CG PDF ViewController 和多页 PDF（缩放）

Posted 2023-03-16

【中文标题】CG PDF ViewController 和多页 PDF（缩放）

【英文标题】：CGPDFViewController and multipage PDF (zomming)

【发布时间】：2011-05-04 07:02:10

【问题描述】：

我正在尝试为 ios 创建一个基本的 PDF 查看器，但我几乎陷入了困境。我只希望它能够查看 PDF 并跳转到特定页面。

这是我到目前为止所做的：

#import "SFPDFViewerController.h"
#import <QuartzCore/QuartzCore.h>

@implementation SFPDFViewerController
@synthesize currentPageIndex;

- (void)viewDidLoad

    currentPageIndex = 1;

    myDocumentRef = CGPDFDocumentCreateWithURL((CFURLRef)[NSURL URLWithString:@"file:///Users/soulstorm/Desktop/Basic%20UNIX%20Tutorial.pdf"]);
    myPageRef = CGPDFDocumentGetPage(myDocumentRef, currentPageIndex);
    //CGRect pageRect = CGRectIntegral(CGPDFPageGetBoxRect(myPageRef, kCGPDFCropBox));
    CGRect pageRect = self.view.bounds;

    CATiledLayer *tiledLayer = [CATiledLayer layer];
    tiledLayer.delegate = self;
    tiledLayer.tileSize = CGSizeMake(200.0, 200.0);
    tiledLayer.levelsOfDetail = 1000;
    tiledLayer.levelsOfDetailBias = 1000;
    tiledLayer.frame = pageRect;

    myContentView = [[UIView alloc] initWithFrame:pageRect];
    [myContentView.layer addSublayer:tiledLayer];

    CGRect viewFrame = self.view.frame;
    viewFrame.origin = CGPointZero;
    viewFrame.size.height-= 44;

    scrollView = [[UIScrollView alloc] initWithFrame:viewFrame];
    scrollView.delegate = self;
    scrollView.contentSize = pageRect.size;
    scrollView.maximumZoomScale = 3.0;
    [scrollView addSubview:myContentView];

    [self.view addSubview:scrollView];

    [self.view setBackgroundColor:[UIColor whiteColor]];
    [scrollView setBackgroundColor:[UIColor whiteColor]];


- (void)viewDidUnload

    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;


- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView

    return myContentView;


- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx

    NSLog(@"draw layer...");
    CGContextSetRGBFillColor(ctx, 1.0, 1.0, 1.0, 1.0);
    CGContextFillRect(ctx, CGContextGetClipBoundingBox(ctx));
    CGContextTranslateCTM(ctx, 0.0, layer.bounds.size.height);
    CGContextScaleCTM(ctx, 1.0, -1.0);
    CGContextConcatCTM(ctx, CGPDFPageGetDrawingTransform(myPageRef, kCGPDFCropBox, layer.bounds, 0, true));
    CGContextDrawPDFPage(ctx, myPageRef);


#pragma mark - Functions
- (IBAction)goToNextPage:(id)sender

    [self displayNextPage];

- (IBAction)goToPreviewsPage:(id)sender

    [self displayPreviewsPage];


- (void)displayNextPage

    currentPageIndex++;
    [self reloadCurrentPage];

- (void)displayPreviewsPage

    currentPageIndex--;
    [self reloadCurrentPage];

- (void)reloadCurrentPage

    NSLog(@"reloading current page... %i", currentPageIndex);
    myPageRef = CGPDFDocumentGetPage(myDocumentRef, currentPageIndex);
    //[self.view setNeedsDisplay];
    //[self.view.layer setNeedsDisplay];
    //[myContentView.layer setNeedsDisplay];

#pragma mark -
- (void)dealloc

    [myContentView release];
    myContentView = nil;
    CGPDFDocumentRelease(myDocumentRef);
    myDocumentRef = NULL;
    myPageRef = NULL;
    [super dealloc];

@end

上面的代码正确显示了PDF的第一页，但是当我尝试转到下一页时，它会停留在第一页上，有时在缩放时我可以看到第二页的部分内容。

谁能指出我正确的方向？

【参考方案1】：

Apple 的 ZoomingPDFViewer 提供了一个简单的示例。 http://developer.apple.com/library/ios/#samplecode/ZoomingPDFViewer/Introduction/Intro.html