1 .\" gsc.4 - manual page for the scanner device driver `gsc'
4 .\" Copyright (c) 1995 Gunther Schadow. All rights reserved.
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31 .\" $FreeBSD: src/share/man/man4/man4.i386/gsc.4,v 1.12.2.7 2001/12/17 11:30:13 ru Exp $
38 .Nd a device driver for a handy scanner
42 .Cd Minor number bits: Ar uu d g p ...
43 .Bl -tag -width "uu " -compact -offset indent
66 character device driver currently handles only the
67 Genius GS-4500 handy scanner.
68 It operates in pure DMA modes, although
69 the hardware could be set up to work with irq.
71 documentation nor experience in writing interrupt driven device
74 The device can operate at four different
78 It produces a simple bitmap with the most significant
80 The driver can optionally output the famous and
81 likely simple portable bitmap file format
84 Thus the scans can easily processed by any graphic package around
88 only to name some of them ...). In
91 bit which is set means a black pixel because the scanner detects black
92 points on white paper.
93 On the other hand, because pnm format describes
94 intensities of electron beams in video screens a set bit in
96 mode means a white pixel.
100 of the output bitmap is fixed as given by the
104 of the bitmap must be
107 mode since the driver must know at what time the
110 With this feature you are able to
111 directly copy the scanner output into a pbm file with
113 Of course you can obtain a similar effect by using
121 output mode is not yet implemented into the driver.
122 It is even questionable if external programs would not do this job
123 better thereby not counting to the size of the kernel.
125 do not know of tools which produce a graymap from a halftone bitmap.
127 The ioctl requests that are served by
130 There is a utility, called
132 that provides access to these
133 requests from within shell.
135 .It Dv GSC_SRES Vt int
139 If this call is made after the first
140 read access to the device there will be no effect unless the device is
141 closed and opened again.
142 .It Dv GSC_GRES Vt int
143 Get current resolution in dots per inch (dpi).
144 .It Dv GSC_SRESSW Vt void
145 Set resolution value from selector switch.
146 The driver must be in an
147 open though untouched state otherwise the request will fail and
151 .It Dv GSC_SWIDTH Vt int
155 Actually, this is an alternative
156 way of setting the resolution, since any allowed resolution matches
158 Allowed are listed in the table below.
159 .Bl -tag -width resolution -compact -offset indent
178 Values which are not reported in the above table will cause the ioctl
184 As you can see, there are width values > 1696.
185 This does, however, not
186 mean that you can obtain scanned lines longer than the width of your
187 scanner or by higher resolutions.
188 Actually, the resolution is selected
189 by only by the hardware switch.
190 Any line that is longer than what is
191 defined for the actual resolution will be undefined (usually white) on
192 the right part that is exceeding the standard line.
193 .It Dv GSC_GWIDTH Vt int
194 Get current width of the bitmap in pixels.
195 .It Dv GSC_SHEIGHT Vt int
202 a limit on the amount of lines scannable after the first read
204 When the limit is reached read will return 0. However, the
205 device is turned off only when a close is performed (either
206 explicitly or implicitly on exit of the calling process).
207 .It Dv GSC_GHEIGHT Vt int
208 Get the current height of the bitmap.
209 .It Dv GSC_SBLEN Vt int
210 Set the length of the buffer used internally to do the DMA transfer.
211 The buffer length is supplied in lines of the bitmap.
213 size limit is (currently) 0x3000 bytes the maximum number of lines
214 allowed will vary with the width of each line.
216 checked before it overwrites the current value and passes an
221 However, since the bitmap width can change
222 after a buffer length was selected a read request may fail with
224 if the buffer length turns out too high.
225 It is generally wise to
226 choose long buffers rather than go save in order to obtain better
228 .It Dv GSC_GBLEN Vt int
229 Get the current buffer length in lines.
230 .It Dv GSC_SBTIME Vt int
231 Set the timeout for the completion of reading one buffer.
233 handy scanner is a human/computer interface timeout values are usually
234 higher than those of a flat scanner.
235 Default is 15 seconds.
237 timeout is reached the read operation will fail with
240 the timeout timer starts anew for each buffer to be read and thus does
241 not cause you to scan faster for longer images.
242 BLEN/BTIME is similar
245 .It Dv GSC_GBTIME Vt int
246 Get the current buffer timeout.
249 All ioctl requests that modify a parameter except
252 have an effect on an ongoing scan process, i.e. after the first read
253 request that follows open.
254 You must close the device and open it again
255 for the new selections to take effect.
256 Consequently, the selections
257 are not reset when you close or open the device.
259 Similarly, requests that read a value do not report the value that is
260 used for the ongoing scan process.
261 The values needed during the scan
262 process are saved when it starts and thus are not accessed by ioctl
265 The BTIME value does, however, have an immediate effect on the ongoing
267 Thus the timeout can for example be set to long until the user
268 starts scanning. It can then be set to a short amount to react
269 (nearly) immediately when the user stops.
270 Note that the user should be
271 left time to at least fill one buffer without having to haste.
277 mode selection is done by the
278 minor number not by ioctl requests.
282 height of the bitmap will have no effect.
284 .Bl -tag -width /dev/gsc0pd
288 output, has minor number 0.
295 GSCDEBUG option was given at compile time, has minor number 32.
297 device node for output in
299 file format, has minor number 8.
305 mode, has minor number 40.
308 .Bd -literal -offset indent
309 dd if=/dev/gsc0 of=rawfile bs=(width/8) count=(height)
311 cat /dev/gsc0p > pbmfile
316 When you define this name as an `option' in the kernel configuration
317 you can get debug output if you access the driver with a minor number
318 whose debug bit (i.e. bit 5 out of 7) is set.
323 .Xr pbmtopgm 1 Pq Pa pkgsrc/graphics/netpbm ,
331 .Xr pbm 5 Pq Pa pkgsrc/graphics/netpbm ,
332 .Xr pnm 5 Pq Pa pkgsrc/graphics/netpbm
334 .An Gunther Schadow Aq gusw@fub46.zedat.fu-berlin.de
336 Even though the scanner device has a little switch by which you should
337 be able to select one of the four resolution modes, I could not yet
338 determine how to read its status.
339 Unless this is not fixed the driver
340 depends on the value passed by means of
343 what is selected by the hardware.