Question

css怎么让div的高度随着宽度按比例缩放

Answer 1

css怎么让div的高度随着宽度按比例缩放

常用的方法是通过背景图示的cover属性让div的高度随着宽度按比例缩放

#banner .bd li {
width: 100%;
background-repeat:
no-repeat;
background-size: cover;
background-position: center
0;
background-position: 50% 50%;
-webkit-background-size:
100%;
padding-: 42%;
}
‍

C#怎么让控制元件随窗体按比例缩放？

你可否换个事件写缩放程式码？放到载入里面去

cad家俱怎么按比例缩放

操作步骤如下：
命令: sc
SCALE
选择物件: 指定对角点: 找到 1 个
选择物件:
指定基点:
指定比例因子或 [复制(C)/参照(R)]: 2 (比例）

如何按比例缩放UIImageView

CAXA比例是非常方便的，你可以直接输入号码，你可以输入一个表示式，如取两件事情的长度扩大到5，输入比例因子：5/2，就可以了，这种方法并不特别适合知识这种情况放大系数。

按比例缩放需要用程式来完成，可以参照下面的程式：
@interface HYShowImageView : UIScrollView <UIScrollViewDelegate>
显示影象大图
-(void)showImage:(UIImage*)image inView:(UIView *)parentsView fromRect:(CGRect)rect;
@end
-(void)showImage:(UIImage*)image inView:(UIView *)parentsView fromRect:(CGRect)rect
{
_oldRect = rect;

[self setFrame:CGRectMake(0, 0, PHOTOWIDTH, PHOTOHEIGHT)];
self.showsHorizontalScrollIndicator = NO;
self.showsVerticalScrollIndicator = NO;

UIImageView *showView = [[UIImageView alloc] initWithFrame:_oldRect];
showView.contentMode = UIViewContentModeScaleAspectFit;
[UIView animateWithDuration:0.5f animations:^{
[showView setFrame:CGRectMake(0, 0, PHOTOWIDTH, PHOTOHEIGHT)];
}];

[self setBackgroundColor:color_with_rgba(0, 0, 0, 1)];
[parentsView addSubview:self];

[showView setTag:'show'];
[showView setImage:image]; 这个地方也可以用网路的图片
[self addSubview:showView];

增加两个手势
showView.userInteractionEnabled = YES;
UITapGestureRecognizer* singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleViewTap:)];
[self addGestureRecognizer:singleTap];

UIPinchGestureRecognizer* pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinchView:)];
[self addGestureRecognizer:pinchGesture];
}
增加了两个手势，一个点选取消，一个缩放

移除图片检视检视
-(void)handleSingleViewTap:(UITapGestureRecognizer *)sender
{
[self setZoomScale:1.0 animated:NO];
[UIView animateWithDuration:0.5f animations:^{
UIImageView *showView = (UIImageView *)[self viewWithTag:'show'];
showView.frame = _oldRect;
self.backgroundColor = color_with_rgba(0, 0, 0, 0.0);
} pletion:^(BOOL finished){
[self removeFromSuperview];
}];
}

缩放图片
-(void)handlePinchView:(UIPinchGestureRecognizer *)sender
{
UIImageView *imageView = (UIImageView *)[self viewWithTag:'show'];
if ([sender state] == UIGestureRecognizerStateBegan) {
_imageHWScale = imageView.image.size.height/imageView.image.size.width;
_beganScale = self.zoomScale;
}

[self setZoomScale:_beganScale * sender.scale];

if ([sender state] == UIGestureRecognizerStateEnded) {
[self scrollViewEnd];
}
}

- (void)scrollViewEnd
{
if (self.zoomScale < 1.0) {
[self setZoomScale:1.0 animated:YES];
self.contentOffset = CGPointMake(0, 0);
} else if (self.zoomScale > 3.0) {
[self setZoomScale:3.0 animated:YES];
}
}

把UIImageView放到UIScrollView中，将UIScrollViewDelegate中的- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView方法return这个imageView

js实现div盒子宽度和高度成比例缩放怎么写

说一下思路：

1. 等比例  就是要找出宽高的比。如果100/80

2. 然后在缩放时，先缩放一个，然后用已知的宽高比算另一个值。