diff --git a/src/controller.rs b/src/controller.rs
index ae606e31..0249035b 100644
--- a/src/controller.rs
+++ b/src/controller.rs
@@ -1,5 +1,4 @@
 use std::io::{self, Write};
-use std::mem::swap;
 
 use app::Config;
 use assets::HighlightingAssets;
@@ -7,7 +6,6 @@ use errors::*;
 use inputfile::{InputFile, InputFileReader};
 use line_range::{LineRanges, RangeCheckResult};
 use output::OutputType;
-use preprocessor::replace_nonprintable;
 use printer::{InteractivePrinter, Printer, SimplePrinter};
 
 pub struct Controller<'a> {
@@ -66,14 +64,7 @@ impl<'b> Controller<'b> {
         input_file: InputFile<'a>,
     ) -> Result<()> {
         printer.print_header(writer, input_file)?;
-        self.print_file_ranges(
-            printer,
-            writer,
-            reader,
-            &self.config.line_ranges,
-            self.config.show_nonprintable,
-            self.config.tab_width,
-        )?;
+        self.print_file_ranges(printer, writer, reader, &self.config.line_ranges)?;
         printer.print_footer(writer)?;
 
         Ok(())
@@ -85,20 +76,11 @@ impl<'b> Controller<'b> {
         writer: &mut Write,
         mut reader: InputFileReader,
         line_ranges: &LineRanges,
-        show_nonprintable: bool,
-        tab_width: usize,
     ) -> Result<()> {
         let mut line_buffer = Vec::new();
-        let mut line_buffer_processed = Vec::new();
-
         let mut line_number: usize = 1;
 
         while reader.read_line(&mut line_buffer)? {
-            if show_nonprintable {
-                replace_nonprintable(&mut line_buffer, &mut line_buffer_processed, tab_width);
-                swap(&mut line_buffer, &mut line_buffer_processed);
-            }
-
             match line_ranges.check(line_number) {
                 RangeCheckResult::OutsideRange => {
                     // Call the printer in case we need to call the syntax highlighter
diff --git a/src/preprocessor.rs b/src/preprocessor.rs
index ec43febe..f3e2f4d1 100644
--- a/src/preprocessor.rs
+++ b/src/preprocessor.rs
@@ -33,39 +33,41 @@ pub fn expand_tabs(line: &str, width: usize, cursor: &mut usize) -> String {
     buffer
 }
 
-pub fn replace_nonprintable(input: &mut Vec<u8>, output: &mut Vec<u8>, tab_width: usize) {
-    output.clear();
+pub fn replace_nonprintable(input: &str, tab_width: usize) -> String {
+    let mut output = String::new();
 
     let tab_width = if tab_width == 0 { 4 } else { tab_width };
 
-    for chr in input {
-        match *chr {
+    for chr in input.chars() {
+        match chr {
             // space
-            b' ' => output.extend_from_slice("•".as_bytes()),
+            ' ' => output.push('•'),
             // tab
-            b'\t' => {
+            '\t' => {
                 if tab_width == 1 {
-                    output.extend_from_slice("↹".as_bytes());
+                    output.push('↹');
                 } else {
-                    output.extend_from_slice("├".as_bytes());
-                    output.extend_from_slice("─".repeat(tab_width - 2).as_bytes());
-                    output.extend_from_slice("┤".as_bytes());
+                    output.push('├');
+                    output.push_str(&"─".repeat(tab_width - 2));
+                    output.push('┤');
                 }
             }
             // line feed
-            0x0A => output.extend_from_slice("␊".as_bytes()),
+            '\x0A' => output.push('␊'),
             // carriage return
-            0x0D => output.extend_from_slice("␍".as_bytes()),
+            '\x0D' => output.push('␍'),
             // null
-            0x00 => output.extend_from_slice("␀".as_bytes()),
+            '\x00' => output.push('␀'),
             // bell
-            0x07 => output.extend_from_slice("␇".as_bytes()),
+            '\x07' => output.push('␇'),
             // backspace
-            0x08 => output.extend_from_slice("␈".as_bytes()),
+            '\x08' => output.push('␈'),
             // escape
-            0x1B => output.extend_from_slice("␛".as_bytes()),
+            '\x1B' => output.push('␛'),
             // anything else
-            _ => output.push(*chr),
+            _ => output.push(chr),
         }
     }
+
+    output
 }
diff --git a/src/printer.rs b/src/printer.rs
index 593853cf..5346d4e8 100644
--- a/src/printer.rs
+++ b/src/printer.rs
@@ -22,7 +22,7 @@ use diff::get_git_diff;
 use diff::LineChanges;
 use errors::*;
 use inputfile::{InputFile, InputFileReader};
-use preprocessor::expand_tabs;
+use preprocessor::{expand_tabs, replace_nonprintable};
 use style::OutputWrap;
 use terminal::{as_terminal_escaped, to_ansi_color};
 
@@ -251,7 +251,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
         line_number: usize,
         line_buffer: &[u8],
     ) -> Result<()> {
-        let line = match self.content_type {
+        let mut line = match self.content_type {
             ContentType::BINARY => {
                 return Ok(());
             }
@@ -263,6 +263,11 @@ impl<'a> Printer for InteractivePrinter<'a> {
                 .unwrap_or("Invalid UTF-16BE".into()),
             _ => String::from_utf8_lossy(&line_buffer).to_string(),
         };
+
+        if self.config.show_nonprintable {
+            line = replace_nonprintable(&mut line, self.config.tab_width);
+        }
+
         let regions = {
             let highlighter = match self.highlighter {
                 Some(ref mut highlighter) => highlighter,