objective-c - UIImageView 模糊图像

Question

我对 UIImageView 有一个非常奇怪的问题。我有一个图像(RGB png)45x45 像素，我将其添加到 View 中。我可以看到图像在添加到 View 后变得模糊。这是模拟器(左)和 Xcode(右)中的相同图像:

_{(来源:partywithvika.com)}

_{(来源:partywithvika.com)}

我有自定义 UIImageView 类和这个 initWithImage 代码:

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

    self.frame = CGRectMake(0, 0, 45, 45);
    self.contentMode = UIViewContentModeScaleAspectFit;

    self.quantity = 1;
    if (self) {
        self.label = [[UITextField alloc]initWithFrame:CGRectMake(0,40,45,25)];
        self.label.font = [UIFont systemFontOfSize:16];
        self.label.borderStyle = UITextBorderStyleNone;
        self.label.enabled = TRUE;
        self.label.userInteractionEnabled = TRUE;
        self.label.delegate = self;
        self.label.keyboardType = UIKeyboardTypeNumbersAndPunctuation;
        self.label.textAlignment = UITextAlignmentCenter;
    }
    self.userInteractionEnabled = TRUE;

    // Prepare 3 buttons: count up, count down, and delete
    self.deleteButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    self.deleteButton.hidden = NO;
    self.deleteButton.userInteractionEnabled = YES;
    self.deleteButton.titleLabel.font  = [UIFont systemFontOfSize:20];
    self.deleteButton.titleLabel.textColor = [UIColor redColor];
    [self.deleteButton setTitle:@"X" forState:UIControlStateNormal];
    [self.deleteButton addTarget:self action:@selector(deleteIcon:) forControlEvents:UIControlEventTouchUpInside];

    self.upCountButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    self.upCountButton.hidden = NO;
    self.upCountButton.userInteractionEnabled = YES;
    [self.upCountButton setTitle:@"+" forState:UIControlStateNormal];
    [self.upCountButton addTarget:self action:@selector(addQuantity:) forControlEvents:UIControlEventTouchUpInside];

    self.downCountButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    self.downCountButton.hidden = YES;
    self.downCountButton.userInteractionEnabled = YES;
    [self.downCountButton setTitle:@"-" forState:UIControlStateNormal];
    [self.downCountButton addTarget:self action:@selector(removeQuantity:) forControlEvents:UIControlEventTouchUpInside];
    return self;
}

我是这样创建的:

UIImage *desertIcon = [UIImage imageNamed:@"desert.png"];
IconObj *desertIconView = [[IconObj alloc] initWithImage:desertIcon];
desertIconView.center = CGPointMake(265,VERTICAL_POINT_ICON);
desertIconView.type = [IconObj TYPE_DESERT];
[self.view addSubview:desertIconView];
[desertIconView release];

为什么显示出来的图片和保存在文件里的图片不一样？

Answer 1

一般来说，您在 iPhone 上使用 UIKit 所做的一切都应该是像素对齐的。像素对齐问题通常表现为模糊(文本和图像尤其是)。这就是为什么当我发现模糊 View 时，我首先检查我是否正在设置 center 属性。当您设置 center 时，框架的 x、y、高度和宽度会围绕该中心点进行调整...经常会产生小数值。

您可以尝试在框架上使用 CGRectIntegral，如下所示:

desertIconView.center = CGPointMake(265,VERTICAL_POINT_ICON);
desertIconView.frame = CGRectIntegral(desertIconView.frame);

这可能有效，但如果无效，请尝试手动设置 frame，而不使用 center 属性以确保没有值是小数。

编辑:糟糕!没有注意到 OP 已经回答了他自己的问题......无论如何我会出于信息原因将其保留。