Split an image

gistfile1.m

///分割图片
static inline NSArray* WKFlip_make_hsplit_images_for_image(UIImage* image){
    CGSize halfSize=CGSizeMake(image.size.width, image.size.height/2);
    UIGraphicsBeginImageContext(halfSize);
    CGContextRef context=UIGraphicsGetCurrentContext();
    CGContextSaveGState(context);
    // Flip the coordinate system
    CGContextSetTextMatrix(context, CGAffineTransformIdentity); // 2-1
    CGContextTranslateCTM(context, 0, halfSize.height); // 3-1
    CGContextScaleCTM(context, 1.0, -1.0); // 4-1
    CGImageRef imageRef=image.CGImage;
    CGContextDrawImage(context, CGRectMake(0, -1*halfSize.height,
                                           image.size.width,
                                           image.size.height),
                       imageRef);
    UIImage* imageFirst=UIGraphicsGetImageFromCurrentImageContext();
    
    CGContextClearRect(context, CGRectMake(0, 0, image.size.width , image.size.height));
    CGContextDrawImage(context, CGRectMake(0,0,
                                           image.size.width,
                                           image.size.height),
                       imageRef);
    UIImage* imageSecond=UIGraphicsGetImageFromCurrentImageContext();
    CGContextRestoreGState(context);
    UIGraphicsEndImageContext();
    //WLog_Float(@"hSplitImageToArray duration", CFAbsoluteTimeGetCurrent()-startTime);
    return @[imageFirst,imageSecond,];
}