IOS图像处理（8）在PDF中绘图

浏览数：30 / 时间：2015年06月11日

绘制到PDF则要启用pdf图形上下文，PDF图形上下文的创建使用方式跟位图图形上下文是类似的，需要注意的一点就是绘制内容到PDF时需要创建分页，每页内容的开始都要调用一次UIGraphicsBeginPDFPage方法。下面的示例演示了文本绘制和图片绘制（其他图形绘制也是类似的）：

- (void)viewDidLoad
{
    [super viewDidLoad];
    //沙盒路径
    NSArray *pathArray = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
    NSString *path=[[pathArray firstObject] stringByAppendingPathComponent:@"myPDF.pdf"];
    
    //path:保存路径
    //bounds:pdf文档大小，如果设置为CGRectZero则使用默认值：612*792
    //pageInfo:页面设置,为nil则不设置任何信息
    UIGraphicsBeginPDFContextToFile(path, CGRectZero, @{kCGPDFContextAuthor:@"zlt"});

    //也可以存储到NSMutableData中
    //UIGraphicsBeginPDFContextToData(<#NSMutableData *data#>, <#CGRect bounds#>, <#NSDictionary *documentInfo#>);
    
    //开始第一页绘制
    UIGraphicsBeginPDFPage();
    
    NSString *title = @"Welcome to Apple Support";
    //段落样式
    NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
    //对齐方式
    NSTextAlignment aligment = NSTextAlignmentCenter;
    style.alignment = aligment;
    [title drawInRect:CGRectMake(26, 20, 300, 50) withAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:18],NSParagraphStyleAttributeName:style}];
    
    NSString *content = @"Learn about Apple products, view online manuals, get the latest downloads, and more. Connect with other Apple users, or get service, support, and professional advice from Apple.";
    NSMutableParagraphStyle *style2 = [[NSMutableParagraphStyle alloc] init];
    style2.alignment = NSTextAlignmentLeft;
    [content drawInRect:CGRectMake(26, 56, 300, 255) withAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:15],NSForegroundColorAttributeName:[UIColor grayColor],NSParagraphStyleAttributeName:style2}];
    
    UIImage *image = [UIImage imageNamed:@"applecare_folks_tall.png"];
    [image drawInRect:CGRectMake(316, 20, 290, 305)];
    
    UIImage *image2 = [UIImage imageNamed:@"applecare_page1.png"];
    [image2 drawInRect:CGRectMake(6, 320, 600, 281)];
    
    //创建新的一页继续绘制其他内容
    UIGraphicsBeginPDFPage();
    UIImage *image3 = [UIImage imageNamed:@"applecare_page2.png"];
    [image3 drawInRect:CGRectMake(6, 20, 600, 629)];
    
    //结束pdf上下文
    UIGraphicsEndPDFContext();

}