Fading now works

TODO

@@ -2,5 +2,5 @@
 #List devices
 #Query backlight percentage (get)
 xbacklight compat option (-get/-set/-inc/-dec/-help/-time/-steps)
-allow fade in and fade out
+#allow fade in and fade out
 a lot of cleanup

include/cmd.h

@@ -48,6 +48,8 @@ struct arg_values{
 	//How many seconds to transition
 	int fade_duration;
 
+	int fade_steps;
+
 	unsigned char operation;
 };
 

makefile

@@ -55,9 +55,9 @@ $(foreach dir,$(SOURCE_DIRS),$(eval $(call GENERATE_OBJECTS,$(dir))))
 $(OBJECTS): | $(OBJDIR) $(DEPDIR)
 
 $(OBJDIR):
-	mkdir "$@"
+	mkdir -p "$@"
 $(DEPDIR):
-	mkdir "$@"
+	mkdir -p "$@"
 
 .PHONY: clean
 clean:

src/cmd.c

@@ -27,6 +27,8 @@
 #define GET_SHORT_OPT    "-g"
 #define FADE_LONG_OPT    "--fade"
 #define FADE_SHORT_OPT   "-f"
+#define STEPS_LONG_OPT   "--steps"
+#define STEPS_SHORT_OPT  "-s"
 #define DEVICE_LONG_OPT  "--device"
 #define DEVICE_SHORT_OPT "-d"
 #define LIST_LONG_OPT    "--list"
@@ -39,7 +41,8 @@
 
 struct cmd_arg rexbacklight_args[] = {
 	{DEVICE_LONG_OPT, DEVICE_SHORT_OPT, "select which device to control"},
-	{FADE_LONG_OPT,   FADE_SHORT_OPT,   "TODO: change brightness over time interval"},
+	{FADE_LONG_OPT,   FADE_SHORT_OPT,   "change brightness over time interval"},
+	{STEPS_LONG_OPT,  STEPS_SHORT_OPT,  "number of steps over which to fade"},
 	{GET_LONG_OPT,    GET_SHORT_OPT,    "print current brightness level to stdout"},
 	{LIST_LONG_OPT,   LIST_SHORT_OPT,   "print device names to stdout and exit"},
 	{HELP_LONG_OPT,   HELP_SHORT_OPT,   "print this help message and exit"}
@@ -54,24 +57,28 @@ void free_cmd_args(struct arg_values* a){
 	free(a->next);
 }
 
-#define CHECK_NEXT_ARG(rval) \
+#define CHECK_NEXT_ARG() \
 	do{ \
 		if(i == argc - 1){ \
 			fprintf(stderr, "Missing argument to '%s'\n\n", argv[i]); \
 			free_cmd_args(&ret); \
-			usage(rval); \
+			usage(RETVAL_MISSING_OPTION); \
 		} \
 	}while(0)
-#define UNRECOGNIZED_OPTION(rval) \
+#define UNRECOGNIZED_OPTION() \
 	do{ \
 		fprintf(stderr, "Unrecognized command line option '%s'\n\n", argv[i]); \
 		free_cmd_args(&ret); \
-		usage(rval); \
+		usage(RETVAL_UNRECOGNIZED_OPTION); \
 	}while(0);
 
+struct arg_values init_arg_values(void){
+	return (struct arg_values){.next = NULL, .device = NULL, .delta = 0, .fade_duration = 0, .fade_steps = 20, .operation = 0};
+}
+
 //Convert command line arguments to flags
 struct arg_values process_cmd_args(int argc, char** argv){
-	struct arg_values ret = {0};
+	struct arg_values ret = init_arg_values();
 	struct arg_values* curr = &ret;
 
 	//Skip argv[0]
@@ -83,14 +90,21 @@ struct arg_values process_cmd_args(int argc, char** argv){
 			continue;
 
 		}else if(CHECK_OPTION(FADE, argv[i])){
-			CHECK_NEXT_ARG(-5);
+			CHECK_NEXT_ARG();
 			curr->fade_duration = strtol(argv[++i], NULL, 0);
 			continue;
 		}
 
+		else if(CHECK_OPTION(STEPS, argv[i])){
+			CHECK_NEXT_ARG();
+			curr->fade_steps = strtol(argv[++i], NULL, 0);
+			continue;
+		}
+
 		else if(CHECK_OPTION(DEVICE, argv[i])){
-			CHECK_NEXT_ARG(-5);
-			curr->next = calloc(1, sizeof(struct arg_values));
+			CHECK_NEXT_ARG();
+			curr->next = malloc(sizeof(struct arg_values));
+			*(curr->next) = init_arg_values();
 			curr = curr->next;
 			curr->device = argv[++i];
 			continue;
@@ -130,7 +144,7 @@ struct arg_values process_cmd_args(int argc, char** argv){
 		else if(argv[i][0] == '-'){
 			//If we get a '-' followed by not a number, it's not a known option
 			if(argv[i][1] < '0' || argv[i][1] > '9'){
-				UNRECOGNIZED_OPTION(RETVAL_UNRECOGNIZED_OPTION);
+				UNRECOGNIZED_OPTION();
 
 			//If we get a '-' followed by a number, it's a decrement request
 			}else{
@@ -144,7 +158,7 @@ struct arg_values process_cmd_args(int argc, char** argv){
 				if(argv[i][j] == '\0')
 					break;
 				if(argv[i][j] < '0' || argv[i][j] > '9')
-					UNRECOGNIZED_OPTION(RETVAL_UNRECOGNIZED_OPTION);
+					UNRECOGNIZED_OPTION();
 			}
 			curr->operation = OP_SET;
 			curr->delta = atof(argv[i]);

src/rexbacklight.c

@@ -15,11 +15,14 @@
 	You should have received a copy of the GNU General Public License
 	along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
+#define _DEFAULT_SOURCE
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <dirent.h>
+#include <sys/time.h>
 
 #include "common.h"
 #include "cmd.h"
@@ -116,16 +119,53 @@ float get_brightness(const char* file){
 	return atof(buff);
 }
 
+//update brightness incrementally over requested millisecond time interval
+void fade_out(int iv, int fv, int ms_duration, int steps){
+	FILE* fd;
+	struct timeval start, end;
+	double tdelta = 0;        //amount of time that has passed
+	float value = iv;        //current value to write to file
+	int step_delta = ms_duration / steps;
+	int step_inc = step_delta;
+	float brdelta = (float)(fv - iv) / steps; //amount brightness needs to change overall
+
+	while(ms_duration > tdelta){
+		//write
+		gettimeofday(&start, NULL);
+		fd = fopen(backlight_file, "w+");
+		if(!fd){
+			io_error_2(IO_ERROR_OPEN, IO_ERROR_FILE, backlight_dir, backlight_file);
+			return;
+		}
+		fprintf(fd, "%d", (int)value);
+		fclose(fd);
+		gettimeofday(&end, NULL);
+
+		//calc time delta
+		tdelta += (((end.tv_sec * 1000.0) + (end.tv_usec / 1000.0)) - ((start.tv_sec * 1000.0) + (start.tv_usec / 1000.0)));
+
+		//calc next value to write
+		value += brdelta;
+
+		//waste excess time until next step
+		if(step_delta > tdelta){
+			usleep((step_delta - tdelta) * 1000);
+			tdelta = step_delta;
+		}
+		//calc end of next step
+		step_delta += step_inc;
+	}
+	fd = fopen(backlight_file, "w+");
+	fprintf(fd, "%d", fv);
+
+	fclose(fd);
+}
+
 //Write value to backlight files
 void do_assignment(struct arg_values* arg){
-	int out = process_op(arg, 0, get_brightness(backlight_file), get_brightness(max_backlight_file));
-	FILE* bright = fopen(backlight_file, "w+");
-	if(!bright){
-		io_error_2(IO_ERROR_OPEN, IO_ERROR_FILE, backlight_dir, backlight_file);
-		return;
-	}
-	fprintf(bright, "%d", out);
-	fclose(bright);
+	int start = get_brightness(backlight_file);
+	int out = process_op(arg, 0, start, get_brightness(max_backlight_file));
+	fade_out(start, out, arg->fade_duration, arg->fade_steps);
 }
 
 //Run get operation