iOS下PDF文件的浏览和涂鸦效果的简单实现

浏览PDF的效果
方法一：利用webview

-(void)loadDocument:(NSString *)documentName inView:(UIWebView *)webView  

{  

    NSString *path = [[NSBundle mainBundle] pathForResource:documentName ofType:nil];  

    NSURL *url = [NSURL fileURLWithPath:path];  

    NSURLRequest *request = [NSURLRequest requestWithURL:url];  

    [webView loadRequest:request];  

} 

利：1.实现简单
        2.还是实现简单
弊：1.仅能浏览，拿不到任何回调，safari不会鸟任何人。
        2.固定竖版拖动，想实现翻页动效果就扒瞎

下面的方法可以解决webview 显示pdf的弊，相对的，要付出一些汗水作为代价了。

方法二：利用CGContextDrawPDFPage

CGPDFDocumentRef GetPDFDocumentRef(NSString *filename)  

{  

    CFStringRef path;  

    CFURLRef url;  

    CGPDFDocumentRef document;  

    size_t count;  

      

    path = CFStringCreateWithCString (NULL, [filename UTF8String], kCFStringEncodingUTF8);  

    url = CFURLCreateWithFileSystemPath (NULL, path, kCFURLPOSIXPathStyle, 0);  

      

    CFRelease (path);  

    document = CGPDFDocumentCreateWithURL (url);  

    CFRelease(url);  

    count = CGPDFDocumentGetNumberOfPages (document);  

    if (count == 0) {  

        printf("[%s] needs at least one page!\n", [filename UTF8String]);  

        return NULL;   

    } else {  

        printf("[%ld] pages loaded in this PDF!\n", count);  

    }  

    return document;  

}  

  

void DisplayPDFPage (CGContextRef myContext, size_t pageNumber, NSString *filename)  

{  

    CGPDFDocumentRef document;  

    CGPDFPageRef page;  

      

    document = GetPDFDocumentRef (filename);  

    page = CGPDFDocumentGetPage (document, pageNumber);  

    CGContextDrawPDFPage (myContext, page);  

    CGPDFDocumentRelease (document);  

} 

这样显示出来的pdf单页是倒立的，Quartz坐标系和UIView坐标系不一样所致，调整坐标系，使pdf正立：

CGContextRef context = UIGraphicsGetCurrentContext();  

CGContextTranslateCTM(context, 80, self.frame.size.height-60);  

CGContextScaleCTM(context, 1, -1); 

配合iOS5强大的UIPageViewController实现翻页浏览

- (PDFViewController *)viewControllerAtIndex:(NSUInteger)index   

{  

    //Return the PDFViewController for the given index.  

    if (([self.pagePDF count] == 0 )|| (index > [self.pagePDF count]) ) {  

        return nil;  

    }  

      

    //Create a new view controller and pass suitable data.  

    PDFViewController *dataViewController = [[PDFViewController alloc]initWithNibName:@"PDFViewController" bundle:nil];  

    //dataViewController.pdfview = [self.pagePDF objectAtIndex:index];  

    dataViewController.pdfview = [[PDFView alloc]initWithFrame:self.view.frame atPage:index];  

    [dataViewController.view addSubview:dataViewController.pdfview];  

    NSLog(@"index = %d",index);  

    return dataViewController;  

}  

  

- (NSUInteger) indexOfViewController:(PDFViewController *)viewController  

{  

    return [self.pagePDF indexOfObject:viewController.pdfview];  

}  

  

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController  

{  

    NSUInteger index = [self indexOfViewController:(PDFViewController *)viewController];  

    if ((index == 0 ) || (index == NSNotFound)){  

        return nil;  

    }  

      

    index--;  

    return  [self viewControllerAtIndex:index];  

}  

  

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController  

{  

    NSUInteger index = [self indexOfViewController:(PDFViewController *)viewController];  

    if (index == NSNotFound)  

    {  

        return nil;  

    }  

      

    index++;  

      

    if (index == [self.pagePDF count]){  

        return  nil;  

    }  

      

    return [self viewControllerAtIndex:index];  

} 

涂鸦效果
主要涉及：
1. 多context，分层画画

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

2. 触摸事件touches族那些event

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event 

……

3. 初始化单页view传页码

- (id)initWithFrame:(CGRect)frame onPage:(NSInteger)page

4.画轨迹方法

CG_EXTERN void CGPathMoveToPoint(CGMutablePathRef path,

  const CGAffineTransform *m, CGFloat x, CGFloat y)

CG_EXTERN void CGPathAddLineToPoint(CGMutablePathRef path,

  const CGAffineTransform *m, CGFloat x, CGFloat y)