生成PDF文件

参考：

• Generating PDF Documents
• Apple documentation
• Generating PDF Content

基本上，在iOS中生成PDF有5个步骤：

• 在Documents目录中创建一个新的PDF文件。

• 创建一个图形上下文。

  - (void)setupPDFDocumentNamed:(NSString*)name Width:(float)width Height:(float)height {    _pageSize = CGSizeMake(width, height);    NSString *newPDFName = [NSString stringWithFormat:@"%@.pdf", name];    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);    NSString *documentsDirectory = [paths objectAtIndex:0];    NSString *pdfPath = [documentsDirectory stringByAppendingPathComponent:newPDFName];    UIGraphicsBeginPDFContextToFile(pdfPath, CGRectZero, nil);}

• Begin a New Page

  - (void)beginPDFPage {    UIGraphicsBeginPDFPageWithInfo(CGRectMake(0, 0, _pageSize.width, _pageSize.height), nil);}

• 绘制内容

  绘制文字

  - (CGRect)addText:(NSString*)text withFrame:(CGRect)frame fontSize:(float)fontSize {    UIFont *font = [UIFont systemFontOfSize:fontSize];    CGSize stringSize = [text sizeWithFont:font constrainedToSize:CGSizeMake(_pageSize.width - 2*20-2*20, _pageSize.height - 2*20 - 2*20) lineBreakMode:UILineBreakModeWordWrap];    float textWidth = frame.size.width;    if (textWidth < stringSize.width)        textWidth = stringSize.width;    if (textWidth > _pageSize.width)        textWidth = _pageSize.width - frame.origin.x;    CGRect renderingRect = CGRectMake(frame.origin.x, frame.origin.y, textWidth, stringSize.height);    [text drawInRect:renderingRect             withFont:font       lineBreakMode:UILineBreakModeWordWrap           alignment:UITextAlignmentLeft];    frame = CGRectMake(frame.origin.x, frame.origin.y, textWidth, stringSize.height);    return frame;}

  绘制线条

  - (CGRect)addLineWithFrame:(CGRect)frame withColor:(UIColor*)color {CGContextRef currentContext = UIGraphicsGetCurrentContext();CGContextSetStrokeColorWithColor(currentContext, color.CGColor);// this is the thickness of the lineCGContextSetLineWidth(currentContext, frame.size.height);CGPoint startPoint = frame.origin;CGPoint endPoint = CGPointMake(frame.origin.x + frame.size.width, frame.origin.y);CGContextBeginPath(currentContext);CGContextMoveToPoint(currentContext, startPoint.x, startPoint.y);CGContextAddLineToPoint(currentContext, endPoint.x, endPoint.y);CGContextClosePath(currentContext);    CGContextDrawPath(currentContext, kCGPathFillStroke);return frame;}

  绘制图片

  - (CGRect)addImage:(UIImage*)image atPoint:(CGPoint)point {CGRect imageFrame = CGRectMake(point.x, point.y, image.size.width, image.size.height);[image drawInRect:imageFrame];return imageFrame;}

• 结束文件

  - (void)finishPDF {    UIGraphicsEndPDFContext();}

完整的调用过程：

- (IBAction)didClickMakePDF {    [self setupPDFDocumentNamed:@"NewPDF" Width:850 Height:1100];    [self beginPDFPage];    CGRect textRect = [self addText:@"This is some nice text here, don't you agree?"                           withFrame:CGRectMake(kPadding, kPadding, 400, 200) fontSize:48.0f];    CGRect blueLineRect = [self addLineWithFrame:CGRectMake(kPadding, textRect.origin.y + textRect.size.height + kPadding, _pageSize.width - kPadding*2, 4)                                        withColor:[UIColor blueColor]];    UIImage *anImage = [UIImage imageNamed:@"tree.jpg"];    CGRect imageRect = [self addImage:anImage                               atPoint:CGPointMake((_pageSize.width/2)-(anImage.size.width/2), blueLineRect.origin.y + blueLineRect.size.height + kPadding)];    [self addLineWithFrame:CGRectMake(kPadding, imageRect.origin.y + imageRect.size.height + kPadding, _pageSize.width - kPadding*2, 4)                  withColor:[UIColor redColor]];    [self finishPDF];}

参考此教程来浏览PDF文件：
Reading & Displaying PDF Documents

最终的效果: