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back-trf.lua /size: 4842 b last modification: 2020-07-01 14:35
1if
 not
 modules
 then
 modules
 =
 {
 }
 end
 modules
 [
'
back-trf
'
]
 =
 {
2    version
   =
 1
.
001
,
3    comment
   =
 "
companion to back-ini.mkiv
"
,
4    author
    =
 "
Hans Hagen, PRAGMA-ADE, Hasselt NL
"
,
5    copyright
 =
 "
PRAGMA ADE / ConTeXt Development Team
"
,
6    license
   =
 "
see context related readme files
"
7}
8
9local
 sind
,
 cosd
,
 abs
 =
 math
.
sind
,
 math
.
cosd
,
 math
.
abs
10local
 insert
,
 remove
 =
 table
.
insert
,
 table
.
remove
11local
 unpack
 =
 unpack
12
13local
 context
           =
 context
14
15local
 formatters
        =
 string
.
formatters
16
17local
 scanners
          =
 tokens
.
scanners
18local
 scankeyword
       =
 scanners
.
keyword
19local
 scaninteger
       =
 scanners
.
integer
20local
 scannumber
        =
 scanners
.
number
21local
 scanstring
        =
 scanners
.
string
22
23local
 implement
         =
 interfaces
.
implement
24
25local
 nodepool
          =
 nodes
.
pool
26local
 savenode
          =
 nodepool
.
save
27local
 restorenode
       =
 nodepool
.
restore
28local
 setmatrixnode
     =
 nodepool
.
setmatrix
29local
 literalnode
       =
 nodepool
.
literal
 -- has to become some nodeinjection
30
31local
 stack
             =
 {
 }
32local
 restore
           =
 true
 -- false
33
34updaters
.
register
(
"
backend.update
"
,
function
(
)
35    savenode
      =
 nodepool
.
save
36    restorenode
   =
 nodepool
.
restore
37    setmatrixnode
 =
 nodepool
.
setmatrix
38    literalnode
   =
 nodepool
.
literal
 -- has to become some nodeinjection
39end
)
40
41local
 function
 stopsomething
(
)
42    local
 top
 =
 remove
(
stack
)
43    if
 top
 =
=
 false
 then
44        -- not wrapped
45    elseif
 top
 =
=
 true
 then
46        context
(
restorenode
(
)
)
47    elseif
 top
 then
48        context
(
setmatrixnode
(
unpack
(
top
)
)
)
 -- not really needed anymore
49        context
(
restorenode
(
)
)
50    else
51        -- nesting error
52    end
53end
54
55local
 function
 startrotation
(
)
56    local
 a
 =
 scannumber
(
)
57    if
 a
 =
=
 0
 then
58        insert
(
stack
,
false
)
59    else
60        local
 s
,
 c
 =
 sind
(
a
)
,
 cosd
(
a
)
61        if
 abs
(
s
)
 <
 0
.
000001
 then
62            s
 =
 0
 -- otherwise funny -0.00000
63        end
64        if
 abs
(
c
)
 <
 0
.
000001
 then
65            c
 =
 0
 -- otherwise funny -0.00000
66        end
67        context
(
savenode
(
)
)
68        context
(
setmatrixnode
(
c
,
s
,
-
s
,
c
)
)
69        insert
(
stack
,
restore
 and
 {
 c
,
 -
s
,
 s
,
 c
 }
 or
 true
)
70    end
71end
72
73implement
 {
 name
 =
 "
startrotation
"
,
 actions
 =
 startrotation
 }
74implement
 {
 name
 =
 "
stoprotation
"
,
  actions
 =
 stopsomething
 }
75
76local
 function
 startscaling
(
)
 -- at the tex end we use sx and sy instead of rx and ry
77    local
 rx
,
 ry
 =
 1
,
 1
78    while
 true
 do
79        if
 scankeyword
(
"
rx
"
)
 then
80            rx
 =
 scannumber
(
)
81        elseif
 scankeyword
(
"
ry
"
)
 then
82            ry
 =
 scannumber
(
)
83     -- elseif scankeyword("revert") then
84     --     local top = stack[#stack]
85     --     if top then
86     --         rx = top[1]
87     --         ry = top[4]
88     --     else
89     --         rx = 1
90     --         ry = 1
91     --     end
92        else
93            break
94        end
95    end
96    if
 rx
 =
=
 1
 and
 ry
 =
=
 1
 then
97        insert
(
stack
,
false
)
98    else
99        if
 rx
 =
=
 0
 then
100            rx
 =
 0
.
0001
101        end
102        if
 ry
 =
=
 0
 then
103            ry
 =
 0
.
0001
104        end
105        context
(
savenode
(
)
)
106        context
(
setmatrixnode
(
rx
,
0
,
0
,
ry
)
)
107        insert
(
stack
,
restore
 and
 {
 1
/
rx
,
 0
,
 0
,
 1
/
ry
 }
 or
 true
)
108    end
109end
110
111implement
 {
 name
 =
 "
startscaling
"
,
 actions
 =
 startscaling
 }
112implement
 {
 name
 =
 "
stopscaling
"
,
  actions
 =
 stopsomething
 }
113
114local
 function
 startmatrix
(
)
 -- rx sx sy ry  -- tx, ty
115    local
 rx
,
 sx
,
 sy
,
 ry
 =
 1
,
 0
,
 0
,
 1
116    while
 true
 do
117            if
 scankeyword
(
"
rx
"
)
 then
 rx
 =
 scannumber
(
)
118        elseif
 scankeyword
(
"
ry
"
)
 then
 ry
 =
 scannumber
(
)
119        elseif
 scankeyword
(
"
sx
"
)
 then
 sx
 =
 scannumber
(
)
120        elseif
 scankeyword
(
"
sy
"
)
 then
 sy
 =
 scannumber
(
)
121        else
   break
 end
122    end
123    if
 rx
 =
=
 1
 and
 sx
 =
=
 0
 and
 sy
 =
=
 0
 and
 ry
 =
=
 1
 then
124        insert
(
stack
,
false
)
125    else
126        context
(
savenode
(
)
)
127        context
(
setmatrixnode
(
rx
,
sx
,
sy
,
ry
)
)
128        insert
(
stack
,
store
 and
 {
 -
rx
,
 -
sx
,
 -
sy
,
 -
ry
 }
 or
 true
)
129    end
130end
131
132implement
 {
 name
 =
 "
startmatrix
"
,
 actions
 =
 startmatrix
 }
133implement
 {
 name
 =
 "
stopmatrix
"
,
  actions
 =
 stopsomething
 }
134
135local
 function
 startmirroring
(
)
136    context
(
setmatrixnode
(
-1
,
0
,
0
,
1
)
)
137end
138
139implement
 {
 name
 =
 "
startmirroring
"
,
 actions
 =
 startmirroring
 }
140implement
 {
 name
 =
 "
stopmirroring
"
,
  actions
 =
 startmirroring
 }
 -- not: stopsomething
141
142-- this could also run on top of pack-rul ... todo
143
144-- local function startclipping()
145--  -- context(savenode())
146--     context(literalnode("origin",formatters["q 0 w %s W n"](scanstring())))
147-- end
148--
149-- local function stopclipping()
150--  -- context(restorenode())
151--     context(literalnode("Q"))
152-- end
153
154local
 function
 startclipping
(
)
155    context
(
savenode
(
)
)
156    context
(
literalnode
(
"
origin
"
,
formatters
[
"
0 w %s W n
"
]
(
scanstring
(
)
)
)
)
157end
158
159local
 function
 stopclipping
(
)
160    context
(
restorenode
(
)
)
161end
162
163implement
 {
 name
 =
 "
startclipping
"
,
 actions
 =
 startclipping
 }
164implement
 {
 name
 =
 "
stopclipping
"
,
  actions
 =
 stopclipping
 }
165
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