ios - 在 UIView 上绘制时 UIImage 反转

Question

我正在使用相机选择器控制器拍照并将其显示在我的应用程序中。但是我不用UIImageView来显示图片。我UIImage在 a 上绘制UIView，我得到的结果是反转的图像。这是屏幕截图：

我点击使用照片后的结果是：

这是我的代码：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

    UIImage *chosenImage = info[UIImagePickerControllerEditedImage];

    dView=[[drawView alloc]initWithFrame:imageUIView.frame];
    [dView drawImage:chosenImage];

    [imageUIView addSubview:dView];

    [picker dismissViewControllerAnimated:YES completion:NULL];

}

在 dView 中：

-(void)drawImage:(UIImage *) imageToDraw{
    self.pic=imageToDraw;
    [imageToDraw drawInRect:self.frame];
    [self setNeedsDisplay];

}

- (void)drawRect:(CGRect)rect {

CGContextRef context = UIGraphicsGetCurrentContext();

CGRect targetBounds = self.layer.bounds;
    // fit the image, preserving its aspect ratio, into our target bounds
CGRect imageRect = AVMakeRectWithAspectRatioInsideRect(self.pic.size,
                                                           targetBounds);
    // draw the image
CGContextDrawImage(context, imageRect, self.pic.CGImage);

// Save the screen to restore next time around
imageRef = CGBitmapContextCreateImage(context);

}

我尝试 正确显示图像，但他们旋转图像，而不是使内容以正确的顺序显示CGAffineTransformMakeRotation。CGContextRotateCTM如您所见，图像中的内容完全颠倒了。

如何在uiimage不改变外观的情况下绘制？

Answer 1

您的drawView班级没有正确绘制图像。尝试这个：

- (void)drawImage:(UIImage *)imageToDraw {
    self.pic = imageToDraw;
    [self setNeedsDisplay];
}

- (void)drawRect:(CGRect)rect {
    CGRect targetBounds = self.layer.bounds;
        // fit the image, preserving its aspect ratio, into our target bounds
    CGRect imageRect = AVMakeRectWithAspectRatioInsideRect(self.pic.size,
                                                               targetBounds);
        // draw the image
    [self.pic drawInRect:imageRect];
}

1. 最好将 a 添加UIImageView为您的drawView. 让图像视图完成正确渲染图像所需的所有工作。
2. 命名约定。类名应该以大写字母开头。变量和方法名称以小写字母开头。