如何在iPhone中放大图像的选定区域？

Question

单击该图像时我有一个ImageView，应该创建透明圆圈，再次双击该圆圈时，该圆圈区域中的特定图像应该被缩放。任何建议都将受到赞赏。

Answer 1

我认为此代码对您有所帮助

- (id)initWithImage:(UIImage *)image {
    self = [super initWithImage:image];
    if (self) {
        [self setUserInteractionEnabled:YES];

        UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleTap:)];
        UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleTap:)];
        UITapGestureRecognizer *twoFingerTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTwoFingerTap:)];

        [doubleTap setNumberOfTapsRequired:2];
        [twoFingerTap setNumberOfTouchesRequired:2];

        [self addGestureRecognizer:singleTap];
        [self addGestureRecognizer:doubleTap];
        [self addGestureRecognizer:twoFingerTap];

        [singleTap release];
        [doubleTap release];
        [twoFingerTap release];
    }
    return self;
}

#pragma mark Private

- (void)handleSingleTap:(UIGestureRecognizer *)gestureRecognizer {
    if ([delegate respondsToSelector:@selector(tapDetectingImageView:gotSingleTapAtPoint:)])
        [delegate tapDetectingImageView:self gotSingleTapAtPoint:[gestureRecognizer locationInView:self]];
}

- (void)handleDoubleTap:(UIGestureRecognizer *)gestureRecognizer {
    if ([delegate respondsToSelector:@selector(tapDetectingImageView:gotDoubleTapAtPoint:)])
        [delegate tapDetectingImageView:self gotDoubleTapAtPoint:[gestureRecognizer locationInView:self]];
}

- (void)handleTwoFingerTap:(UIGestureRecognizer *)gestureRecognizer {
    if ([delegate respondsToSelector:@selector(tapDetectingImageView:gotTwoFingerTapAtPoint:)])
        [delegate tapDetectingImageView:self gotTwoFingerTapAtPoint:[gestureRecognizer locationInView:self]];
}