Question

我编写了以下代码片段。当用户在图像上点击两次（gesturerecognizer）时，它会添加注释。它成功添加了注释，但它并不完全是用户tapps的位置。点击点和注释图像位置之间存在一些偏移。

到目前为止，我无法弄清楚这一点。最有可能的是，我错过了一个我现在还不知道的详细信息。我在横向布局上使用ipad 2模拟器。

- (void)viewDidLoad {
    [super viewDidLoad];
    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapGesture:)];
    tapGesture.numberOfTapsRequired = 2;
    [self.imvPhoto addGestureRecognizer:tapGesture];
    tapGesture.delegate = self;
}
 - (void)handleTapGesture:(UITapGestureRecognizer *)sender {
    if (sender.state == UIGestureRecognizerStateRecognized) {
        // handling code

        CGPoint point = [sender locationInView:sender.view];
        NSLog(@"Coordinates are %f, %f", point.x, point.y);
        UIImage* anno=[UIImage imageNamed:@"annotation_icon.png"];

        imvPhoto.image = [self drawImage:anno inImage:imvPhoto.image atPoint:point];

    }
}

-(UIImage*) drawImage:(UIImage*) fgImage
              inImage:(UIImage*) bgImage
              atPoint:(CGPoint)  point
{
    UIGraphicsBeginImageContextWithOptions(bgImage.size, FALSE, 0.0);
    [bgImage drawInRect:CGRectMake( 0, 0, bgImage.size.width, bgImage.size.height)];
    [fgImage drawInRect:CGRectMake((point.x - fgImage.size.width/2), (point.y - fgImage.size.height/2), fgImage.size.width, fgImage.size.height)];

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newImage;
}

Answer 1

您必须更改以下代码：

[fgImage drawInRect:CGRectMake(point.x, point.y, fgImage.size.width, fgImage.size.height)];

到

[fgImage drawInRect:CGRectMake((point.x - fgImage.size.width/2), (point.y - fgImage.size.height/2), fgImage.size.width, fgImage.size.height)];

Answer 2

问题是我的背景图片大小是832乘603，我不知道。一旦图像被加载，它就会扩展到全屏，我认为它是1024 * 768。一旦我修正了图像的大小，问题就解决了。

iOS中的触动点

2 个答案: