1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
/* This file contains the concat method, which is a GNU extension to
libplot. As in Postscript, it left-multiplies the transformation matrix
from user coordinates to device coordinates by a specified matrix. That
is, it modifies the affine transformation from user coordinates to
device coordinates, by requiring that the transformation currently in
effect be be preceded by a specified affine transformation. */
/* Invoking concat causes the device-frame line width and the device-frame
size of the current font to be recomputed. */
#include "sys-defines.h"
#include "plot.h"
#include "extern.h"
int
#ifdef _HAVE_PROTOS
_g_fconcat (double m0, double m1, double m2, double m3, double m4, double m5)
#else
_g_fconcat (m0, m1, m2, m3, m4, m5)
double m0, m1, m2, m3, m4, m5;
#endif
{
double m[6];
double det;
if (!_plotter->open)
{
_plotter->error ("fconcat: invalid operation");
return -1;
}
m[0] = m0;
m[1] = m1;
m[2] = m2;
m[3] = m3;
m[4] = m4;
m[5] = m5;
_matrix_product (m, _plotter->drawstate->transform.m, _plotter->drawstate->transform.m);
/* following code as in space.c */
/* does map preserve axis directions? */
_plotter->drawstate->transform.axes_preserved =
(_plotter->drawstate->transform.m[1] == 0.0
&& _plotter->drawstate->transform.m[2] == 0.0);
#define FUZZ 0.0000001 /* potential roundoff error */
#define IS_ZERO(arg) (IS_ZERO1(arg) && IS_ZERO2(arg))
#define IS_ZERO1(arg) (fabs(arg) < FUZZ * DMAX(_plotter->drawstate->transform.m[0] * _plotter->drawstate->transform.m[0], _plotter->drawstate->transform.m[1] * _plotter->drawstate->transform.m[1]))
#define IS_ZERO2(arg) (fabs(arg) < FUZZ * DMAX(_plotter->drawstate->transform.m[2] * _plotter->drawstate->transform.m[2], _plotter->drawstate->transform.m[3] * _plotter->drawstate->transform.m[3]))
/* if row vectors are of equal length and orthogonal... */
if (IS_ZERO(_plotter->drawstate->transform.m[0] * _plotter->drawstate->transform.m[0]
+ _plotter->drawstate->transform.m[1] * _plotter->drawstate->transform.m[1]
- _plotter->drawstate->transform.m[2] * _plotter->drawstate->transform.m[2]
- _plotter->drawstate->transform.m[3] * _plotter->drawstate->transform.m[3])
&&
IS_ZERO(_plotter->drawstate->transform.m[0] * _plotter->drawstate->transform.m[2] +
_plotter->drawstate->transform.m[1] * _plotter->drawstate->transform.m[3]))
_plotter->drawstate->transform.uniform = true; /* map's scaling is uniform */
else
_plotter->drawstate->transform.uniform = false; /* map's scaling not uniform */
/* determine whether map involves a reflection, by computing determinant */
det = (_plotter->drawstate->transform.m[0] *
_plotter->drawstate->transform.m[3]
- (_plotter->drawstate->transform.m[1] *
_plotter->drawstate->transform.m[2]));
_plotter->drawstate->transform.nonreflection
= ((_plotter->flipped_y ? -1 : 1) * det >= 0);
/* This is a bit of a botch. We recompute device-frame line width, which
incidentally calls `endpath'. But we don't do so if the Plotter on
which this method is invoked is a MetaPlotter, since doing so would
cause a bogus LINEWIDTH op code to be emitted to the metafile, and a
MetaPlotter has no notion of device-frame line width anyway. */
if (_plotter->type != PL_META)
_plotter->flinewidth (_plotter->drawstate->line_width);
/* recompute font size in device coordinates */
_plotter->retrieve_font();
return 0;
}
|
