kmpdfkit_demo/PDFViewer/Source/PDFWatermark/PDFWatermarkDrawView.m

//
//  CPDFDrawView.m
//  PDFViewer
//
//  Created by kdanmobile_2 on 2022/12/22.
//

#import "PDFWatermarkDrawView.h"

@implementation PDFWatermarkDrawView

- (instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    
    if (self) {
        self.backgroundColor = [UIColor clearColor];
        
        _dataModel = [[PDFWatermarkDataModel alloc] init];
        
        _horizontal = 100;
        _vertical = 100;
    }
    
    return self;
}

- (void)drawRect:(CGRect)rect {
    [super drawRect:rect];
    
    CGContextRef context = UIGraphicsGetCurrentContext();

    if (self.dataModel.text) {
        [self drawText:context];
    } else if (self.dataModel.image) {
        [self drawImage:context];
    }
}

- (void)drawText:(CGContextRef)context {
    CGContextSetFillColorWithColor(context, self.dataModel.textColor.CGColor);
    CGContextSaveGState(context);
    
    CGContextSetAlpha(context, self.dataModel.watermarkOpacity);
    
    UIFont *font = [UIFont systemFontOfSize:20 * self.dataModel.watermarkScale];
    NSDictionary *dic = @{NSFontAttributeName:font,NSForegroundColorAttributeName:self.dataModel.textColor};
    
    NSInteger wx,wy,height,width;
    wx = self.waterLabelRect.origin.x + self.documentViewRect.origin.x;
    wy = self.waterLabelRect.origin.y + self.documentViewRect.origin.y;
    height = self.waterLabelRect.size.height + self.dataModel.verticalSpacing / 2.5;
    width = self.waterLabelRect.size.width + self.dataModel.horizontalSpacing / 2.1;

    NSInteger x,y,a,b;
    x = self.frame.size.width / width;
    y = self.frame.size.height / height;

    a = wx % width;
    b = wy % height;
    
    CGFloat ctm = (self.dataModel.watermarkRotation * M_PI) / 180;
    
    CGContextTranslateCTM(context, self.center.x,  self.center.y);
    
    CGContextRotateCTM(context, ctm);

    for (NSInteger i = 0; i < x; i++) {
        for (NSInteger j = 0; j < y; j++) {
            
            [self.dataModel.text drawInRect:CGRectMake((a + i * width) - self.center.x, b + j * height - self.center.y, width - self.dataModel.horizontalSpacing / 2.5, height - self.dataModel.verticalSpacing / 2.5) withAttributes:dic];
        }
    }
    
    CGContextRotateCTM(context, -ctm);
    CGContextTranslateCTM(context, - self.center.x, - self.center.y);
}

- (void)drawImage:(CGContextRef)context {
    CGContextSaveGState(context);
    
    CGContextSetAlpha(context, self.dataModel.watermarkOpacity);
    
    NSInteger wx,wy,height,width;
    wx = self.waterLabelRect.origin.x + self.documentViewRect.origin.x;
    wy = self.waterLabelRect.origin.y + self.documentViewRect.origin.y;
    height = self.waterLabelRect.size.height + self.dataModel.verticalSpacing / 1.8;
    width = self.waterLabelRect.size.width + self.dataModel.horizontalSpacing / 1.8;

    NSInteger x,y,a,b;
    x = self.frame.size.width / width;
    y = self.frame.size.height / height;

    a = wx % width;
    b = wy % height;
    
    CGFloat ctm = (self.dataModel.watermarkRotation * M_PI) / 180;
    
    CGContextTranslateCTM(context, self.center.x,  self.center.y);
    
    CGContextRotateCTM(context, ctm);

    for (NSInteger i = 0; i < x; i++) {
        for (NSInteger j = 0; j < y; j++) {
            
            [self.dataModel.image drawInRect:CGRectMake((a + i * width) - self.center.x, b + j * height - self.center.y, width - self.dataModel.horizontalSpacing / 1.8, height - self.dataModel.verticalSpacing / 1.8) blendMode:kCGBlendModeNormal alpha:self.dataModel.watermarkOpacity];
        }
    }
    CGContextRotateCTM(context, -ctm);
    
    CGContextTranslateCTM(context, - self.center.x, - self.center.y);
}

@end