Question

我有以下代码，我大部分来自SO，但我的图像仍然没有被裁剪，我做错了什么？

@synthesize TopImage;
@synthesize BottomImage;
@synthesize RotaterImage;

- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
    TopImage = [UIImage imageNamed:@"zero.png"];
    [TopImage drawAtPoint:CGPointMake(0, 0)];
    [self cropImage:TopImage:0];
    [self addSubview:[[UIImageView alloc] initWithImage:TopImage]];
//        BottomImage = [UIImage imageNamed:@"zero.png"];
//        [BottomImage drawAtPoint:CGPointMake(0, 55)];
//        [self cropImage:BottomImage:50];
//        [self addSubview:[[[UIImageView alloc] initWithImage:BottomImage]retain]];
//        RotaterImage = [UIImage imageNamed:@"zero.png"];
//        [RotaterImage drawAtPoint:CGPointMake(0, 0) blendMode:kCGBlendModeNormal alpha:0];
//        [self addSubview:[[[UIImageView alloc] initWithImage:RotaterImage]retain]];
//        [self cropImage:RotaterImage:50];
    }
    return self;
}

-(void)cropImage:(UIImage *)image:(int)startCroppingPosition{
  CGRect tempRect = CGRectMake(0, startCroppingPosition, 23, 40);
  CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], tempRect);
  // or use the UIImage wherever you like
  image = [UIImage imageWithCGImage:imageRef]; 
  CGImageRelease(imageRef);
}

我对IOS很新，所以感谢任何帮助

Answer 1

您正在创建新的裁剪图片，但没有告诉init方法：）

尝试此更改：

-(UIImage *)cropImage:(UIImage *)image:(int)startCroppingPosition{
  CGRect tempRect = CGRectMake(0, startCroppingPosition, 23, 40);
  CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], tempRect);
  // or use the UIImage wherever you like
  UIImage *newImage = [UIImage imageWithCGImage:imageRef]; 
  CGImageRelease(imageRef);
  return newImage;
}

，在init中，替换

[TopImage drawAtPoint:CGPointMake(0, 0)];

与

UIImageView* topImageView = [[UIImageView alloc] initWithImage:topImage];
topImageView.frame = CGRectMake(x,y,width,height);

您的裁剪方法现在返回新裁剪的图像，并将其存储在TopImage。

中

其他建议：

类名以CapitalLetter开头，变量以小写开头。 TopImage应该是topImage。

另外，我总是在你的方法中使用命名参数，所以

-(void)cropImage:(UIImage *)image:(int)startCroppingPosition

应该是

-(void)cropImage:(UIImage *)image startPosition:(int)startCroppingPosition

当你在一个月的时间内回到它时，这将使你的代码更具可读性（我已经了解了过去的艰难方法！）

Answer 2

您只是更改图像而不是UIImageView的图像，

我要做的是替换：

[self addSubview:[[UIImageView alloc] initWithImage:TopImage]];

带

UIImageView *iv = [[UIImageView alloc] initWithImage:TopImage]];
iv.tag = 1000 //number does not matter 
[self.view addSubview:iv];
[iv release];

然后在裁剪图片中添加：

UIImageView *iv = [self.vief viewWithTag:1000];
iv.image = [UIImage imageWithCGImage:imageRef];

这应该按预期工作！

我的形象没有被裁剪

2 个答案: