2000-11-16 Henning Meier-Geinitz <hmg@gmx.de>

* TODO: Entries about SANE_DEFAULT_DEVICE and DBG output.

	* src/xscanimage.c: Added suport for DBG messages. Added only a
	  few messages including a more verbose output when xscanimage
	  can't find any devices. Added support for SANE_DEFAULT_DEVICE.

	* doc/xscanimage.man: Documented support for SANE_DEFAULT_DEVICE and
	  SANE_DEBUG_XSCANIMAGE.

TODO

@@ -1,4 +1,4 @@
-TODO (2000-11-14)
+TODO (2000-11-16)
 
 ******** todo ********
 
@@ -52,6 +52,10 @@ TODO (2000-11-14)
     is wrong, as we have to specify one value for each channel (i.e for a
     24bit RGB pic we must specify 8,8,8, see TIFF6.0 spec, [...]
 
+  * Add support for SANE_DEFAULT_DEVICE to xcam (see (x)scanimage).
+
+  * Add/improve debug output for xscanimage and xcam.
+
 ******** done ********
 
   * xcam: if the user quits xcam by the window manager, the process isn't

doc/xscanimage.man

@@ -1,4 +1,4 @@
-.TH xscanimage 1 "11 Aug 2000"
+.TH xscanimage 1 "16 Nov 2000"
 .IX xscanimage
 .SH NAME
 xscanimage - scan an image
@@ -29,10 +29,11 @@ Now Easy) interface.  The list of available devices depends on
 installed hardware and configuration.  When invoked without an
 explicit devicename argument,
 .B xscanimage
-presents a dialog listing all known and available devices.  To access
-an available device that is not known to the system, the devicename
-must be specified explicitly. The format of devicename is
-backendname:devicefile (eg umax:/dev/sga).
+presents a dialog listing of all known and available devices.  To access an
+available device that is not known to the system, the devicename must be
+specified explicitly.  Another way to select a device is to set the
+environment variable SANE_DEFAULT_DEVICE to devicename.  The format of
+devicename is backendname:devicefile (eg umax:/dev/sga).
 .SH RUNNING UNDER THE GIMP
 To run
 .B xscanimage
@@ -97,6 +98,24 @@ The
 .B --sync
 flag requests a synchronous connection with the X11 server.  This is for
 debugging purposes only.
+.SH ENVIRONMENT
+.TP
+.B SANE_DEFAULT_DEVICE
+The default device-name. Example: SANE_DEFAULT_DEVICE="hp:/dev/scanner"
+.TP
+.B SANE_DEBUG_XSCANIMAGE
+This environment variable controls the debug level xscanimage.  Higher
+debug levels increase the verbosity of the output.
+
+              Value  Descsription
+              0      print fatal errors
+              1      print errors
+              2      print warnings
+              3      print information messages
+              4      print everything
+
+              Example:
+              SANE_DEBUG_XSCANIMAGE=3
 .SH FILES
 .TP
 .I $HOME/.sane/xscanimage/xscanimage.rc

src/xscanimage.c

@@ -45,6 +45,9 @@
 #include <sane/saneopts.h>
 #include "../include/sane/sanei.h"
 
+#define BACKEND_NAME xscanimage
+#include "../include/sane/sanei_debug.h"
+
 #include <progress.h>
 #include <preferences.h>
 #include <preview.h>
@@ -64,6 +67,12 @@
 #define GIMP_ENABLE_COMPAT_CRUFT
 #include <libgimp/gimp.h>
 
+#define DBG_fatal 0
+#define DBG_error 1
+#define DBG_warning 2
+#define DBG_info 3
+#define DBG_debug 4
+
 static void query (void);
 static void run (char *name, int nparams, GParam * param,
 		 int *nreturn_vals, GParam ** return_vals);
@@ -468,6 +477,7 @@ quit_xscan (void)
   if (scan_win.mode == SANE_GIMP_EXTENSION)
     gimp_quit ();
 #endif
+  DBG(DBG_debug, "xscanimage exiting.\n");
   exit (0);
 }
 
@@ -1600,6 +1610,7 @@ init (int argc, char **argv)
 {
   char filename[PATH_MAX];
   struct stat st;
+  const char *defdevname;
 
   gtk_init (&argc, &argv);
 #ifdef HAVE_LIBGIMP_GIMP_H
@@ -1659,6 +1670,21 @@ init (int argc, char **argv)
 	  seldev = 0;
 	}
     }
+  else if ((defdevname = getenv("SANE_DEFAULT_DEVICE")) != NULL)
+    {
+      static SANE_Device dev;
+      static const SANE_Device *device_list[] = { &dev, 0 };
+
+      memset (&dev, 0, sizeof (dev));
+      dev.name   = defdevname;
+      dev.vendor = "Unknown";
+      dev.type   = "unknown";
+      dev.model  = "unknown";
+      
+      devlist = device_list;
+      seldev = 0;
+      DBG (DBG_info, "default device is `%s'\n", defdevname);
+    }
 
   if (seldev < 0)
     sane_get_devices (&devlist, SANE_FALSE);
@@ -1701,7 +1727,11 @@ interface (int argc, char **argv)
 	}
       else
 	{
-	  fprintf (stderr, "%s: no devices available.\n", prog_name);
+	  DBG (DBG_fatal, "No scanners were identified. If you were expecting something\n"
+	       "          different, check that the scanner is plugged in, turned on and\n"
+	       "          detected by the find-scanner tool (if appropriate). Please read\n"
+	       "          the documentation which came with this software (README, FAQ,\n"
+	       "          manpages).\n");
 	  quit_xscan ();
 	}
     }
@@ -1713,6 +1743,9 @@ interface (int argc, char **argv)
 int
 main (int argc, char **argv)
 {
+  DBG_INIT();
+  DBG(DBG_error, "xscanimage (version: %s, package: %s) starting\n", VERSION,
+      PACKAGE);
   scan_win.mode = STANDALONE;
   gtk_quit_flag = 0;
   prog_name = strrchr (argv[0], '/');