Why is a CGPDFDocumentRef showing blurry lines on the view? (See Image)

Question

I have a very strange and particular case on which I want to show a PDF on the screen. However, the problem is that my document is showing blurry lines, not shown on the program Acrobat Pro.

Watch this image:

https://i.stack.imgur.com/D7GWF.jpg

Is this something I can fix (blurry lines) with CGContext or is it a resolution problem. Here is my code:

- (id)initWithFrame:(CGRect)frame {

self = [super initWithFrame:(CGRect)frame];
if (self) {
    self.backgroundColor = [UIColor clearColor];
    NSString *pathToPdfDoc = [[NSBundle mainBundle] pathForResource:@"myPDF" ofType:@"pdf"];
    NSURL *pdfUrl = [NSURL fileURLWithPath:pathToPdfDoc];
    document = CGPDFDocumentCreateWithURL((__bridge CFURLRef)pdfUrl);
    currentPage = 1;

}

return self;
}

+ (void) renderPage: (CGPDFPageRef) page inContext: (CGContextRef) context{
[viewPDF renderPage:page inContext:context atPoint:CGPointMake(0, 0)];
}

+ (void) renderPage: (CGPDFPageRef) page inContext: (CGContextRef) context atPoint:(CGPoint) point{
[viewPDF renderPage:page inContext:context atPoint:point withZoom:100];
}

+ (void) renderPage: (CGPDFPageRef) page inContext: (CGContextRef) context atPoint: (CGPoint) point withZoom: (float) zoom{

CGRect cropBox = CGPDFPageGetBoxRect(page, kCGPDFCropBox);
int rotate = CGPDFPageGetRotationAngle(page);

CGContextSaveGState(context);

// Setup the coordinate system.
// Top left corner of the displayed page must be located at the point specified by the 'point' parameter.
CGContextTranslateCTM(context, point.x, point.y);

// Scale the page to desired zoom level.
CGContextScaleCTM(context, zoom / 100, zoom / 100);

// The coordinate system must be set to match the PDF coordinate system.
switch (rotate) {
    case 0:
        CGContextTranslateCTM(context, 0, cropBox.size.height);
        CGContextScaleCTM(context, 1, -1);
        break;
    case 90:
        CGContextScaleCTM(context, 1, -1);
        CGContextRotateCTM(context, -M_PI / 2);
        break;
    case 180:
    case -180:
        CGContextScaleCTM(context, 1, -1);
        CGContextTranslateCTM(context, cropBox.size.width, 0);
        CGContextRotateCTM(context, M_PI);
        break;
    case 270:
    case -90:
        CGContextTranslateCTM(context, cropBox.size.height, cropBox.size.width);
        CGContextRotateCTM(context, M_PI / 2);
        CGContextScaleCTM(context, -1, 1);
        break;
}

// The CropBox defines the page visible area, clip everything outside it.
CGRect clipRect = CGRectMake(0, 0, cropBox.size.width, cropBox.size.height);
CGContextAddRect(context, clipRect);
CGContextClip(context);

CGContextSetRGBFillColor(context, 1.0, 1.0, 1.0, 1.0);


CGContextSetLineJoin(context, kCGLineJoinRound);

CGContextFillRect(context, clipRect);

CGContextTranslateCTM(context, -cropBox.origin.x, -cropBox.origin.y);

CGContextDrawPDFPage(context, page);

CGContextRestoreGState(context);


}

 + (void) renderPage: (CGPDFPageRef) page inContext: (CGContextRef) context inRectangle: (CGRect) displayRectangle {
if ((displayRectangle.size.width == 0) || (displayRectangle.size.height == 0)) {
    return;
}

CGRect cropBox = CGPDFPageGetBoxRect(page, kCGPDFCropBox);
int pageRotation = CGPDFPageGetRotationAngle(page);

CGSize pageVisibleSize = CGSizeMake(cropBox.size.width, cropBox.size.height);
if ((pageRotation == 90) || (pageRotation == 270) ||(pageRotation == -90)) {
    pageVisibleSize = CGSizeMake(cropBox.size.height, cropBox.size.width);
}

float scaleX = displayRectangle.size.width / pageVisibleSize.width;
float scaleY = displayRectangle.size.height / pageVisibleSize.height;
float scale = scaleX < scaleY ? scaleX : scaleY;

// Offset relative to top left corner of rectangle where the page will be displayed
float offsetX = 0;
float offsetY = 0;

float rectangleAspectRatio = displayRectangle.size.width / displayRectangle.size.height;
float pageAspectRatio = pageVisibleSize.width / pageVisibleSize.height;

if (pageAspectRatio < rectangleAspectRatio) {
    // The page is narrower than the rectangle, we place it at center on the horizontal
    offsetX = (displayRectangle.size.width - pageVisibleSize.width * scale) / 2;
}
else { 
    // The page is wider than the rectangle, we place it at center on the vertical
    offsetY = (displayRectangle.size.height - pageVisibleSize.height * scale) / 2;
}

CGPoint topLeftPage = CGPointMake(displayRectangle.origin.x + offsetX, displayRectangle.origin.y + offsetY);

[viewPDF renderPage:page inContext:context atPoint:topLeftPage withZoom:scale * 100];
}



-(void)drawRect:(CGRect)inRect{                 
if(document) 

{
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    CGPDFPageRef page = CGPDFDocumentGetPage(document, currentPage);
    [viewPDF renderPage:page inContext:ctx  atPoint:CGPointMake(10,10) withZoom:125];


}

Answer 1

Ok. The problem was fixed with the source of the PDF, Finale. The 2012 version now has export to PDF and exports the lines as it should be. The code is left here to help anyone that wants to show a PDF on all the screen