使用Quartz将PDF文档保存到磁盘 [英] Saving a PDF document to disk using Quartz

问题描述

我试图绘制一个pdf页面到pdf上下文，然后保存到磁盘。我似乎不知道什么是错的。有人可以给我一些指针。感谢。

   - （void）testQuartz：（NSData *）pdfDocumentData 
 {
 //创建pdf文档参考
 CGDataProviderRef dataProvider = CGDataProviderCreateWithCFData（（CFDataRef）pdfDocumentData）; 
 CGPDFDocumentRef document = CGPDFDocumentCreateWithProvider（dataProvider）; 
 CGDataProviderRelease（dataProvider）; //释放数据提供者
 
 //创建pdf上下文
 CGPDFPageRef page = CGPDFDocumentGetPage（document，0）; 
 CGRect pageRect = CGPDFPageGetBoxRect（page，kCGPDFMediaBox）; 
 CFMutableDataRef mutableData = CFDataCreateMutable（NULL，0）; 
 
 CGDataConsumerRef dataConsumer = CGDataConsumerCreateWithCFData（mutableData）; 
 CGContextRef pdfContext = CGPDFContextCreate（dataConsumer，& pageRect，NULL）; 
 
 if（CGPDFDocumentGetNumberOfPages（document）> 0）
 {
 //将页面绘制到新上下文
 page = CGPDFDocumentGetPage（document，0）; 
 CGContextDrawPDFPage（pdfContext，page）; 
} 
 else 
 {
 NSLog（@无法创建文档）; 
} 
 
 //写入磁盘
 [（NSMutableData *）mutableData writeToFile：@/ Users / David / Desktop / test.pdfatomically：YES]; 
 
 //清理
 CGDataConsumerRelease（dataConsumer）; 
 CFRelease（mutableData）; 
 CGPDFDocumentRelease（document）; 
} 
  

解决方案

用它。

1. PDF页面从1开始而不是0。


2. 需要告诉pdf上下文页面开始和结束。


3. 在将数据写入磁盘之前，请释放pdf上下文。


以下是修正后的程式码。

   - （void）testQuartz：（NSData *）pdfDocumentData 
 {
 //创建pdf文档引用
 CGDataProviderRef dataProvider = CGDataProviderCreateWithCFData ）pdfDocumentData）; 
 CGPDFDocumentRef document = CGPDFDocumentCreateWithProvider（dataProvider）; 
 
 //创建pdf上下文
 CGPDFPageRef page = CGPDFDocumentGetPage（document，1）; //页面从1开始编号
 CGRect pageRect = CGPDFPageGetBoxRect（page，kCGPDFMediaBox）; 
 CFMutableDataRef mutableData = CFDataCreateMutable（NULL，0）; 
 
 //NSLog(@\"w:%2.2f，h：％2.2f，pageRect.size.width，pageRect.size.height）; 
 CGDataConsumerRef dataConsumer = CGDataConsumerCreateWithCFData（mutableData）; 
 CGContextRef pdfContext = CGPDFContextCreate（dataConsumer，& pageRect，NULL）; 
 
 
 if（CGPDFDocumentGetNumberOfPages（document）> 0）
 {
 //将页面绘制到新上下文
 // page = CGPDFDocumentGetPage文件，1）; //页面从1开始编号
 
 CGPDFContextBeginPage（pdfContext，NULL）; 
 CGContextDrawPDFPage（pdfContext，page）; 
 CGPDFContextEndPage（pdfContext）; 
} 
 else 
 {
 NSLog（@无法创建文档）; 
} 
 
 CGContextRelease（pdfContext）; //在将数据写入磁盘之前释放。 
 
 //写入磁盘
 [（NSData *）mutableData writeToFile：@/ Users / David / Desktop / test.pdfatomically：YES]; 
 
 //清理
 CGDataProviderRelease（dataProvider）; //释放数据提供者
 CGDataConsumerRelease（dataConsumer）; 
 CGPDFDocumentRelease（document）; 
 CFRelease（mutableData）; 
} 
  




I am trying to draw a pdf page onto a pdf context and then save it to disk. I cannot seem to figure out what is wrong. Can someone give me a few pointers. Thanks.

- (void)testQuartz:(NSData *)pdfDocumentData
{   
    //Create the pdf document reference
    CGDataProviderRef dataProvider = CGDataProviderCreateWithCFData((CFDataRef)pdfDocumentData);
    CGPDFDocumentRef document = CGPDFDocumentCreateWithProvider(dataProvider);
    CGDataProviderRelease(dataProvider); //Release the data provider

    //Create the pdf context
    CGPDFPageRef page = CGPDFDocumentGetPage(document, 0);
    CGRect pageRect = CGPDFPageGetBoxRect(page, kCGPDFMediaBox);
    CFMutableDataRef mutableData = CFDataCreateMutable(NULL, 0);

    CGDataConsumerRef dataConsumer = CGDataConsumerCreateWithCFData(mutableData);
    CGContextRef pdfContext = CGPDFContextCreate(dataConsumer, &pageRect, NULL);

    if (CGPDFDocumentGetNumberOfPages(document) > 0)
    {       
        //Draw the page onto the new context
        page = CGPDFDocumentGetPage(document, 0);
        CGContextDrawPDFPage(pdfContext, page);
    }
    else
    {
        NSLog(@"Failed to create the document");
    }

    //Write to disk
    [(NSMutableData *)mutableData writeToFile:@"/Users/David/Desktop/test.pdf" atomically:YES];

    //Clean up
    CGDataConsumerRelease(dataConsumer);
    CFRelease(mutableData);
    CGPDFDocumentRelease(document);
}

解决方案

So I found 3 things wrong with it.

1. PDF pages start at 1 and not 0.
2. Need to tell the pdf context when a page begins and ends.
3. Release the pdf context prior to writing the data to disk. This is key for some reason.

Here is the corrected code that works.

- (void)testQuartz:(NSData *)pdfDocumentData
{       
    //Create the pdf document reference
    CGDataProviderRef dataProvider = CGDataProviderCreateWithCFData((CFDataRef)pdfDocumentData);
    CGPDFDocumentRef document = CGPDFDocumentCreateWithProvider(dataProvider);

    //Create the pdf context
    CGPDFPageRef page = CGPDFDocumentGetPage(document, 1); //Pages are numbered starting at 1
    CGRect pageRect = CGPDFPageGetBoxRect(page, kCGPDFMediaBox);
    CFMutableDataRef mutableData = CFDataCreateMutable(NULL, 0);

    //NSLog(@"w:%2.2f, h:%2.2f",pageRect.size.width, pageRect.size.height);
    CGDataConsumerRef dataConsumer = CGDataConsumerCreateWithCFData(mutableData);
    CGContextRef pdfContext = CGPDFContextCreate(dataConsumer, &pageRect, NULL);


    if (CGPDFDocumentGetNumberOfPages(document) > 0)
    {       
        //Draw the page onto the new context
        //page = CGPDFDocumentGetPage(document, 1); //Pages are numbered starting at 1

        CGPDFContextBeginPage(pdfContext, NULL);
        CGContextDrawPDFPage(pdfContext, page);
        CGPDFContextEndPage(pdfContext);
    }
    else
    {
        NSLog(@"Failed to create the document");
    }

    CGContextRelease(pdfContext); //Release before writing data to disk.

    //Write to disk
    [(NSData *)mutableData writeToFile:@"/Users/David/Desktop/test.pdf" atomically:YES];

    //Clean up
    CGDataProviderRelease(dataProvider); //Release the data provider
    CGDataConsumerRelease(dataConsumer);
    CGPDFDocumentRelease(document);
    CFRelease(mutableData);
}

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