Operations on UIImage: operations on UIImage

Operations on UIImage: operations on UIImage

1. Generate a UIImage object with a specified width (oldImage is the original image object and newImage is the image object after the operation)

// Parameter 1: image size parameter 2: transparent (NO difference between YES and NO) parameter 3: Zoom (1 indicates NO scaling)

(1) uigraphicsbeginimagecontextwitexceptions (CGSize size, BOOL opaque, CGFloat scale)

(2) UIGraphicsBeginImageContext (CGSizeMake (newWidth, newHeight ));

// Use either (1) or (2 ).

[OldImage drawInRect: CGRectMake (0, 0, newWidth, newHeight)];

UIImage * newImage = UIGraphicsGetImageFromCurrentImageContext ();

UIGraphicsEndImageContext ();

Return newImage;

2. Crop UIImage

// Bounds (NSRect): where x and y are the starting point and width and height are the size of the captured image.

CGImageRef imageRef = CGImageCreateWithImageInRect ([oldImage CGImage], bounds );

UIImage * newImage = [UIImage imageWithCGImage: imageRef];

CGImageRelease (imageRef );

Return newImage;