main.m

//
//  main.m
//  mudaImagens
//
//  Created by Paulo Cesar on 09/02/16.
//  Copyright © 2016 Paulo Cesar. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <AppKit/AppKit.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // insert code here...
        NSString* dirPath = [NSString stringWithCString:argv[1] encoding:NSUTF8StringEncoding];
        NSFileManager* manager = [NSFileManager defaultManager];
        
        NSError* error;
        NSArray* files = [manager contentsOfDirectoryAtPath:dirPath error:&error];
        
        if (files) {
            for (NSString* fileName in files) {
                if ([fileName hasSuffix:@".png"]) {
                    NSString* imagePath = [NSString stringWithFormat:@"%@/%@", dirPath, fileName];
                    NSImage* image = [[NSImage alloc] initWithContentsOfFile:imagePath];
                    
                    if (image.representations && image.representations.count > 0) {
                        long lastSquare = 0, curSquare;
                        NSImageRep *imageRep;
                        for (imageRep in image.representations) {
                            curSquare = imageRep.pixelsWide * imageRep.pixelsHigh;
                            if (curSquare > lastSquare) {
                                image.size = NSMakeSize(imageRep.pixelsWide, imageRep.pixelsHigh);
                                lastSquare = curSquare;
                            }
                        }
                        
                        if (image.size.width != image.size.height) {
                            float maxSize = MAX(image.size.width, image.size.height);
                            
                            NSSize finalSize;
                            finalSize.width = maxSize;
                            finalSize.height = maxSize;
                            
                            NSBitmapImageRep *rep = [[NSBitmapImageRep alloc]
                                                     initWithBitmapDataPlanes:NULL
                                                     pixelsWide:maxSize
                                                     pixelsHigh:maxSize
                                                     bitsPerSample:16
                                                     samplesPerPixel:4
                                                     hasAlpha:YES
                                                     isPlanar:NO
                                                     colorSpaceName:NSCalibratedRGBColorSpace
                                                     bytesPerRow:0
                                                     bitsPerPixel:0];
                            
                            [rep setSize:finalSize];
                            
                            NSRect rect = NSMakeRect((maxSize-image.size.width)/2,
                                                     (maxSize-image.size.height)/2,
                                                     image.size.width,
                                                     image.size.height);
                            
                            [NSGraphicsContext saveGraphicsState];
                            [NSGraphicsContext setCurrentContext:[NSGraphicsContext     graphicsContextWithBitmapImageRep:rep]];
                            [image drawInRect:rect  fromRect:NSZeroRect operation:NSCompositeCopy fraction:1.0];
                            [NSGraphicsContext restoreGraphicsState];
                            
                            NSData *data = [rep representationUsingType:NSPNGFileType properties:nil];
                            
                            [data writeToFile:imagePath atomically:YES];
                            
                            NSLog(@"mudou imagem: %@", fileName);
                        }
                    }
                }
            }
        }
    }
    return 0;
}