blob: 34db781045bba7ecab876c60cf0ec555bb679351 (
plain)
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
152
153
154
155
156
157
|
\begin{page}{HTXAdvPage4}{Patch and Paste}
\centerline{\fbox{{\tt \thispage}}}\newline
\begin{scroll}
A powerful \HyperName{} feature is
the ability to {\it replace}
part of a displayed page with another part
when an active area is clicked. The group commands
{\it patch} and {\it paste} offer this facility.
A {\it paste} region can appear anywhere
within a page or a {\it patch}. A {\it patch} region must be defined
outside a page definition.
We need a few objects to define the {\it paste}
region. These are a {\it name} with which to
refer to it, some way of specifying what it
is to be replaced by and a {\it trigger} for the
replacement. A {\it patch} is how we specify the
second of these objects.
The {\it patch} is generally a sequence of \HyperName{}
text.
If we want to have the option of returning to the original
(or ,indeed, proceeding to a {\it third} alternative)
we clearly must include a {\it paste} in the {\it patch}.
Let us start with a simple example. We wish to
have the word {\tt initial} somewhere on the page replaced by the
word {\tt final} at a click of a button.
Let us first define the {\it patch}. It will just contain
the word {\tt final}. Here is a definition of a
patch called {\tt patch1} (note that
the actual definition must be outside this page's definition).
\beginImportant
\newline
{\tt \\begin\{patch\}\{patch1\}} \newline
{\tt final}\newline
{\tt \\end\{patch\}}
\endImportant
We now define a {\it paste} region exactly where we
want the word {\tt initial} to appear.
\beginImportant
\newline
{\tt \\begin\{paste\}\{paste1\}\{patch1\}}\newline
{\tt initial}\newline
{\tt \\end\{paste\}}
\centerline{{\it results in}}
\begin{paste}{paste1}{patch1}
initial
\end{paste}
\endImportant
We have specified first the name of the {\it paste} region
which is {\tt paste1} and then the name of the
replacement {\it patch} which is {\tt patch1}.
Something is missing -- the trigger.
To include a trigger we write
\beginImportant
\newline
{\tt \\pastebutton\{paste1\}\{trigger\}
\centerline{{\it results in}}
\pastebutton{paste1}{trigger}
\endImportant
This new command {\tt \\pastebutton} displays the second argument
as an active area. The first argument specifies the {\it paste}
region it refers to. Clicking on {\tt trigger} above will
replace the word {\tt initial} with the word {\tt final}.
We can, if we like, include the {\tt \\pastebutton} in the {\it paste}
region.
Let us improve on the situation by providing a way
of going back to the original word {\tt initial} on the page.
The {\it patch} must itself include a {\it paste}.
What will the replacement {\it patch} for this new {\it paste}
be ? Well, we have to define a second {\it patch}
that contains all the stuff in the original {\it paste}
region. Here is the updated {\it patch} for the first replacement.
The {\tt \\MenuDotBitmap} macro is defined in {\bf util.ht}.
It displays a button bitmap.
This time we put the {\tt \\pastebutton}
inside the {\it paste}.
\beginImportant
\newline
{\tt \\begin\{patch\}\{Patch1\}}\newline
{\tt \\begin\{paste\}\{Paste2\}\{Patch2\}}\newline
{\tt \\pastebutton\{Paste2\}\{\\MenuDotBitmap\}}\newline
{\tt final}\newline
{\tt \\end\{paste\}}\newline
{\tt \\end\{patch\}}\newline
\endImportant
and the new {\tt Patch2} {\it patch}
\beginImportant
\newline
{\tt \\begin\{patch\}\{Patch2\}}\newline
{\tt \\begin\{paste\}\{Paste3\}\{Patch1\}}\newline
{\tt \\pastebutton\{Paste3\}\{\\MenuDotBitmap\}}\newline
{\tt initial}\newline
{\tt \\end\{paste\}}\newline
{\tt \\end\{patch\}}\newline
\endImportant
Remember that these {\it patch} definitons must
occur outside a {\tt \\begin\{page\} - \\end\{page\}} group.
What is left now is to define the starting {\it paste}
region.
\beginImportant
\newline
{\tt \\begin\{paste\}\{Paste1\}\{Patch1\}}\newline
{\tt \\pastebutton\{Paste1\}\{\\MenuDotBitmap\}}\newline
{\tt initial}\newline
{\tt \\end\{paste\}}
\centerline{{\it results in}}
\begin{paste}{Paste1}{Patch1}
\pastebutton{Paste1}{\MenuDotBitmap}
initial
\end{paste}
\endImportant
Clicking on the button above next to {\tt initial}
will replace the {\tt Paste1} region with
{\tt Patch1}. That {\it patch}
also contains a {\it paste} region ({\tt Paste2}).
Clicking on {\it its} button will put up
{\tt Patch2} which has a {\it paste} region ({\tt Paste3}).
Clicking on {\it its} button will put up {\tt Patch1}
again. In that way, we close the chain of replacements.
\end{scroll}
\beginmenu
\menulink{Next Page --- \Language{} paste-ins}{HTXAdvPage5}
\endmenu
\end{page}
\begin{patch}{patch1}
final
\end{patch}
\begin{patch}{Patch1}
\begin{paste}{Paste2}{Patch2}
\pastebutton{Paste2}{\MenuDotBitmap}
final
\end{paste}
\end{patch}
\begin{patch}{Patch2}
\begin{paste}{Paste3}{Patch1}
\pastebutton{Paste3}{\MenuDotBitmap}
initial
\end{paste}
\end{patch}
|
