实例017 旋转和缩放视图

实例说明

本实例的功能是，使用UIView的属性transform来翻转或者放缩视图。首先在屏幕上方设置了UIImageView区域，在此区域显示一幅图片。在下方设置了4个按钮，分别是旋转、扩大、缩小、反转，这4个按钮对应如下所示的4个方法。

- (void)rotateDidPush：以90度为单位旋转。

- (void)bigDidPush：以0.1为单位扩大。

- (void)smallDidPush：以0.1为单位缩小。

- (void)invertDidPush：左右反转。

具体实现

实例文件UIkitPrjTransform.h的实现代码如下所示。

#import "SampleBaseController.h"
@interface UIKitPrjTransform : SampleBaseController
{
 @private
  UIImageView* imageView_;
  CGFloat rotate_;
  CGFloat scale_;
  bool   needFlip_;
}
@end

实例文件UIkitPrjTransform.m的实现代码如下所示。

#import "UIKitPrjTransform.h"
#pragma mark ----- Private Methods Definition -----
@interface UIKitPrjTransform ()
- (void)rotateDidPush;
- (void)bigDidPush;
- (void)smallDidPush;
- (void)invertDidPush;
- (void)transformWithAnimation;
@end
#pragma mark ----- Start Implementation For Methods -----
@implementation UIKitPrjTransform
// finalize
- (void)dealloc {
  [imageView_ release];
  [super dealloc];
}
- (void)viewDidLoad {
  [super viewDidLoad];
  rotate_ = 0.0;
  scale_ = 1.0;
  needFlip_ = NO;
  // 背景设为黑
  self.view.backgroundColor = [UIColor blackColor];
  // 追加图像View
  NSString*  path  =  [NSString  stringWithFormat:@"%@/%@",  [[NSBundle  mainBundle]
resourcePath], @"dog.jpg"];
  UIImage* image = [[[UIImage alloc] initWithContentsOfFile:path] autorelease];
  imageView_ = [[UIImageView alloc] initWithImage:image];
  CGPoint newPoint = self.view.center;
  newPoint.y = self.view.center.y -60;
  imageView_.center = newPoint;
  [self.view addSubview:imageView_];
  // 追加“旋转”按钮
  UIButton* rotateButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
  rotateButton.frame = CGRectMake( 0, 0, 50, 40 );
  newPoint = self.view.center;
  newPoint.x -= 75;
  newPoint.y = self.view.frame.size.height -70;
  rotateButton.center = newPoint;
  [rotateButton setTitle:@"旋转" forState:UIControlStateNormal];
  [rotateButton addTarget:self
              action:@selector(rotateDidPush)
      forControlEvents:UIControlEventTouchUpInside];
  // 追加“扩大”按钮
  UIButton* bigButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
  bigButton.frame = rotateButton.frame;
  newPoint.x += 50;
  bigButton.center = newPoint;
  [bigButton setTitle:@"扩大" forState:UIControlStateNormal];
  [bigButton addTarget:self
              action:@selector(bigDidPush)
      forControlEvents:UIControlEventTouchUpInside];
  // 追加“缩小”按钮
  UIButton* smallButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
  smallButton.frame = rotateButton.frame;
  newPoint.x += 50;
  smallButton.center = newPoint;
  [smallButton setTitle:@"缩小" forState:UIControlStateNormal];
  [smallButton addTarget:self
              action:@selector(smallDidPush)
      forControlEvents:UIControlEventTouchUpInside];
  // 追加“反转”按钮
  UIButton* invertButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
  invertButton.frame = rotateButton.frame;
  newPoint.x += 50;
  invertButton.center = newPoint;
  [invertButton setTitle:@"反转" forState:UIControlStateNormal];
  [invertButton addTarget:self
              action:@selector(invertDidPush)
      forControlEvents:UIControlEventTouchUpInside];
  [self.view addSubview:rotateButton];
  [self.view addSubview:bigButton];
  [self.view addSubview:smallButton];
  [self.view addSubview:invertButton];
}
#pragma mark ----- Private Methods -----
- (void)rotateDidPush {
  // 以90度为单位旋转
  rotate_ += 90.0;
  if ( 359.0 < rotate_ ) {
      rotate_ = 0.0;
  }
  [self transformWithAnimation];
}
- (void)bigDidPush {
  // 以0.1为单位扩大
  scale_ += 0.1;
  [self transformWithAnimation];
}
- (void)smallDidPush {
  // 以0.1为单位缩小
  scale_ -= 0.1;
  [self transformWithAnimation];
}
- (void)invertDidPush {
  // 左右反转
  needFlip_ = ! needFlip_;
  [self transformWithAnimation];
}
- (void)transformWithAnimation {
  [UIView beginAnimations:nil context:NULL];
  CGAffineTransform transformRotate =
    CGAffineTransformMakeRotation( rotate_ * ( M_PI / 180.0 ) );
  CGAffineTransform transformScale =
    CGAffineTransformMakeScale( scale_, scale_ );
  CGAffineTransform transformAll =
    CGAffineTransformConcat( transformRotate, transformScale );
  if ( needFlip_ ) {
    transformAll = CGAffineTransformScale( transformAll, -1.0, 1.0 );
  }
  imageView_.transform = transformAll;
  [UIView commitAnimations];
}
- (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event {
  [self.navigationController setNavigationBarHidden:NO animated:YES];
}
@end

执行后的效果如图2-21所示。

图2-21 执行效果