在UIView上绘制时，UIImage是相反的

Question

我正在使用相机选择器控制器来拍照并在我的应用中显示它。但是我没有使用UIImageView来显示图片。我在UIImage上绘制UIView，我得到的结果是反转图像。这是截图：

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];

}

并在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CGAffineTransformMakeRotation和CGContextRotateCTM正确显示图像，但是它们会旋转图像，而不是按正确的顺序显示内容。如您所见，图像中的内容完全相反。

如何绘制uiimage而不对其外观进行任何更改？

Answer 1

您的drawView课程未正确绘制图像。试试这个：

- (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. 最好添加UIImageView作为drawView的子视图。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。