当我在ipad屏幕上触摸时如何获取PDF批注 [英] How to get PDF annotations when i touch on ipad screen
问题描述
我开发了一个使用CATiled Layer在ipad上显示PDF的应用程序.到目前为止，一切都很好但是确实存在一个问题，使我难以为继.我有一个带有嵌入式注释的PDF.每个注释都有一个URL.我可以找到触摸区域的坐标，但是问题是如何找到手指下是否有注释，以及如何提取URL以在浏览器中打开它?
I have developed an application which displays PDF on ipad using CATiled Layer. So far, so good& But there is a problem which really makes me cut my last hairs. I have a PDF with embedded annotations. Each annotation has an URL. I can find the coordinates of touch area but the question is how I can find if there is an annotation under my finger and how to extract URL to open it in browser?
如果任何人都可以分享如何实现的想法，我将非常感谢您的帮助！
If anyone can share any thoughts about how this can be done, I will really appreciate your help!
预先感谢
推荐答案
使用CGPDF获取注释并不是很困难，尽管起初需要我一点儿摆弄.
Getting the annotations isn't very difficult with CGPDF although it required a little fiddling around for me at first.
//Get the current page ref
CGPDFPageRef currentPdfPage = CGPDFDocumentGetPage(pdfDocumentRef, page);
//Get the page dictionary
CGPDFDictionaryRef pageDictionary = CGPDFPageGetDictionary(currentPdfPage);
CGPDFArrayRef annotsArray;
//Get the Annots array
if(!CGPDFDictionaryGetArray(pageDictionary, "Annots", &annotsArray)) {
//DLog(@"No Annots found for page %d", page);
[self updateProgress];
return;
}
int annotsArrayCount = CGPDFArrayGetCount(annotsArray);
//DLog(@"%d annots found for page %d in file %@", annotsArrayCount, page, _fileName);
NSMutableArray* touchRectsArray = [[NSMutableArray alloc] initWithCapacity:annotsArrayCount];
for (int j=annotsArrayCount; j >= 0; j--) {
int destPageNumber = 0;
NSString* uri = nil;
//DLog(@"%d/%d", j+1, annotsArrayCount);
CGPDFObjectRef aDictObj;
if(!CGPDFArrayGetObject(annotsArray, j, &aDictObj)) {
//DLog(@"%@", @"can't get dictionary object");
continue;
}
CGPDFDictionaryRef annotDict;
if(!CGPDFObjectGetValue(aDictObj, kCGPDFObjectTypeDictionary, &annotDict)) {
//DLog(@"%@", @"can't get annotDict");
continue;
}
//------------
CGPDFDictionaryRef aDict;
CGPDFArrayRef destArray;
if(CGPDFDictionaryGetDictionary(annotDict, "A", &aDict)) {
CGPDFStringRef uriStringRef;
if(CGPDFDictionaryGetString(aDict, "URI", &uriStringRef)) {
char* uriString = (char *)CGPDFStringGetBytePtr(uriStringRef);
uri = [NSString stringWithCString:uriString encoding:NSUTF8StringEncoding];
}
} else {
continue;
}
这将为您提供URL. 获取rects:
This will get you the URLs. Getting the rects:
CGPDFArrayRef rectArray;
if(!CGPDFDictionaryGetArray(annotDict, "Rect", &rectArray)) {
DLog(@"%@", @"can't get Rect");
}
int arrayCount = CGPDFArrayGetCount(rectArray);
CGPDFReal coords[4];
for (int k = 0; k < arrayCount; k++) {
CGPDFObjectRef rectObj;
if(!CGPDFArrayGetObject(rectArray, k, &rectObj)) {
DLog(@"%@", @"can't get rect data");
}
CGPDFReal coord;
if(!CGPDFObjectGetValue(rectObj, kCGPDFObjectTypeReal, &coord)) {
DLog(@"%@", @"can't get coords");
}
coords[k] = coord;
}
CGRect drawRect = [[SharedConfig valueForKey:@"screenSize"] CGRectValue];
BOOL drawBoxIsLandscape = NO;
if (1 < drawRect.size.width/drawRect.size.height) {
drawBoxIsLandscape = YES;
}
CGRect pageRect = CGRectIntegral(CGPDFPageGetBoxRect(currentPdfPage, kCGPDFMediaBox));
landscape = NO;
if (1 < pageRect.size.width/pageRect.size.height) {
landscape = YES;
}
float ratio = 0.0;
//Get the rect of the clickable area
//CGRect coordsRect = CGRectMake(coords[0], coords[1], coords[2], coords[3]);
//Transform to new coordinate system
CGRect originalRect = CGRectMake(coords[0], (pageRect.size.height-(coords[3]-coords[1]))-coords[1], coords[2]-coords[0], coords[3]-coords[1]);
CGPDFInteger pageRotate = 0;
CGPDFDictionaryGetInteger(pageDictionary, "Rotate", &pageRotate);
if (pageRotate == 90 || pageRotate == 270) {
CGFloat temp = pageRect.size.width;
pageRect.size.width = pageRect.size.height;
pageRect.size.height = temp;
ratio = drawRect.size.height / pageRect.size.height;
}
if (drawBoxIsLandscape) {
ratio = landscape ? (drawRect.size.height/pageRect.size.height) : (drawRect.size.height/pageRect.size.width);
if (landscape && drawRect.size.width < pageRect.size.width*ratio) {
ratio = drawRect.size.width/pageRect.size.width;
} else if (!landscape && drawRect.size.height < pageRect.size.width*ratio) {
ratio = drawRect.size.height/pageRect.size.width;
}
} else {
ratio = landscape ? (drawRect.size.height/pageRect.size.width) : (drawRect.size.height/pageRect.size.height);
if (landscape && drawRect.size.width < pageRect.size.height*ratio) {
ratio = drawRect.size.width/pageRect.size.height;
} else if (!landscape && drawRect.size.height < pageRect.size.height*ratio) {
ratio = drawRect.size.height/pageRect.size.height;
}
}
CGRect calculatedRect = CGRectMake(originalRect.origin.x*ratio, originalRect.origin.y*ratio, originalRect.size.width*ratio, originalRect.size.height*ratio);
if ((landscape && !drawBoxIsLandscape) || (!landscape && drawBoxIsLandscape)) {
CGFloat width = calculatedRect.size.width;
calculatedRect.size.width = calculatedRect.size.height;
calculatedRect.size.height = width;
CGFloat yModifier = drawRect.size.height-(pageRect.size.width*ratio);
CGFloat x = calculatedRect.origin.x;
calculatedRect.origin.x = calculatedRect.origin.y;
calculatedRect.origin.y = drawRect.size.height-(x+calculatedRect.size.height)-yModifier;
}
if (nil != uri) {
[touchRectsArray addObject:[NSDictionary dictionaryWithObjectsAndKeys:[NSArray arrayWithCGRect:calculatedRect], @"rect", uri, @"targetUrl", nil]];
}
如您所见，这部分代码首先获取注释的矩形，将其转换为设备坐标系，然后根据页面与屏幕的比例，旋转系数等进行一些重新计算，调整大小和重新定位.最后，您将获得该页面的一系列触摸屏区域.为了处理触摸，可以使用以下简单解决方案:
As you can see this bit of code first gets the rectangle of the annotation, transforms it to the device coordinate system, then does some recalculation, sizing and repositioning, based on page to screen ratio, rotation factor, etc. At the end you will have an array of the touch-active areas for that page. For handling the touches the following simple solution can be used:
- (void) tapGesture:(UIGestureRecognizer*)sender
{
if (UIGestureRecognizerStateEnded == sender.state) {
CGPoint touchPoint = [sender locationInView:self.view];
if (nil != self.touchRects) for (int i=0; i<[self.touchRects count]; i++) {
if (CGRectContainsPoint([[[self.touchRects objectAtIndex:i] objectForKey:@"rect"] CGRectValue], touchPoint)) {
if ([[self.touchRects objectAtIndex:i] objectForKey:@"targetUrl"]) {
NSString* targetUrl = [[self.touchRects objectAtIndex:i] objectForKey:@"targetUrl"];
DLog(@"Hit found for target url: %@", targetUrl);
NSURL* url = [NSURL URLWithString:targetUrl];
[[UIApplication sharedApplication] openURL:url];
} return;
}
}
DLog(@"No hit found for touch at %@", NSStringFromCGPoint(touchPoint));
}
}
这篇关于当我在ipad屏幕上触摸时如何获取PDF批注的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
