This is an implementation of the Moore Neighborhood algorithm used to trace the contours of a given image and output a JSON (or plist) file of the resulting pixel coordinates. If an image is made up of more than one body, the coordinate data for each body will be stored in a separate array. Coordinate data is of the form @"{x,y}" and can be parsed from an iOS application using CGPointFromString.
Example JSON data for an image made up of two rectangular bodies:
[["{0,0}","{0,1}","{1,1}","{1,0}"],["{3,2}","{5,2}","{5,3}","{3,3}"]].
In order to use the program, follow these steps:
debug_constants.h
// select highest alpha value considered "clear" (0 thru 255)
#define ALPHA_THRESHOLD 100
// select image format
#define IMAGE_FORMAT @"png"
// select @"json" or @"plist"
#define FILE_TYPE_TO_RETURN @"json"
// select destination for your data
#define DESTINATION_FOLDER @"/Users/markkim/Desktop/test_tile_data/"
// select images (note: add images to project before compiling)
#define SPRITE_NAMES @[@"cloud", @"alien"]
Sample images taken from http://kenney.nl/