From a8982973a30709b358876498572df8d2e96ef5cf Mon Sep 17 00:00:00 2001
From: Michael Gernoth <michael@gernoth.net>
Date: Sun, 6 Jun 2010 02:09:32 +0200
Subject: [PATCH] add command "screen" to save a screenshot

---
 rigol.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 90 insertions(+), 1 deletion(-)

diff --git a/rigol.c b/rigol.c
index 24a4a10..e7497ac 100644
--- a/rigol.c
+++ b/rigol.c
@@ -13,8 +13,12 @@ rmmod uhci_hcd; modprobe uhci_hcd
 #include <stdio.h>
 #include <string.h>
 #include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <signal.h>
+#include <time.h>
 
 #include <readline/readline.h>
 #include <readline/history.h>
@@ -293,7 +297,73 @@ void do_get_buf (struct usb_dev_handle *sc)
 	sendscpi (sc, ":TIM:OFFSET 0", NULL, 0);
 }
 
+void do_get_screen(struct usb_dev_handle *sc)
+{
+	unsigned char screen[320*234];
+	unsigned char screen_conv[320*234*3];
+	unsigned char lut[256][3];
+	time_t lt;
+	char filename[256];
+	int i;
+	int l;
+	FILE *fp;
+	pid_t display;
+
+	/* Hide "RMT" from screen */
+	l = sendscpi(sc, ":KEY:LOCK DISABLE", NULL, 0); 
+	usleep(20000);
+
+	l = sendscpi(sc, ":LCD:DATA?", screen, sizeof(screen));
+
+	if (l != sizeof(screen)) {
+		printf ("hmm. didnt' get %d bytes, but %d\n\n", sizeof(screen), l); 
+	}
 
+	for(i = 0; i < 256; i++) {
+		lut[i][0] = ((i >> 6) * 0x55);
+		lut[i][1] = ((((i >> 3) & 7) * 0x49) >> 1);
+		lut[i][2] = (((i & 7) * 0x49) >> 1);
+	}
+
+	for(i = 0; i < sizeof(screen_conv); i += 3) {
+		screen_conv[i] = lut[screen[i/3]][0];
+		screen_conv[i+1] = lut[screen[i/3]][1];
+		screen_conv[i+2] = lut[screen[i/3]][2];
+	}
+
+	lt = time(NULL);
+	strftime(filename, sizeof(filename), "screen_%Y%m%d-%H%M%S.ppm", localtime(&lt));
+
+	fp = fopen (filename, "w");
+	fprintf(fp, "P6\n320 234\n255\n");
+	fwrite(screen_conv, sizeof(screen_conv), 1, fp);
+	fclose (fp); 
+
+	printf("Waveform saved as %s\n", filename);
+
+	display = fork();
+	switch(display) {
+		case 0:
+			execlp("display", "display", filename, NULL);
+			exit(0);
+			break;
+		case -1:
+			perror("fork");
+			break;
+		default:
+			break;
+	}
+}
+
+void child_reaper(int sig)
+{
+	pid_t child;
+
+	do {
+		child = waitpid(-1, NULL, WNOHANG);
+	} while(child > 0);
+	
+}
 
 int main(int argc, char **argv) 
 {
@@ -301,6 +371,8 @@ int main(int argc, char **argv)
 	char *scpi;
 	unsigned char *buff;
 	int l;
+	struct sigaction act;
+
 	//Init libusb
 	usb_init();
 	//Locate and open the scope
@@ -314,6 +386,19 @@ int main(int argc, char **argv)
 	//Initialize scope
 	initscope(sc);
 	buff = malloc (1024*1024); 
+	if (buff == NULL) {
+		perror("malloc");
+		exit(EXIT_FAILURE);
+	}
+
+	bzero(&act, sizeof(act));
+	act.sa_handler = child_reaper;
+	act.sa_flags = SA_NOCLDSTOP|SA_RESTART;
+	if (sigaction(SIGCHLD, &act, NULL) == -1) {
+		perror("sigaction");
+		exit(EXIT_FAILURE);
+	}
+
 	while (1) {
 		scpi = readline ("> ");
 
@@ -330,10 +415,14 @@ int main(int argc, char **argv)
 			do_plot (sc);
 			continue;
 		}
-		if (strncmp (scpi, "databuf", 4) == 0) {
+		if (strncmp (scpi, "databuf", 7) == 0) {
 			do_get_buf (sc);
 			continue;
 		}
+		if (strncmp (scpi, "screen", 6) == 0) {
+			do_get_screen (sc);
+			continue;
+		}
 
 		l = strlen (scpi); 
 		//printf ("got buf(%d): ", l); 
-- 
2.39.5