Merge pull request #7 from carbocation/master

Add interpolation choice flag

main.go

@@ -37,6 +37,8 @@ const ANSI_FG_TRANSPARENT_COLOR = "\x1b[0m "
 const ANSI_FG_RGB_COLOR = "\x1b[38;2;%d;%d;%dm▄"
 const ANSI_RESET = "\x1b[0m"
 
+var InterpolationType = imaging.Lanczos
+
 func read(input string) []byte {
 	var err error
 	var buf []byte
@@ -159,7 +161,7 @@ func scale(frames []image.Image) []image.Image {
 
 	for i, f := range frames {
 		go func(i int, f image.Image) {
-			c <- &data{i, imaging.Fit(f, w, h, imaging.Lanczos)}
+			c <- &data{i, imaging.Fit(f, w, h, InterpolationType)}
 		}(i, f)
 	}
 
@@ -266,13 +268,21 @@ func print(frames [][]string) {
 }
 
 func main() {
-	flag.Parse()
+	interpolation := flag.String("interpolation", "lanczos", "Interpolation method. Options: lanczos, nearest")
+	ParseFlags()
 
 	input := ""
 	if len(flag.Args()) > 0 {
 		args := flag.Args()
 		input = args[0]
 	}
 
+	switch *interpolation {
+	case "nearest":
+		InterpolationType = imaging.NearestNeighbor
+	default:
+		InterpolationType = imaging.Lanczos
+	}
+
 	print(escape(scale(decode(read(input)))))
 }

positional_flagset.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"flag"
+	"os"
+)
+
+// Via https://stackoverflow.com/a/74146375/199475
+
+// ParseFlags parses the command line args, allowing flags to be
+// specified after positional args.
+func ParseFlags() error {
+	return ParseFlagSet(flag.CommandLine, os.Args[1:])
+}
+
+// ParseFlagSet works like flagset.Parse(), except positional arguments are not
+// required to come after flag arguments.
+func ParseFlagSet(flagset *flag.FlagSet, args []string) error {
+	var positionalArgs []string
+	for {
+		if err := flagset.Parse(args); err != nil {
+			return err
+		}
+		// Consume all the flags that were parsed as flags.
+		args = args[len(args)-flagset.NArg():]
+		if len(args) == 0 {
+			break
+		}
+		// There's at least one flag remaining and it must be a positional arg since
+		// we consumed all args that were parsed as flags. Consume just the first
+		// one, and retry parsing, since subsequent args may be flags.
+		positionalArgs = append(positionalArgs, args[0])
+		args = args[1:]
+	}
+	// Parse just the positional args so that flagset.Args()/flagset.NArgs()
+	// return the expected value.
+	// Note: This should never return an error.
+	return flagset.Parse(positionalArgs)
+}