43 +1200
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-06 06:54 -0400
Re: char to decimal Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2011-05-06 10:30 +0300
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-05 17:05 -0400
Re: char to decimal Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-05-05 14:56 +0000
Re: char to decimal Paul Cager <paul.cager@googlemail.com> - 2011-05-05 11:48 -0700
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-05 17:06 -0400
Re: char to decimal Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-05-05 21:28 +0000
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-05 17:32 -0400
Re: char to decimal Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-05-06 08:31 +0000
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-05 17:04 -0400
boolean to int : was char to decimal Jeff Higgins <jeff@invalid.invalid> - 2011-05-06 09:00 -0400
Re: boolean to int : was char to decimal Patricia Shanahan <pats@acm.org> - 2011-05-06 06:54 -0700
Re: boolean to int : was char to decimal markspace <-@.> - 2011-05-06 07:07 -0700
Re: boolean to int : was char to decimal markspace <-@.> - 2011-05-06 08:30 -0700
Re: boolean to int : was char to decimal Nigel Wade <nmw-news@ion.le.ac.uk> - 2011-05-06 15:35 +0100
Re: boolean to int : was char to decimal Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-06 19:12 +0200
Re: boolean to int : was char to decimal Jeff Higgins <jeff@invalid.invalid> - 2011-05-06 13:26 -0400
Re: boolean to int : was char to decimal Jeff Higgins <jeff@invalid.invalid> - 2011-05-06 21:25 -0400
Re: boolean to int : was char to decimal Jeff Higgins <jeff@invalid.invalid> - 2011-05-06 21:28 -0400
Re: boolean to int : was char to decimal Michael Wojcik <mwojcik@newsguy.com> - 2011-05-09 12:51 -0400
Re: boolean to int : was char to decimal Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-05-09 23:54 +0000
Re: boolean to int : was char to decimal Jeff Higgins <jeff@invalid.invalid> - 2011-05-09 20:51 -0400
Re: boolean to int : was char to decimal Michael Wojcik <mwojcik@newsguy.com> - 2011-05-10 11:20 -0400
Re: boolean to int : was char to decimal Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-10 13:47 +1200
Re: boolean to int : was char to decimal Michael Wojcik <mwojcik@newsguy.com> - 2011-05-10 11:02 -0400
Re: boolean to int : was char to decimal Lawrence D'Oliveiro <ldo@geek-central.gen.new_zealand> - 2011-05-11 14:05 +1200
Re: boolean to int : was char to decimal Jeff Higgins <jeff@invalid.invalid> - 2011-05-11 08:11 -0400
Re: char to decimal Dirk Bruere at NeoPax <dirk.bruere@gmail.com> - 2011-05-05 02:12 +0100
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-04 21:59 -0400
Re: char to decimal Dirk Bruere at NeoPax <dirk.bruere@gmail.com> - 2011-05-05 16:14 +0100
Re: char to decimal markspace <-@.> - 2011-05-05 11:20 -0700
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-05 17:10 -0400
Re: char to decimal Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-05-05 22:00 +0000
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-05 18:20 -0400
Re: char to decimal Dirk Bruere at NeoPax <dirk.bruere@gmail.com> - 2011-05-06 10:45 +0100
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-06 06:56 -0400
Re: char to decimal Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-05-06 11:48 +0000
Re: char to decimal Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-05-06 08:38 -0400
Re: char to decimal Michael Wojcik <mwojcik@newsguy.com> - 2011-05-06 09:47 -0400
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-06 12:02 -0400
Re: char to decimal Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-06 19:15 +0200
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-06 14:01 -0400
Re: char to decimal Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-06 20:07 +0200
Re: O/T linguistics (Was: char to decimal) Lew <noone@lewscanon.com> - 2011-05-06 15:28 -0400
Re: O/T linguistics Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-05-06 21:44 +0200
Re: char to decimal Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-05-06 23:57 +0000
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-06 12:00 -0400
Re: char to decimal Dirk Bruere at NeoPax <dirk.bruere@gmail.com> - 2011-05-06 18:29 +0100
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-06 14:02 -0400
Re: char to decimal Dirk Bruere at NeoPax <dirk.bruere@gmail.com> - 2011-05-07 01:09 +0100
Re: char to decimal Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-05-07 00:18 +0000
Re: char to decimal Lew <noone@lewscanon.com> - 2011-05-06 21:30 -0400
Re: char to decimal Roedy Green <see_website@mindprod.com.invalid> - 2011-05-04 22:03 -0700
Re: char to decimal "Nasser M. Abbasi" <nma@12000.org> - 2011-05-05 01:14 -0700
Re: char to decimal Dirk Bruere at NeoPax <dirk.bruere@gmail.com> - 2011-05-05 16:15 +0100
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