1LIB2648(3X) LIB2648(3X)
2
6 lib2648 - subroutines for the HP 2648 graphics terminal
7
9 #include <stdio.h>
10 typedef char *bitmat;
12 FILE *trace;
13 cc file.c -l2648
15
17 Lib2648 is a general purpose library of subroutines useful for interac‐
18 tive graphics on the Hewlett-Packard 2648 graphics terminal. To use it
19 you must call the routine ttyinit() at the beginning of execution, and
20 done() at the end of execution. All terminal input and output must go
21 through the routines rawchar, readline, outchar, and outstr.
22 Lib2648 does the necessary ^E/^F handshaking if getenv(``TERM'')
24 returns ``hp2648'', as it will if set by tset(1). Any other value,
25 including for example ``2648'', will disable handshaking.
26 Bit matrix routines are provided to model the graphics memory of the
28 2648. These routines are generally useful, but are specifically useful
29 for the update function which efficiently changes what is on the screen
30 to what is supposed to be on the screen. The primative bit matrix rou‐
31 tines are newmat, mat, and setmat.
32 The file trace, if non-null, is expected to be a file descriptor as
34 returned by fopen. If so, lib2648 will trace the progress of the out‐
35 put by writing onto this file. It is provided to make debugging output
36 feasible for graphics programs without messing up the screen or the
37 escape sequences being sent. Typical use of trace will include:
38 switch (argv[1][1]) {
39 case 'T':
40 trace = fopen("trace", "w");
41 break;
42 ...
43 if (trace)
44 fprintf(trace, "x is %d, y is %s\n", x, y);
45 ...
46 dumpmat("before update", xmat);
47
49 agoto(x, y)
50 Move the alphanumeric cursor to position (x, y), measured from
51 the upper left corner of the screen.
52 aoff() Turn the alphanumeric display off.
54 aon() Turn the alphanumeric display on.
56 areaclear(rmin, cmin, rmax, cmax)
58 Clear the area on the graphics screen bordered by the four argu‐
59 ments. In normal mode the area is set to all black, in inverse
60 video mode it is set to all white.
61 beep() Ring the bell on the terminal.
63 bitcopy(dest, src, rows, cols) bitmat dest, src;
65 Copy a rows by cols bit matrix from src to (user provided) dest.
66 cleara()
68 Clear the alphanumeric display.
69 clearg()
71 Clear the graphics display. Note that the 2648 will only clear
72 the part of the screen that is visible if zoomed in.
73 curoff()
75 Turn the graphics cursor off.
76 curon()
78 Turn the graphics cursor on.
79 dispmsg(str, x, y, maxlen) char *str;
81 Display the message str in graphics text at position (x, y).
82 The maximum message length is given by maxlen, and is needed for
83 dispmsg to know how big an area to clear before drawing the mes‐
84 sage. The lower left corner of the first character is at (x,
85 y).
86 done() Should be called before the program exits. Restores the tty to
88 normal, turns off graphics screen, turns on alphanumeric screen,
89 flushes the standard output, etc.
90 draw(x, y)
92 Draw a line from the pen location to (x, y). As with all graph‐
93 ics coordinates, (x, y) is measured from the bottom left corner
94 of the screen. (x, y) coordinates represent the first quadrant
95 of the usual Cartesian system.
96 drawbox(r, c, color, rows, cols)
98 Draw a rectangular box on the graphics screen. The lower left
99 corner is at location (r, c). The box is rows rows high and
100 cols columns wide. The box is drawn if color is 1, erased if
101 color is 0. (r, c) absolute coordinates represent row and col‐
102 umn on the screen, with the origin at the lower left. They are
103 equivalent to (x, y) except for being reversed in order.
104 dumpmat(msg, m, rows, cols) char *msg; bitmat m;
106 If trace is non-null, write a readable ASCII representation of
107 the matrix m on trace. Msg is a label to identify the output.
108 emptyrow(m, rows, cols, r) bitmat m;
110 Returns 1 if row r of matrix m is all zero, else returns 0.
111 This routine is provided because it can be implemented more
112 efficiently with a knowledge of the internal representation than
113 a series of calls to mat.
114 error(msg) char *msg;
116 Default error handler. Calls message(msg) and returns. This is
117 called by certain routines in lib2648. It is also suitable for
118 calling by the user program. It is probably a good idea for a
119 fancy graphics program to supply its own error procedure which
120 uses setjmp(3) to restart the program.
121 gdefault()
123 Set the terminal to the default graphics modes.
124 goff() Turn the graphics display off.
126 gon() Turn the graphics display on.
128 koff() Turn the keypad off.
130 kon() Turn the keypad on. This means that most special keys on the
132 terminal (such as the alphanumeric arrow keys) will transmit an
133 escape sequence instead of doing their function locally.
134 line(x1, y1, x2, y2)
136 Draw a line in the current mode from (x1, y1) to (x2, y2). This
137 is equivalent to move(x1, y1); draw(x2, y2); except that a bug
138 in the terminal involving repeated lines from the same point is
139 compensated for.
140 lowleft()
142 Move the alphanumeric cursor to the lower left (home down) posi‐
143 tion.
144 mat(m, rows, cols, r, c) bitmat m;
146 Used to retrieve an element from a bit matrix. Returns 1 or 0
147 as the value of the [r, c] element of the rows by cols matrix m.
148 Bit matrices are numbered (r, c) from the upper left corner of
149 the matrix, beginning at (0, 0). R represents the row, and c
150 represents the column.
151 message(str) char *str;
153 Display the text message str at the bottom of the graphics
154 screen.
155 minmax(g, rows, cols, rmin, cmin, rmax, cmax) bitmat g;
157 int *rmin, *cmin, *rmax, *cmax;
158 Find the smallest rectangle that contains all the 1 (on) ele‐
159 ments in the bit matrix g. The coordinates are returned in the
160 variables pointed to by rmin, cmin, rmax, cmax.
161 move(x, y)
163 Move the pen to location (x, y). Such motion is internal and
164 will not cause output until a subsequent sync().
165 movecurs(x, y)
167 Move the graphics cursor to location (x, y).
168 bitmat newmat(rows, cols)
170 Create (with malloc(3)) a new bit matrix of size rows by cols.
171 The value created (e.g. a pointer to the first location) is
172 returned. A bit matrix can be freed directly with free.
173 outchar(c) char c;
175 Print the character c on the standard output. All output to the
176 terminal should go through this routine or outstr.
177 outstr(str) char *str;
179 Print the string str on the standard output by repeated calls to
180 outchar.
181 printg()
183 Print the graphics display on the printer. The printer must be
184 configured as device 6 (the default) on the HPIB.
185 char rawchar()
187 Read one character from the terminal and return it. This rou‐
188 tine or readline should be used to get all input, rather than
189 getchar(3).
190 rboff()
192 Turn the rubber band line off.
193 rbon() Turn the rubber band line on.
195 char *rdchar(c) char c;
197 Return a readable representation of the character c. If c is a
198 printing character it returns itself, if a control character it
199 is shown in the ^X notation, if negative an apostrophe is
200 prepended. Space returns ^`, rubout returns ^?.
201 NOTE: A pointer to a static place is returned. For this reason,
203 it will not work to pass rdchar twice to the same
204 fprintf/sprintf call. You must instead save one of the values
205 in your own buffer with strcpy.
206 readline(prompt, msg, maxlen) char *prompt, *msg;
208 Display prompt on the bottom line of the graphics display and
209 read one line of text from the user, terminated by a newline.
210 The line is placed in the buffer msg, which has size maxlen
211 characters. Backspace processing is supported.
212 setclear()
214 Set the display to draw lines in erase mode. (This is reversed
215 by inverse video mode.)
216 setmat(m, rows, cols, r, c, val) bitmat m;
218 The basic operation to store a value in an element of a bit
219 matrix. The [r, c] element of m is set to val, which should be
220 either 0 or 1.
221 setset()
223 Set the display to draw lines in normal (solid) mode. (This is
224 reversed by inverse video mode.)
225 setxor()
227 Set the display to draw lines in exclusive or mode.
228 sync() Force all accumulated output to be displayed on the screen.
230 This should be followed by fflush(stdout). The cursor is not
231 affected by this function. Note that it is normally never nec‐
232 essary to call sync, since rawchar and readline call sync() and
233 fflush(stdout) automatically.
234 togvid()
236 Toggle the state of video. If in normal mode, go into inverse
237 video mode, and vice versa. The screen is reversed as well as
238 the internal state of the library.
239 ttyinit()
241 Set up the terminal for processing. This routine should be
242 called at the beginning of execution. It places the terminal in
243 CBREAK mode, turns off echo, sets the proper modes in the termi‐
244 nal, and initializes the library.
245 update(mold, mnew, rows, cols, baser, basec) bitmat mold, mnew;
247 Make whatever changes are needed to make a window on the screen
248 look like mnew. Mold is what the window on the screen currently
249 looks like. The window has size rows by cols, and the lower
250 left corner on the screen of the window is [baser, basec].
251 Note: update was not intended to be used for the entire screen.
252 It would work but be very slow and take 64K bytes of memory just
253 for mold and mnew. It was intended for 100 by 100 windows with
254 objects in the center of them, and is quite fast for such win‐
255 dows.
256 vidinv()
258 Set inverse video mode.
259 vidnorm()
261 Set normal video mode.
262 zermat(m, rows, cols) bitmat m;
264 Set the bit matrix m to all zeros.
265 zoomn(size)
267 Set the hardware zoom to value size, which can range from 1 to
268 15.
269 zoomoff()
271 Turn zoom off. This forces the screen to zoom level 1 without
272 affecting the current internal zoom number.
273 zoomon()
275 Turn zoom on. This restores the screen to the previously speci‐
276 fied zoom size.
277
279 The routine error is called when an error is detected. The only error
280 currently detected is overflow of the buffer provided to readline.
281 Subscripts out of bounds to setmat return without setting anything.
283
285 /usr/lib/lib2648.a
286
288 fed(1)
289
291 Mark Horton
292
294 This library is not supported. It makes no attempt to use all of the
295 features of the terminal, only those needed by fed. Contributions from
296 users will be accepted for addition to the library.
297 The HP 2648 terminal is somewhat unreliable at speeds over 2400 baud,
299 even with the ^E/^F handshaking. In an effort to improve reliability,
300 handshaking is done every 32 characters. (The manual claims it is only
301 necessary every 80 characters.) Nonetheless, I/O errors sometimes
302 still occur.
303 There is no way to control the amount of debugging output generated on
305 trace without modifying the source to the library.
3064.2 Berkeley Distribution May 27, 1986 LIB2648(3X)