WeChat1/Pods/UIImage+SKYExtension/UIImageCategory/UIImage+SKYExtension.m
//
//  UIImage+SKYExtension.m
//  MyCategory
//
//  Created by Topsky on 16/9/26.
//  Copyright © 2016年 Topsky. All rights reserved.
//

#import "UIImage+SKYExtension.h"
#import <ImageIO/ImageIO.h>

//由角度转换弧度
#define kDegreesToRadian(x)      (M_PI * (x) / 180.0)
//由弧度转换角度
#define kRadianToDegrees(radian) (radian * 180.0) / (M_PI)

@implementation UIImage (SKYExtension)

//根据颜色生成纯色图片
+ (UIImage *)imageWithColor:(UIColor *)color {
    CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSetFillColorWithColor(context, [color CGColor]);
    CGContextFillRect(context, rect);

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return image;
}

//UIView转化为UIImage
+ (UIImage *)imageFromView:(UIView *)view {
    CGFloat scale = [UIScreen mainScreen].scale;
    UIGraphicsBeginImageContextWithOptions(view.frame.size, NO, scale);
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return image;
}

//将两个图片生成一张图片
+ (UIImage *)mergeImage:(UIImage *)firstImage withImage:(UIImage *)secondImage {
    CGImageRef firstImageRef = firstImage.CGImage;
    CGFloat firstWidth = CGImageGetWidth(firstImageRef);
    CGFloat firstHeight = CGImageGetHeight(firstImageRef);
    CGImageRef secondImageRef = secondImage.CGImage;
    CGFloat secondWidth = CGImageGetWidth(secondImageRef);
    CGFloat secondHeight = CGImageGetHeight(secondImageRef);
    CGSize mergedSize = CGSizeMake(MAX(firstWidth, secondWidth), MAX(firstHeight, secondHeight));
    UIGraphicsBeginImageContext(mergedSize);
    [firstImage drawInRect:CGRectMake(0, 0, firstWidth, firstHeight)];
    [secondImage drawInRect:CGRectMake(0, 0, secondWidth, secondHeight)];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

//改变图片的颜色
- (UIImage *)imageWithTintColor:(UIColor *)tintColor {
    UIGraphicsBeginImageContextWithOptions(self.size, NO, 0.0f);
    [tintColor setFill];
    CGRect bounds = CGRectMake(0, 0, self.size.width, self.size.height);
    UIRectFill(bounds);

    [self drawInRect:bounds blendMode:kCGBlendModeDestinationIn alpha:1.0f];

    UIImage *tintedImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return tintedImage;
}

//取图片某一像素的颜色
- (UIColor *)colorAtPixel:(CGPoint)point {
    if (!CGRectContainsPoint(CGRectMake(0.0f, 0.0f, self.size.width, self.size.height), point)) {
        return nil;
    }

    NSInteger pointX = trunc(point.x);
    NSInteger pointY = trunc(point.y);
    CGImageRef cgImage = self.CGImage;
    NSUInteger width = self.size.width;
    NSUInteger height = self.size.height;
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    int bytesPerPixel = 4;
    int bytesPerRow = bytesPerPixel * 1;
    NSUInteger bitsPerComponent = 8;
    unsigned char pixelData[4] = {0, 0, 0, 0};
    CGContextRef context = CGBitmapContextCreate(pixelData,
        1,
        1,
        bitsPerComponent,
        bytesPerRow,
        colorSpace,
        kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
    CGColorSpaceRelease(colorSpace);
    CGContextSetBlendMode(context, kCGBlendModeCopy);

    CGContextTranslateCTM(context, -pointX, pointY - (CGFloat) height);
    CGContextDrawImage(context, CGRectMake(0.0f, 0.0f, (CGFloat) width, (CGFloat) height), cgImage);
    CGContextRelease(context);

    CGFloat red = (CGFloat) pixelData[0] / 255.0f;
    CGFloat green = (CGFloat) pixelData[1] / 255.0f;
    CGFloat blue = (CGFloat) pixelData[2] / 255.0f;
    CGFloat alpha = (CGFloat) pixelData[3] / 255.0f;
    return [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
}

//获得灰度图
- (UIImage *)convertToGrayImage {
    int width = self.size.width;
    int height = self.size.height;

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();
    CGContextRef context = CGBitmapContextCreate(nil, width, height, 8, 0, colorSpace, kCGImageAlphaNone);
    CGColorSpaceRelease(colorSpace);

    if (context == NULL) {
        return nil;
    }

    CGContextDrawImage(context, CGRectMake(0, 0, width, height), self.CGImage);
    CGImageRef contextRef = CGBitmapContextCreateImage(context);
    UIImage *grayImage = [UIImage imageWithCGImage:contextRef];
    CGContextRelease(context);
    CGImageRelease(contextRef);

    return grayImage;
}

#pragma mark - rotate

/** 纠正图片的方向 */
- (UIImage *)fixOrientation {
    if (self.imageOrientation == UIImageOrientationUp) return self;

    // We need to calculate the proper transformation to make the image upright.
    // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
    CGAffineTransform transform = CGAffineTransformIdentity;

    switch (self.imageOrientation) {
        case UIImageOrientationDown:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, self.size.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;

        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;

        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, 0, self.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        case UIImageOrientationUp:
        case UIImageOrientationUpMirrored:
            break;
    }

    switch (self.imageOrientation) {
        case UIImageOrientationUpMirrored:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;

        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
        case UIImageOrientationUp:
        case UIImageOrientationDown:
        case UIImageOrientationLeft:
        case UIImageOrientationRight:
            break;
    }

    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    CGContextRef ctx = CGBitmapContextCreate(NULL, self.size.width, self.size.height,
        CGImageGetBitsPerComponent(self.CGImage), 0,
        CGImageGetColorSpace(self.CGImage),
        CGImageGetBitmapInfo(self.CGImage));
    CGContextConcatCTM(ctx, transform);

    switch (self.imageOrientation) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            CGContextDrawImage(ctx, CGRectMake(0, 0, self.size.height, self.size.width), self.CGImage);
            break;

        default:
            CGContextDrawImage(ctx, CGRectMake(0, 0, self.size.width, self.size.height), self.CGImage);
            break;
    }

    CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
    UIImage *img = [UIImage imageWithCGImage:cgimg];
    CGContextRelease(ctx);
    CGImageRelease(cgimg);

    return img;
}

/** 按给定的方向旋转图片 */
- (UIImage *)rotate:(UIImageOrientation)orient {
    CGRect bnds = CGRectZero;
    UIImage *copy = nil;
    CGContextRef ctxt = nil;
    CGImageRef imag = self.CGImage;
    CGRect rect = CGRectZero;
    CGAffineTransform tran = CGAffineTransformIdentity;

    rect.size.width = CGImageGetWidth(imag);
    rect.size.height = CGImageGetHeight(imag);

    bnds = rect;

    switch (orient) {
        case UIImageOrientationUp:
            return self;

        case UIImageOrientationUpMirrored:
            tran = CGAffineTransformMakeTranslation(rect.size.width, 0.0);
            tran = CGAffineTransformScale(tran, -1.0, 1.0);
            break;

        case UIImageOrientationDown:
            tran = CGAffineTransformMakeTranslation(rect.size.width,
                rect.size.height);
            tran = CGAffineTransformRotate(tran, M_PI);
            break;

        case UIImageOrientationDownMirrored:
            tran = CGAffineTransformMakeTranslation(0.0, rect.size.height);
            tran = CGAffineTransformScale(tran, 1.0, -1.0);
            break;

        case UIImageOrientationLeft:
            bnds = swapWidthAndHeight(bnds);
            tran = CGAffineTransformMakeTranslation(0.0, rect.size.width);
            tran = CGAffineTransformRotate(tran, 3.0 * M_PI / 2.0);
            break;

        case UIImageOrientationLeftMirrored:
            bnds = swapWidthAndHeight(bnds);
            tran = CGAffineTransformMakeTranslation(rect.size.height,
                rect.size.width);
            tran = CGAffineTransformScale(tran, -1.0, 1.0);
            tran = CGAffineTransformRotate(tran, 3.0 * M_PI / 2.0);
            break;

        case UIImageOrientationRight:
            bnds = swapWidthAndHeight(bnds);
            tran = CGAffineTransformMakeTranslation(rect.size.height, 0.0);
            tran = CGAffineTransformRotate(tran, M_PI / 2.0);
            break;

        case UIImageOrientationRightMirrored:
            bnds = swapWidthAndHeight(bnds);
            tran = CGAffineTransformMakeScale(-1.0, 1.0);
            tran = CGAffineTransformRotate(tran, M_PI / 2.0);
            break;

        default:
            return self;
    }

    UIGraphicsBeginImageContext(bnds.size);
    ctxt = UIGraphicsGetCurrentContext();

    switch (orient) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            CGContextScaleCTM(ctxt, -1.0, 1.0);
            CGContextTranslateCTM(ctxt, -rect.size.height, 0.0);
            break;

        default:
            CGContextScaleCTM(ctxt, 1.0, -1.0);
            CGContextTranslateCTM(ctxt, 0.0, -rect.size.height);
            break;
    }

    CGContextConcatCTM(ctxt, tran);
    CGContextDrawImage(UIGraphicsGetCurrentContext(), rect, imag);

    copy = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return copy;
}

/** 垂直翻转 */
- (UIImage *)flipVertical {
    return [self rotate:UIImageOrientationDownMirrored];
}

/** 水平翻转 */
- (UIImage *)flipHorizontal {
    return [self rotate:UIImageOrientationUpMirrored];
}

/** 将图片旋转弧度radians */
- (UIImage *)imageRotatedByRadians:(CGFloat)radians {
    // 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(radians);
    rotatedViewBox.transform = t;
    CGSize rotatedSize = rotatedViewBox.frame.size;

    // 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, radians);

    // 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;
}

/** 将图片旋转角度degrees */
- (UIImage *)imageRotatedByDegrees:(CGFloat)degrees {
    return [self imageRotatedByRadians:kDegreesToRadian(degrees)];
}

/** 交换宽和高 */
static CGRect swapWidthAndHeight(CGRect rect) {
    CGFloat swap = rect.size.width;

    rect.size.width = rect.size.height;
    rect.size.height = swap;

    return rect;
}

#pragma mark - gif

static int delayCentisecondsForImageAtIndex(CGImageSourceRef const source, size_t const i) {
    int delayCentiseconds = 1;
    CFDictionaryRef const properties = CGImageSourceCopyPropertiesAtIndex(source, i, NULL);
    if (properties) {
        CFDictionaryRef const gifProperties = CFDictionaryGetValue(properties, kCGImagePropertyGIFDictionary);
        if (gifProperties) {
            NSNumber *number = (__bridge id) CFDictionaryGetValue(gifProperties, kCGImagePropertyGIFUnclampedDelayTime);
            if (number == NULL || [number doubleValue] == 0) {
                number = (__bridge id) CFDictionaryGetValue(gifProperties, kCGImagePropertyGIFDelayTime);
            }
            if ([number doubleValue] > 0) {
                delayCentiseconds = (int) lrint([number doubleValue] * 100);
            }
        }
        CFRelease(properties);
    }
    return delayCentiseconds;
}

static void createImagesAndDelays(CGImageSourceRef source, size_t count, CGImageRef imagesOut[count], int delayCentisecondsOut[count]) {
    for (size_t i = 0; i < count; ++i) {
        imagesOut[i] = CGImageSourceCreateImageAtIndex(source, i, NULL);
        delayCentisecondsOut[i] = delayCentisecondsForImageAtIndex(source, i);
    }
}

static int sum(size_t const count, int const *const values) {
    int theSum = 0;
    for (size_t i = 0; i < count; ++i) {
        theSum += values[i];
    }
    return theSum;
}

static int pairGCD(int a, int b) {
    if (a < b) {
        return pairGCD(b, a);
    }

    while (YES) {
        int const r = a % b;
        if (r == 0) {
            return b;
        }
        a = b;
        b = r;
    }
}

static int vectorGCD(size_t const count, int const *const values) {
    int gcd = values[0];
    for (size_t i = 1; i < count; ++i) {
        gcd = pairGCD(values[i], gcd);
    }
    return gcd;
}

static NSArray *frameArray(size_t const count, CGImageRef const images[count], int const delayCentiseconds[count], int const totalDurationCentiseconds) {
    int const gcd = vectorGCD(count, delayCentiseconds);
    size_t const frameCount = totalDurationCentiseconds / gcd;
    UIImage *frames[frameCount];
    for (size_t i = 0, f = 0; i < count; ++i) {
        UIImage *const frame = [UIImage imageWithCGImage:images[i]];
        for (size_t j = delayCentiseconds[i] / gcd; j > 0; --j) {
            frames[f++] = frame;
        }
    }
    return [NSArray arrayWithObjects:frames count:frameCount];
}

static void releaseImages(size_t const count, CGImageRef const images[count]) {
    for (size_t i = 0; i < count; ++i) {
        CGImageRelease(images[i]);
    }
}

static UIImage *animatedImageWithAnimatedGIFImageSource(CGImageSourceRef const source) {
    size_t const count = CGImageSourceGetCount(source);
    CGImageRef images[count];
    int delayCentiseconds[count]; // in centiseconds
    createImagesAndDelays(source, count, images, delayCentiseconds);
    int const totalDurationCentiseconds = sum(count, delayCentiseconds);
    NSArray *const frames = frameArray(count, images, delayCentiseconds, totalDurationCentiseconds);
    UIImage *const animation = [UIImage animatedImageWithImages:frames duration:(NSTimeInterval) totalDurationCentiseconds / 100.0];
    releaseImages(count, images);
    return animation;
}

static UIImage *animatedImageWithAnimatedGIFReleasingImageSource(CGImageSourceRef CF_RELEASES_ARGUMENT source) {
    if (source) {
        UIImage *const image = animatedImageWithAnimatedGIFImageSource(source);
        CFRelease(source);
        return image;
    } else {
        return nil;
    }
}

+ (UIImage *)animatedImageWithAnimatedGIFData:(NSData *)data {
    return animatedImageWithAnimatedGIFReleasingImageSource(CGImageSourceCreateWithData((__bridge CFTypeRef) data, NULL));
}

+ (UIImage *)animatedImageWithAnimatedGIFURL:(NSURL *)url {
    return animatedImageWithAnimatedGIFReleasingImageSource(CGImageSourceCreateWithURL((__bridge CFTypeRef) url, NULL));
}

@end
