#import "UIImage+Editor.h"

CGFloat degreesToRadians (CGFloat degrees) {

return (degrees / 180.0) * M_PI;

}

CGFloat radiansToDegrees (CGFloat radians) {

return (radians / M_PI) * 180.0;

}

@implementation UIImage (Editor)

- (UIImage *) resizedToSize: (CGSize) size {

return [self resizedImage: size interpolationQuality: kCGInterpolationHigh];

}

- (UIImage *) resizedByRatio: (CGFloat) ratio {

CGSize newSize = CGSizeMake (self.size.width * ratio, self.size.height * ratio);

return [self resizedToSize: newSize];

}

- (UIImage *) croppedToRect: (CGRect) rect {

return [self croppedImage: rect];

}

- (UIImage *) withBorderRadius: (CGFloat) radius {

return [self roundedCornerImage: round (radius) borderSize: 0];

}

- (UIImage *) addText: (NSString *) str atPoint: (CGPoint) point withFont: (UIFont *) font ofColor: (UIColor *) color {

int w = self.size.width;

int h = self.size.height;

// create empty bitmap context

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB ();

CGContextRef ctx = CGBitmapContextCreate (NULL, w, h, 8, w * 4, colorSpace, kCGImageAlphaPremultipliedFirst);

CGContextSetInterpolationQuality (ctx, kCGInterpolationHigh);

CGAffineTransform transform = [self transformForOrientation: self.size];

CGContextConcatCTM (ctx, transform);

CGContextSetTextMatrix (ctx, CGAffineTransformInvert (transform));

BOOL transposed;

switch (self.imageOrientation) {

case UIImageOrientationLeft:

case UIImageOrientationLeftMirrored:

case UIImageOrientationRight:

case UIImageOrientationRightMirrored:

transposed = YES;

break;

default:

transposed = NO;

break;

}

// draw the image and the text on the bitmap context

CGContextDrawImage (ctx, transposed ? CGRectMake (0, 0, h, w) : CGRectMake (0, 0, w, h), [self CGImage]);

char *text = (char *)[str cStringUsingEncoding: NSASCIIStringEncoding];

CGContextSetTextDrawingMode (ctx, kCGTextFill);

CGFloat *comp = CGColorGetComponents ([color CGColor]);

CGContextSetRGBFillColor (ctx, comp[0], comp[1], comp[2], comp[3]);

CGContextSelectFont (ctx, [[font fontName] UTF8String], [font pointSize], kCGEncodingMacRoman);

CGContextShowTextAtPoint (ctx, point.x, h - point.y, text, strlen (text));

// get the image as a UIImage and clean up

CGImageRef imageMasked = CGBitmapContextCreateImage (ctx);

UIImage *img = [UIImage imageWithCGImage: imageMasked];

CGContextRelease (ctx);

CGImageRelease (imageMasked);

CGColorSpaceRelease (colorSpace);

return img;

}

- (UIImage *) grayscaled {

// ARGB byte index constants (within a pixel represented by 4 bytes)

const uint8_t ALPHA = 0;

const uint8_t BLUE = 1;

const uint8_t GREEN = 2;

const uint8_t RED = 3;

// create an empty ARGB image

CGSize size = self.size;

int width = size.width;

int height = size.height;

uint32_t *pixels = (uint32_t *) malloc (width * height * sizeof (uint32_t));

// memset all pixels to (0, 0, 0, 0) to preserve transparency if existed

memset (pixels, 0, width * height * sizeof (uint32_t));

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB ();

CGContextRef context = CGBitmapContextCreate (pixels, width, height, 8, width * sizeof (uint32_t), colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedLast);

// draw the image on the bitmap context

CGContextDrawImage (context, CGRectMake (0, 0, width, height), [self CGImage]);

for (int y = 0; y < height; y++) {

for (int x = 0; x < width; x++) {

uint8_t *rgbaPixel = (uint8_t *) &pixels[y * width + x];

// convert to grayscale using recommended weighting method: http://en.wikipedia.org/wiki/Grayscale#Converting_color_to_grayscale

uint32_t gray = 0.3 * rgbaPixel[RED] + 0.59 * rgbaPixel[GREEN] + 0.11 * rgbaPixel[BLUE];

rgbaPixel[RED] = gray;

rgbaPixel[GREEN] = gray;

rgbaPixel[BLUE] = gray;

}

}

// get image and clean up

CGImageRef image = CGBitmapContextCreateImage (context);

CGContextRelease (context);

CGColorSpaceRelease (colorSpace);

free (pixels);

UIImage *resultUIImage = [UIImage imageWithCGImage: image];

CGImageRelease (image);

return resultUIImage;

}

- (UIImage *) withAlpha: (CGFloat) alpha {

int w = self.size.width;

int h = self.size.height;

// create empty ARGB image

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB ();

CGContextRef ctx = CGBitmapContextCreate (NULL, w, h, 8, w * 4, colorSpace, kCGImageAlphaPremultipliedFirst);

// leave the image in its original quality

CGContextSetInterpolationQuality (ctx, kCGInterpolationHigh);

CGAffineTransform transform = [self transformForOrientation: self.size];

CGContextConcatCTM (ctx, transform);

// actually adjust transparency factor

CGContextSetAlpha (ctx, alpha);

BOOL transposed;

// adjust stretch ratio according to orientation

switch (self.imageOrientation) {

case UIImageOrientationLeft:

case UIImageOrientationLeftMirrored:

case UIImageOrientationRight:

case UIImageOrientationRightMirrored:

transposed = YES;

break;

default:

transposed = NO;

break;

}

// draw the modified image on the bitmap context

CGContextDrawImage (ctx, transposed ? CGRectMake (0, 0, h, w) : CGRectMake (0, 0, w, h), [self CGImage]);

CGImageRef imageMasked = CGBitmapContextCreateImage (ctx);

// get it as a UIImage from the context

UIImage *img = [UIImage imageWithCGImage: imageMasked];

// clean up

CGContextRelease (ctx);

CGImageRelease (imageMasked);

CGColorSpaceRelease (colorSpace);

return img;

}

- (UIImage *) rotatedByDegrees: (CGFloat) degrees {

// calculate the size of the rotated view's containing box for our drawing space

UIView *rotatedViewBox = [[UIView alloc] initWithFrame: CGRectMake (0, 0, self.size.width, self.size.height)];

CGAffineTransform t = CGAffineTransformMakeRotation (degreesToRadians (degrees));

rotatedViewBox.transform = t;

CGSize rotatedSize = rotatedViewBox.frame.size;

[rotatedViewBox release];

// Create the bitmap context

UIGraphicsBeginImageContext (rotatedSize);

CGContextRef bitmap = UIGraphicsGetCurrentContext ();

// Move the origin to the middle of the image so we will rotate and scale around the center.

CGContextTranslateCTM (bitmap, rotatedSize.width / 2, rotatedSize.height / 2);

// Rotate the image context

CGContextRotateCTM (bitmap, degreesToRadians (degrees));

// Now, draw the rotated/scaled image into the context

CGContextScaleCTM (bitmap, 1.0, -1.0);

CGContextDrawImage (bitmap, CGRectMake (-self.size.width / 2, -self.size.height / 2, self.size.width, self.size.height), [self CGImage]);

UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return newImage;

}