Make sure we never output numbers in scientific notation

Converting NSNumber to a string raises the possibility of outputing a
number like 2.2e-8, as it essentially uses the %g format specifier.
This then cannot be parsed.

Since there is no built-in specifier for outputing floats with variable
precision (ie: removing any trailing zeros), I cooked up a function to
do just that.

Currently set the maximum precision at 4dp (our normal grid layout only
makes use of 2dp).

3 files changed, 33 insertions, 3 deletions

diff --git a/tikzit/src/common/Graph.m b/tikzit/src/common/Graph.m
index 258ece4..2d07ccc 100644
--- a/tikzit/src/common/Graph.m
+++ b/tikzit/src/common/Graph.m
@@ -720,8 +720,8 @@
 		[code appendFormat:@"\t\t\\node %@ (%d) at (%@, %@) {%@};\n",
 			[[n data] tikzList],
 			i,
-			[NSNumber numberWithFloat:[n point].x],
-			[NSNumber numberWithFloat:[n point].y],
+			formatFloat([n point].x, 4),
+			formatFloat([n point].y, 4),
 			[n label]
 		];
         i++;
diff --git a/tikzit/src/common/util.h b/tikzit/src/common/util.h
index f527820..b34f25d 100644
--- a/tikzit/src/common/util.h
+++ b/tikzit/src/common/util.h
@@ -191,4 +191,11 @@ NSString *alphaHex(unsigned short sh);
 
 const char *find_start_of_nth_line (const char * string, int line);
 
-// vi:ft=objc:noet:ts=4:sts=4:sw=4
+/*!
+ @brief      Formats a CGFloat as a string, removing trailing zeros
+ @detail     Unlike formatting an NSNumber, or using %g, it will never
+             produce scientific notation (like "2.00e2").  Unlike %f,
+             it will not include unnecessary trailing zeros.
+ */
+NSString *formatFloat(CGFloat f, int maxdps);
+
diff --git a/tikzit/src/common/util.m b/tikzit/src/common/util.m
index aa21a67..e9b8899 100644
--- a/tikzit/src/common/util.m
+++ b/tikzit/src/common/util.m
@@ -376,5 +376,28 @@ const char *find_start_of_nth_line (const char * string, int line) {
 	return lineStart;
 }
 
+NSString *formatFloat(CGFloat f, int maxdps) {
+	NSMutableString *result = [NSMutableString
+		stringWithFormat:@"%.*f", maxdps, f];
+	// delete trailing zeros
+	NSUInteger lastPos = [result length] - 1;
+	NSUInteger firstDigit = ([result characterAtIndex:0] == '-') ? 1 : 0;
+	while (lastPos > firstDigit) {
+		if ([result characterAtIndex:lastPos] == '0') {
+			[result deleteCharactersInRange:NSMakeRange(lastPos, 1)];
+			lastPos -= 1;
+		} else {
+			break;
+		}
+	}
+	if ([result characterAtIndex:lastPos] == '.') {
+		[result deleteCharactersInRange:NSMakeRange(lastPos, 1)];
+		lastPos -= 1;
+	}
+	if ([@"-0" isEqualToString:result])
+		return @"0";
+	else
+		return result;
+}
 
 // vi:ft=objc:noet:ts=4:sts=4:sw=4