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
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
|
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<!-- XML file produced from file: manual.tex
using Hyperlatex v 2.6 (c) Otfried Cheong
on Emacs 21.3.1, Mon Nov 22 10:30:52 2004 -->
<head>
<title>Ipe Manual -- 6.5 Examples</title>
<style type="text/css">
.maketitle { align : center }
div.abstract { margin-left: 20%; margin-right: 10%; }
h3.abstract { align : center }
div.verse, div.quote, div.quotation {
margin-left : 10%;
margin-right : 10%;
}
</style>
<meta http-equiv="Content-Type"
content="text/html; charset=UTF-8">
</head>
<body bgcolor="#ffffe6">
<table width="100%" cellpadding=0 cellspacing=2><tr><td bgcolor="#99ccff"><img alt="" src="blank.png"></td><td bgcolor="#99ccff"><a href="manual_22.html"><img border="0" alt="6 Snapping" src="up.png"></a></td><td bgcolor="#99ccff"><a href="manual_26.html"><img border="0" alt="6.4 Interaction of the snapping modes" src="previous.png"></a></td><td align="center" bgcolor="#99ccff" width="100%"><b>6.5 Examples</b></td></tr></table>
<h2>6.5 Examples</h2>
<p>It takes some time and practice to feel fully at ease with the different
snapping modes, especially angular snapping. Here are some examples
showing what can be done with angular snapping.
<h4><a name="id1">Example 1:</a></h4>
We are given segments <i>s<sub>1</sub></i>, <i>s<sub>2</sub></i>, and <i>e</i>, and we want
to add the dashed vertical extensions through <i>p</i> and <i>q</i>.
<div align="center"><p>
<img alt="" src="example1.png">
</p></div>
<ul class="menu"><li>set <kbd>F4</kbd> and <kbd>F5</kbd> snapping on, go into <em>line</em> mode, and
reset axis system with <kbd>Shift-F1</kbd>,
<li>go near <i>p</i>, press <kbd>F1</kbd> and <kbd>F8</kbd> to set origin and
to turn on angular snap.
<li>go near <i>p'</i>, click left, and extend segment to <i>s<sub>2</sub></i>.
<li>go near <i>q</i>, press <kbd>F1</kbd> to reset origin, and draw second
extension in the same way.
</ul>
<h4><a name="id2">Example 2:</a></h4>
We are given the polygon <i>C</i>, and we want to draw the bracket
<i>b</i>, indicating its vertical extension.
<div align="center"><p>
<img alt="" src="example2.png">
</p></div>
<ul class="menu"><li>set <kbd>F4</kbd> and <kbd>F9</kbd> snapping on, go into <em>line</em> mode, reset
axis system, set snap angle to
90 degrees.
<li>go near <i>p</i>, press <kbd>F1</kbd> and <kbd>F8</kbd> to set origin and
angular snapping
<li>go to <i>x</i>, click left, extend segment to <i>y</i>, click left
<li>now we want to have <i>z</i> on a horizontal line through <i>q</i>:
go near <i>q</i>, and press <kbd>F1</kbd> and <kbd>F8</kbd> to reset origin
and to turn on angular snapping. Now both angular snapping modes are
on, the snap lines intersect in <i>z</i>.
<li>click left at <i>z</i>, goto <i>x</i> and press <kbd>F1</kbd>, goto
<i>t</i> and finish bracket.
</ul>
<h4><a name="id3">Example 3:</a></h4>
We want to draw the following "skyline". The only problem is to get
<i>q</i> horizontally aligned with <i>p</i>.
<div align="center"><p>
<img alt="" src="example3.png">
</p></div>
<ul class="menu"><li>draw the baseline using automatic angular snapping to get it
horizontal.
<li>place <i>p</i> with boundary snapping, draw the rectilinear curve up to
<i>r</i> with automatic angular snapping in
90 degrees mode.
<li>now go to <i>p</i> and press <kbd>F1</kbd> and <kbd>F8</kbd>. The snap lines
intersect in <i>q</i>. Click there, turn off angular snapping with
<kbd>Shift-F1</kbd>, and finish curve. The last point is placed with
boundary snapping.
</ul>
<h4><a name="id4">Example 4:</a></h4>
We want to draw a line through <i>p</i>, tangent to <i>C</i> in
<i>q</i>.
<div align="center"><p>
<img alt="" src="example4.png">
</p></div>
<ul class="menu"><li>with vertex snapping on, put origin at <i>p</i> with <kbd>F1</kbd>
<li>go to <i>q</i> and press <kbd>F2</kbd>. This puts the base direction from
<i>p</i> to <i>q</i>.
<li>set angular snapping with <kbd>F8</kbd> and draw line.
</ul>
<h4><a name="id5">Example 5:</a></h4>
We want to draw the following "windmill". The angle of the sector and
between sectors should be
30 degrees.
<div align="center"><p>
<img alt="" src="example5.png">
</p></div>
<ul class="menu"><li>set vertex snapping, snap angle to
30 degrees,
reset axis system with <kbd>Shift-F1</kbd>,
<li>with automatic angular snapping, draw a horizontal segment <i>pq</i>.
<li>go to <i>p</i>, place origin and turn on angular snapping with
<kbd>F1</kbd> and <kbd>F8</kbd>,
<li>duplicate segment with <kbd>d</kbd>, go to <i>q</i> and pick up <i>q</i> for
rotation (with Ctrl and the middle mouse button). Rotate until
segment falls on the next snap line.
<li>turn off angular snapping with <kbd>F8</kbd>. Choose arc mode, variant
"center & two points".
<li>go to <i>p</i>, click for center. Go to <i>q</i>, click for first
endpoint of arc, and at <i>r</i> for the second endpoint. Select all,
and group.
<li>turn angular snapping on again. Duplicate sector, and rotate by
60 degrees
using angular snapping.
<li>duplicate and rotate four more times.
</ul>
<h4><a name="id6">Example 6:</a></h4>
We want to draw a <i>c</i>-oriented polygon, where the angles between
successive segments are multiples of
30 degrees.
The automatic angular snapping mode makes this pretty easy, but there is a
little catch: How do we place the ultimate vertex such that it is at the
same time properly aligned to the penultimate and to the very first vertex?
<div align="center"><p>
<img alt="" src="example6.png">
</p></div>
<ul class="menu"><li>set snap angle to
30 degrees,
and turn on automatic angular snapping.
<li>click first vertex <i>p</i> and draw the polygon up to the penultimate
vertex <i>q</i>.
<li>it remains to place <i>r</i> such that it is in a legal position both
with respect to <i>q</i> and <i>p</i>. The automatic angular snapping
mode ensures the position with respect to <i>q</i>. We will use
angular snapping from <i>p</i> to get it right: Go near <i>p</i> and
turn on vertex snapping. Press <kbd>F1</kbd> to place the origin
at <i>p</i> and <kbd>F8</kbd> to turn on angular snapping. Now it is
trivial to place <i>r</i>.
</ul>
<hr />
<table width="100%" cellpadding=0 cellspacing=2><tr><td bgcolor="#99ccff"><img alt="" src="blank.png"></td><td bgcolor="#99ccff"><a href="manual_22.html"><img border="0" alt="6 Snapping" src="up.png"></a></td><td bgcolor="#99ccff"><a href="manual_26.html"><img border="0" alt="6.4 Interaction of the snapping modes" src="previous.png"></a></td><td align="center" bgcolor="#99ccff" width="100%"><b>6.5 Examples</b></td></tr></table></body></html>
|
