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)