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问用CGPDF查找PDF中的超链接
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Stack Overflow用户

提问于 2011-07-25 20:09:06

回答 2查看 2.5K关注 0票数 3

我试图在一个PDF文档中的页面上找到所有的超链接，并在它们之上放置一个UIButton。

我已经找到并玩了下面的脚本，它应该能够做到。它发现超链接和位置，UIButtons，它们不是在链接的顶部。有人能告诉我为什么吗？

我附上了一张图片来显示按钮是如何关闭的。最上面的按钮应该在蓝色的“大都会”文本的顶部，而最下面的按钮应该在上面的文本上，上面写着“S buttons 2008-2009”。

这是我用来查找链接和放置按钮的代码。

    NSMutableArray *rectArrays;
    NSMutableArray *storeURLs;

    CGPDFPageRef pdfPage = CGPDFDocumentGetPage(_pdf, pageNumber);
    CGPDFDictionaryRef pageDictionary = CGPDFPageGetDictionary(pdfPage);

    CGPDFArrayRef outputArray;
    if(!CGPDFDictionaryGetArray(pageDictionary, "Annots", &outputArray)) {
        //break;
    }

    int arrayCount = 0;
    arrayCount = CGPDFArrayGetCount(outputArray);
    if(arrayCount > 0) {
        for(int j = 0; j < arrayCount; ++j) {
            CGPDFObjectRef aDictObj;
            if(!CGPDFArrayGetObject(outputArray, j, &aDictObj)) {
                return;
            }

            CGPDFDictionaryRef annotDict;
            if(!CGPDFObjectGetValue(aDictObj, kCGPDFObjectTypeDictionary, &annotDict)) {
                return;
            }

            CGPDFDictionaryRef aDict;
            if(!CGPDFDictionaryGetDictionary(annotDict, "A", &aDict)) {
                return;
            }

            CGPDFStringRef uriStringRef;
            if(!CGPDFDictionaryGetString(aDict, "URI", &uriStringRef)) {
                return;
            }

            CGPDFArrayRef rectArray;
            if(!CGPDFDictionaryGetArray(annotDict, "Rect", &rectArray)) {
                return;
            }

            int arrayCount = CGPDFArrayGetCount( rectArray );
            CGPDFReal coords[4];
            for(int k = 0; k < arrayCount; ++k) {
                CGPDFObjectRef rectObj;
                if(!CGPDFArrayGetObject(rectArray, k, &rectObj)) {
                    return;
                }

                CGPDFReal coord;
                if(!CGPDFObjectGetValue(rectObj, kCGPDFObjectTypeReal, &coord)) {
                    return;
                }

                coords[k] = coord;
            }

            char *uriString = (char *)CGPDFStringGetBytePtr(uriStringRef);

            NSString *uri = [NSString stringWithCString:uriString encoding:NSUTF8StringEncoding];

            CGRect rect = CGRectMake(coords[0], coords[1], coords[2], coords[3]);

            NSLog(@"Found: %f ; %f => %f x %f", coords[0], coords[1], coords[2], coords[3]);

            CGPDFInteger pageRotate = 0;
            CGPDFDictionaryGetInteger(pageDictionary, "Rotate", &pageRotate); 
            CGRect pageRect = CGRectIntegral( CGPDFPageGetBoxRect(pdfPage, kCGPDFMediaBox));
            if(pageRotate == 90 || pageRotate == 270) {
                CGFloat temp = pageRect.size.width;
                pageRect.size.width = pageRect.size.height;
                pageRect.size.height = temp;
            }

            rect.size.width = rect.size.width - rect.origin.x;
            rect.size.height = rect.size.height - rect.origin.y;

            CGAffineTransform trans = CGAffineTransformIdentity;
            trans = CGAffineTransformTranslate(trans, 0, pageRect.size.height);
            trans = CGAffineTransformScale(trans, 1.0, -1.0);

            rect = CGRectApplyAffineTransform(rect, trans);

            NSURL *url = [NSURL URLWithString:uri];
            [rectArrays addObject:[NSValue valueWithCGRect:rect]];
            [storeURLs addObject:url];

            for(int i = 0; i <= [rectArrays count]; i++) {
                UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
                [button setFrame:rect];
                [button setTitle:@"Link" forState:UIControlStateNormal];
                [[self view] addSubview:button];

                NSLog(@"Added: %f ; %f => %f x %f", button.frame.origin.x, button.frame.origin.y, button.frame.size.width, button.frame.size.height);
            }
        }
    }

编辑：尝试调整缩放因子，但它不起作用。UIButtons的位置仍然是错误的。

CGAffineTransform trans = CGAffineTransformIdentity;
trans = CGAffineTransformTranslate(trans, 0, pageRect.size.height * 1.5);
trans = CGAffineTransformScale(trans, 1.5, -1.5);

编辑我看了一下iPDFDev链接的源代码，现在看来我已经开始定位了。我的纽扣现在太长了。有人知道为什么会这样吗？如果我从viewRext.origin.x中减去viewRect.size.width，按钮就太短了。

这是我的密码。

    CGPDFPageRef pdfPage = CGPDFDocumentGetPage(_pdf, pageNumber);
    CGPDFDictionaryRef pageDictionary = CGPDFPageGetDictionary(pdfPage);

    CGPDFArrayRef outputArray;
    if(!CGPDFDictionaryGetArray(pageDictionary, "Annots", &outputArray)) {
        //break;
    }

    int arrayCount = 0;
    arrayCount = CGPDFArrayGetCount(outputArray);
    if(arrayCount > 0) {
        for(int j = 0; j < arrayCount; ++j) {
            CGPDFObjectRef aDictObj;
            if(!CGPDFArrayGetObject(outputArray, j, &aDictObj)) {
                return;
            }

            CGPDFDictionaryRef annotDict;
            if(!CGPDFObjectGetValue(aDictObj, kCGPDFObjectTypeDictionary, &annotDict)) {
                return;
            }

            CGPDFDictionaryRef aDict;
            if(!CGPDFDictionaryGetDictionary(annotDict, "A", &aDict)) {
                return;
            }

            CGPDFStringRef uriStringRef;
            if(!CGPDFDictionaryGetString(aDict, "URI", &uriStringRef)) {
                return;
            }

            CGPDFArrayRef rectArray;
            if(!CGPDFDictionaryGetArray(annotDict, "Rect", &rectArray)) {
                return;
            }

            int arrayCount = CGPDFArrayGetCount( rectArray );
            CGPDFReal coords[4];
            for(int k = 0; k < arrayCount; ++k) {
                CGPDFObjectRef rectObj;
                if(!CGPDFArrayGetObject(rectArray, k, &rectObj)) {
                    return;
                }

                CGPDFReal coord;
                if(!CGPDFObjectGetValue(rectObj, kCGPDFObjectTypeReal, &coord)) {
                    return;
                }

                coords[k] = coord;
            }

            char *uriString = (char *)CGPDFStringGetBytePtr(uriStringRef);

            NSString *uri = [NSString stringWithCString:uriString encoding:NSUTF8StringEncoding];

            CGRect rect = CGRectMake(coords[0], coords[1], coords[2], coords[3]);

            CGPoint pdfPoint = CGPointMake(rect.origin.x, rect.origin.y);
            CGPoint viewPoint = CGPointMake(0, 0);

            CGRect cropBox = CGPDFPageGetBoxRect(pdfPage, kCGPDFCropBox);

            int rotation = CGPDFPageGetRotationAngle(pdfPage);

            CGRect pageRenderRect;
            switch (rotation) {
                case 90:
                case -270:
                    pageRenderRect = CGRectMake(0, 0, 1024, 768);

                    viewPoint.x = pageRenderRect.size.width * (pdfPoint.y - cropBox.origin.y) / cropBox.size.height;
                    viewPoint.y = pageRenderRect.size.height * (pdfPoint.x - cropBox.origin.x) / cropBox.size.width;
                    break;
                case 180:
                case -180:
                    pageRenderRect = CGRectMake(0, 0, 768, 1024);

                    viewPoint.x = pageRenderRect.size.width * (cropBox.size.width - (pdfPoint.x - cropBox.origin.x)) / cropBox.size.width;
                    viewPoint.y = pageRenderRect.size.height * (pdfPoint.y - cropBox.origin.y) / cropBox.size.height;
                    break;
                case -90:
                case 270:
                    pageRenderRect = CGRectMake(0, 0, 1024, 768);

                    viewPoint.x = pageRenderRect.size.width * (cropBox.size.height - (pdfPoint.y - cropBox.origin.y)) / cropBox.size.height;
                    viewPoint.y = pageRenderRect.size.height * (cropBox.size.width - (pdfPoint.x - cropBox.origin.x)) / cropBox.size.width;
                    break;
                case 0:
                default:
                    pageRenderRect = CGRectMake(0, 0, 768, 1024);

                    viewPoint.x = pageRenderRect.size.width * (pdfPoint.x - cropBox.origin.x) / cropBox.size.width;
                    viewPoint.y = pageRenderRect.size.height * (cropBox.size.height - pdfPoint.y) / cropBox.size.height;
                    break;
            }

            viewPoint.x = viewPoint.x + pageRenderRect.origin.x;
            viewPoint.y = viewPoint.y + pageRenderRect.origin.y;

            CGRect viewRect = CGRectMake(viewPoint.x, viewPoint.y, rect.size.width, rect.size.height - rect.origin.y);
            viewRect = CGRectMake(viewRect.origin.x, viewRect.origin.y - viewRect.size.height, viewRect.size.width, viewRect.size.height);

            UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
            [button setFrame:viewRect];
            [button setBackgroundColor:[UIColor greenColor]];
            [button setAlpha:0.65];
            [button setTag:kPDFLinkButton];
            [[self view] addSubview:button];
        }
    }

编辑：，这是我的最后代码。有关更多信息，请参见iPDFDev的答案。

- (void)getLinksFromPDF:(CGPDFDocumentRef)_pdf withPageNumber:(NSUInteger)pageNumber
{
    CGPDFPageRef pdfPage = CGPDFDocumentGetPage(_pdf, pageNumber);
    CGPDFDictionaryRef pageDictionary = CGPDFPageGetDictionary(pdfPage);

    CGPDFArrayRef outputArray;
    if(!CGPDFDictionaryGetArray(pageDictionary, "Annots", &outputArray)) {
        //break;
    }

    int arrayCount = 0;
    arrayCount = CGPDFArrayGetCount(outputArray);
    if(arrayCount > 0) {
        for(int j = 0; j < arrayCount; ++j) {
            CGPDFObjectRef aDictObj;
            if(!CGPDFArrayGetObject(outputArray, j, &aDictObj)) {
                return;
            }

            CGPDFDictionaryRef annotDict;
            if(!CGPDFObjectGetValue(aDictObj, kCGPDFObjectTypeDictionary, &annotDict)) {
                return;
            }

            CGPDFDictionaryRef aDict;
            if(!CGPDFDictionaryGetDictionary(annotDict, "A", &aDict)) {
                return;
            }

            CGPDFStringRef uriStringRef;
            if(!CGPDFDictionaryGetString(aDict, "URI", &uriStringRef)) {
                return;
            }

            CGPDFArrayRef rectArray;
            if(!CGPDFDictionaryGetArray(annotDict, "Rect", &rectArray)) {
                return;
            }

            int arrayCount = CGPDFArrayGetCount( rectArray );
            CGPDFReal coords[4];
            for(int k = 0; k < arrayCount; ++k) {
                CGPDFObjectRef rectObj;
                if(!CGPDFArrayGetObject(rectArray, k, &rectObj)) {
                    return;
                }

                CGPDFReal coord;
                if(!CGPDFObjectGetValue(rectObj, kCGPDFObjectTypeReal, &coord)) {
                    return;
                }

                coords[k] = coord;
            }

            char *uriString = (char *)CGPDFStringGetBytePtr(uriStringRef);

            NSString *uri = [NSString stringWithCString:uriString encoding:NSUTF8StringEncoding];

            CGPoint lowerLeft = [self convertPDFPointToViewPoint:CGPointMake(coords[0], coords[1])];
            CGPoint upperRight = [self convertPDFPointToViewPoint:CGPointMake(coords[2], coords[3])];

            // This is the rectangle positioned under the link
            CGRect viewRect = CGRectMake(lowerLeft.x, lowerLeft.y, upperRight.x - lowerLeft.x, lowerLeft.y - upperRight.y);

            // Now adjusting the rectangle to be on top of the link
            viewRect = CGRectMake(viewRect.origin.x, viewRect.origin.y - viewRect.size.height, viewRect.size.width, viewRect.size.height);

            NSLog(@"%@", uri);

            UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
            [button setFrame:viewRect];
            [button setBackgroundColor:[UIColor greenColor]];
            [button setAlpha:0.65];
            [button setTag:kPDFLinkButton];
            [[self view] addSubview:button];
        }
    }   
}

- (CGPoint)convertPDFPointToViewPoint:(CGPoint)pdfPoint
{
    CGPoint viewPoint = CGPointMake(0, 0);

    CGPDFPageRef pdfPage = CGPDFDocumentGetPage(pdf, currentPage);

    CGRect cropBox = CGPDFPageGetBoxRect(pdfPage, kCGPDFCropBox);

    int rotation = CGPDFPageGetRotationAngle(pdfPage);

    CGRect pageRenderRect;
    switch (rotation) {
        case 90:
        case -270:
            pageRenderRect = CGRectMake(0, 0, 1024, 768);

            viewPoint.x = pageRenderRect.size.width * (pdfPoint.y - cropBox.origin.y) / cropBox.size.height;
            viewPoint.y = pageRenderRect.size.height * (pdfPoint.x - cropBox.origin.x) / cropBox.size.width;
            break;
        case 180:
        case -180:
            pageRenderRect = CGRectMake(0, 0, 768, 1024);

            viewPoint.x = pageRenderRect.size.width * (cropBox.size.width - (pdfPoint.x - cropBox.origin.x)) / cropBox.size.width;
            viewPoint.y = pageRenderRect.size.height * (pdfPoint.y - cropBox.origin.y) / cropBox.size.height;
            break;
        case -90:
        case 270:
            pageRenderRect = CGRectMake(0, 0, 1024, 768);

            viewPoint.x = pageRenderRect.size.width * (cropBox.size.height - (pdfPoint.y - cropBox.origin.y)) / cropBox.size.height;
            viewPoint.y = pageRenderRect.size.height * (cropBox.size.width - (pdfPoint.x - cropBox.origin.x)) / cropBox.size.width;
            break;
        case 0:
        default:
            pageRenderRect = CGRectMake(0, 0, 768, 1024);

            viewPoint.x = pageRenderRect.size.width * (pdfPoint.x - cropBox.origin.x) / cropBox.size.width;
            viewPoint.y = pageRenderRect.size.height * (cropBox.size.height - pdfPoint.y) / cropBox.size.height;
            break;
    }

    viewPoint.x = viewPoint.x + pageRenderRect.origin.x;
    viewPoint.y = viewPoint.y + pageRenderRect.origin.y;

    return viewPoint;
}

iphone

objective-c

ipad

pdf

hyperlink

回答 2

Stack Overflow用户

回答已采纳

发布于 2011-07-26 08:14:08

链接存储在页面字典中的Annots数组中。当循环遍历Annots数组时，通过验证注释字典中的子类型键来定位链接注释，它必须是" link“(name对象)。如果有链接注释，则验证它是否有存储在A项中的操作。如果它有一个动作，您可以验证它是否是一个web链接，动作字典中的S条目必须有值"URI“(name object)。如果有URI操作，则从操作字典中的URI条目中检索链接。

PDF页面上的注释位置存储在Rect数组中。这是两个相对角的4个值，通常是左下角x，左下角y，右上角x，右上角y。这些值相对于页面媒体框的左下角。必须根据这些变量在视图坐标中转换这些值: 1.显示页面的视图中的位置；2.显示页面的视图中的大小(当前缩放因子* PDF页面大小)；3.页面裁剪框；4.页面旋转。

转换方法如下所示：

- (CGPoint)convertPDFPointToViewPoint:(CGPoint)pdfPoint {
    CGPoint viewPoint = CGPointMake(0, 0);

    CGRect cropBox = CGPDFPageGetBoxRect(pdfPage, kCGPDFCropBox);

    int rotation = CGPDFPageGetRotationAngle(pdfPage);

    switch (rotation) {
        case 90:
        case -270:
            viewPoint.x = pageRenderRect.size.width * (pdfPoint.y - cropBox.origin.y) / cropBox.size.height;
            viewPoint.y = pageRenderRect.size.height * (pdfPoint.x - cropBox.origin.x) / cropBox.size.width;
            break;
        case 180:
        case -180:
            viewPoint.x = pageRenderRect.size.width * (cropBox.size.width - (pdfPoint.x - cropBox.origin.x)) / cropBox.size.width;
            viewPoint.y = pageRenderRect.size.height * (pdfPoint.y - cropBox.origin.y) / cropBox.size.height;
            break;
        case -90:
        case 270:
            viewPoint.x = pageRenderRect.size.width * (cropBox.size.height - (pdfPoint.y - cropBox.origin.y)) / cropBox.size.height;
            viewPoint.y = pageRenderRect.size.height * (cropBox.size.width - (pdfPoint.x - cropBox.origin.x)) / cropBox.size.width;
            break;
        case 0:
        default:
            viewPoint.x = pageRenderRect.size.width * (pdfPoint.x - cropBox.origin.x) / cropBox.size.width;
            viewPoint.y = pageRenderRect.size.height * (cropBox.size.height - pdfPoint.y) / cropBox.size.height;
            break;
    }

    viewPoint.x = viewPoint.x + pageRenderRect.origin.x;
    viewPoint.y = viewPoint.y + pageRenderRect.origin.y;

    return viewPoint;
}

其中pageRenderRect是显示页面的视图中的矩形。您可以在这里找到其他参考源代码：http://ipdfdev.com/2011/06/21/links-navigation-in-a-pdf-document-on-iphone-and-ipad/

票数 4

Stack Overflow用户

发布于 2011-07-26 04:55:24

猜测一下，您是否应用了某种经过计算的转换来将PDF内容扩展到您拥有的任何框架，但却未能将其应用于按钮框架？您似乎已经将转换硬编码到代码中，该代码假设PDF将被呈现为一个源点等于一个目标点，如果您正在缩放PDF，那么显然不会出现这种情况。

这一诊断可以解释为什么这些按钮看起来像是要覆盖“大都会”和“Saesonen 2008-2009”，但它们的坐标系统已经缩小到左上角。

票数 1

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/6821712

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