by bkoc

Convert UIImage to ASCII art

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Example gif image

As seen on Cmd.fm iOS App


Cmd.fm screenshot 1 Cmd.fm screenshot 2


BKAsciiImage is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod "BKAsciiImage"


Using BKAsciiConverter class

Import BKAsciiConverter header file


Create a BKAsciiConverter instance

BKAsciiConverter *converter = [BKAsciiConverter new];

Convert synchronously

UIImage *inputImage = [UIImage imageNamed:@"anImage"];
UIImage *asciiImage = [converter convertImage:inputImage];

Convert in the background providing a completion block. Completion block will be called on the main thread.

[converter convertImage:self.inputImage completionHandler:^(UIImage *asciiImage) {
    // do whatever you want with the resulting asciiImage

Convert to NSString ```objective-c NSLog(@"%@",[converter convertToString:self.inputImage]);

// asynchronous [converter convertToString:self.inputImage completionHandler:^(NSString *asciiString) { NSLog(@"%@",asciiString); }]; ```

Converter options

converter.backgroundColor = [UIColor whiteColor]; // default: Clear color. Image background is transparent
converter.grayscale = YES; // default: NO
converter.font = [UIFont fontWithName:@"Monaco" size:13.0]; // default: System font of size 10
converter.reversedLuminance = NO; // Reverses the luminance mapping. Reversing gives better results on a dark bg. default: YES
converter.columns = 50; // By default columns is derived by the font size if not set explicitly

Using UIImage category

Import header file


Use the provided category methods

UIImage *inputImage = [UIImage imageNamed:@"anImage"];
[inputImage bk_asciiImageCompletionHandler:^(UIImage *asciiImage) {


[inputImage bk_asciiStringCompletionHandler:^(NSString *asciiString) {


[inputImage bk_asciiImageWithFont: [UIFont fontWithName:@"Monaco" size:13.0] bgColor: [UIColor redColor]; columns: 30 reversed: YES grayscale: NO completionHandler: ^(NSString *asciiString) { // do whatever you want with the resulting asciiImage }];

Advanced usage

By default luminance values are mapped to strings using

NSDictionary *dictionary = @{  @1.0: @" ",
                               @0.9 :@",",
                               @0.8 :@"-",
                               @0.7 :@"+",
                               @0.5 :@"=",
                               @0.3 :@"%",
                               @0.1 :@"X",
                               @0.0 :@"@"

You can instantiate a converter with your own mapping dictionary

NSDictionary *dictionary = @{  @1.0: @" ",
                               @0.7 :@"a",
                               @0.6 :@"c",
                               @0.5 :@"e",
                               @0.3 :@"g",
                               @0.1 :@" ",
                               @0.0 :@" "

BKAsciiConverter *converter = [[BKAsciiConverter alloc] initWithDictionary:dictionary]; UIImage *inputImage = [UIImage imageNamed:@"anImage"]; UIImage *asciiImage = [converter convertImage:inputImage];

Mapping example screenshot


Barış Koç, https://github.com/bkoc


BKAsciiImage is available under the MIT license. See the LICENSE file for more info.

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