iOS pdf在特定坐标处缩放

Question

我创建了一个 Ios 应用程序，用于按照 Apple pdf 缩放功能阅读 pdf 文档
https://developer.apple.com/library/ios/samplecode/zoomingpdfviewer/Introduction/Intro.html

但是，我不知道如何在特定坐标处自动缩放 pdf 页面，

我的意思是，当我执行加载方法时，pdf 页面会在特定坐标(x, y)处缩放，例如:(10, 20)

有人帮助我吗？请 !

谢谢!

Answer 1

From Apple's Sample Code of Zooming PDF Viewer

UIScrollView 有 API 可以做到这一点

 [yourScrollView zoomToRect:CGRectMake(X, Y, Width, Height) animated:YES];

基本上，如果您想查看更改时的动画，那么您可以将代码放入 View did Appear 方法中。

#import "ZoomingPDFViewerViewController.h"
#import "PDFScrollView.h"
#import <QuartzCore/QuartzCore.h>

@implementation ZoomingPDFViewerViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    /*
     Open the PDF document, extract the first page, and pass the page to the PDF scroll view.
     */
    NSURL *pdfURL = [[NSBundle mainBundle] URLForResource:@"TestPage" withExtension:@"pdf"];

    CGPDFDocumentRef PDFDocument = CGPDFDocumentCreateWithURL((__bridge CFURLRef)pdfURL);

    CGPDFPageRef PDFPage = CGPDFDocumentGetPage(PDFDocument, 1);
    [(PDFScrollView *)self.view setPDFPage:PDFPage];

    CGPDFDocumentRelease(PDFDocument);                
}

-(void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];

    // 1. Get the Scroll View
    UIScrollView *scrollView =  (UIScrollView*)self.view;

    // 2. Zoom to specified rect
    [scrollView zoomToRect:CGRectMake(X, Y, Width, Height) animated:YES];


}