kmpdfkit_demo/PDFViewer/Source/PDFView/PDFMagnifierView.m

//
//  PDFMagnifierView.m
//  PDFReader
//
//  Copyright © 2014-2022 PDF Technologies, Inc. All Rights Reserved.
//
//  The PDF Reader Sample applications are licensed with a modified BSD license.
//  Please see License for details. This notice may not be removed from this file.
//

#import "PDFMagnifierView.h"

@implementation PDFMagnifierView

#pragma mark - Initializers

- (instancetype)init {
    if (self = [super initWithFrame:CGRectMake(0, 0, 145, 59)]) {
        self.backgroundColor = [UIColor clearColor];
        self.scale = 1.0;
    }
    return self;
}

- (void)dealloc {
    _viewToMagnify = nil;
    [super dealloc];
}

#pragma mark - Accessors

- (void)setStyle:(PDFMagnifierViewStyle)style {
    _style = style;
    if (PDFMagnifierViewStyleRect == style) {
        self.frame = CGRectMake(0, 0, 145, 59);
    } else if (PDFMagnifierViewStyleCircle == style) {
        self.frame = CGRectMake(0, 0, 127, 127);
    }
}

#pragma mark - Draw

- (void)drawRect:(CGRect)rect {
    if (PDFMagnifierViewStyleRect == self.style) {
        CGContextRef context = UIGraphicsGetCurrentContext();
        UIImage *image = [UIImage imageNamed:@"magnifier-ranged-lo.png" inBundle:[NSBundle bundleForClass:self.class] compatibleWithTraitCollection:nil];
        [image drawInRect:self.bounds];
        
        UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, 0);
        CGContextRef mirrorContext = UIGraphicsGetCurrentContext();
        CGContextTranslateCTM(mirrorContext, self.bounds.size.width/2.0, self.bounds.size.height/2.0-2);
        CGContextScaleCTM(mirrorContext, self.scale, -self.scale);
        CGContextTranslateCTM(mirrorContext, -self.pointToMagnify.x, -self.pointToMagnify.y);
        [self.viewToMagnify.layer renderInContext:mirrorContext];
        
        UIImage *maskImage =  [UIImage imageNamed:@"magnifier-ranged-mask.png" inBundle:[NSBundle bundleForClass:self.class] compatibleWithTraitCollection:nil];
        CGImageRef imageRef = CGBitmapContextCreateImage(mirrorContext);
        CGImageRef maskImageRef = CGImageCreateWithMask(imageRef, maskImage.CGImage);
        CGImageRelease(imageRef);
        UIGraphicsEndImageContext();
        CGContextDrawImage(context, self.bounds, maskImageRef);
        CGImageRelease(maskImageRef);
        
        image = [UIImage imageNamed:@"magnifier-ranged-hi.png" inBundle:[NSBundle bundleForClass:self.class] compatibleWithTraitCollection:nil];
        [image drawInRect:self.bounds];
    } else if (PDFMagnifierViewStyleCircle == self.style) {
        CGContextRef context = UIGraphicsGetCurrentContext();
        UIImage *image = [UIImage imageNamed:@"loupe-lo.png" inBundle:[NSBundle bundleForClass:self.class] compatibleWithTraitCollection:nil];
        [image drawInRect:self.bounds];
        
        UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, 0);
        CGContextRef mirrorContext = UIGraphicsGetCurrentContext();
        CGContextTranslateCTM(mirrorContext, self.bounds.size.width/2.0, self.bounds.size.height/2.0);
        CGContextScaleCTM(mirrorContext, self.scale, -self.scale);
        CGContextTranslateCTM(mirrorContext, -self.pointToMagnify.x, -self.pointToMagnify.y);
        [self.viewToMagnify.layer renderInContext:mirrorContext];
        
        UIImage *maskImage =  [UIImage imageNamed:@"loupe-mask.png" inBundle:[NSBundle bundleForClass:self.class] compatibleWithTraitCollection:nil];
        CGImageRef imageRef = CGBitmapContextCreateImage(mirrorContext);
        CGImageRef maskImageRef = CGImageCreateWithMask(imageRef, maskImage.CGImage);
        CGImageRelease(imageRef);
        UIGraphicsEndImageContext();
        CGContextDrawImage(context, self.bounds, maskImageRef);
        CGImageRelease(maskImageRef);
        
//        image = [UIImage imageNamed:@"loupe-hi.png" inBundle:[NSBundle bundleForClass:self.class] compatibleWithTraitCollection:nil];
//        [image drawInRect:self.bounds];
    }
}

@end