UIImagePickerController 编辑视图圆叠加 [英] UIImagePickerController editing view circle overlay

问题描述

我已经能够完成我一直想要完成的工作，那就是复制 iOS 的内置圆形照片裁剪器，用于内置联系人应用程序.但是，我一直在努力使我的 CAShapeLayers 正确制作.我正在尝试制作一个直径为 320 像素的透明圆，而视图的其余部分则填充了 0.9 alpha 黑色背景.圆形和矩形位于正确的位置，但是，圆形并不像我需要的那样完全透明.

I've been able to get pretty far with what I've been wanting to accomplish, and that's to replicate iOS's built in circular photo cropper for the built in contacts app. However, I'm stuck at trying to get my CAShapeLayers made correctly. I'm trying to make a transparent 320 px diameter circle and the rest of the view filled with an 0.9 alpha black background. The circle and rectangle are in the right place, but, the circle is not completely transparent like I need it to be.

我不知道如何解决这个问题.我感谢您的帮助！代码和截图:

I'm lost as to how to fix this. I appreciate your help! Code and screenshot:

- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    if ([navigationController.viewControllers count] == 3)
    {
        CGRect screenRect = [[UIScreen mainScreen] bounds];
        CGFloat screenHeight = screenRect.size.height;

        UIView *plCropOverlay = [[[viewController.view.subviews objectAtIndex:1]subviews] objectAtIndex:0];

        plCropOverlay.hidden = YES;

        CAShapeLayer *circleLayer = [CAShapeLayer layer];

        if (screenHeight == 568)
        {
            [circleLayer setPosition:CGPointMake(0.0f,124.0f)];
        }    
        else
        {
            [circleLayer setPosition:CGPointMake(0.0f,80.0f)];
        }

        UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:
                          CGRectMake(0.0f, 0.0f, 320.0f, 320.0f)];

        [circleLayer setPath:[path CGPath]];

        [circleLayer setFillColor:[[UIColor whiteColor] CGColor]];
        circleLayer.opacity = 0.7f;

        // Set to 0.7f to show for screenshot purposes; setting to 0.0 would make it invisible and blend in with the below rectangleLayer.

        CAShapeLayer *rectangleLayer = [CAShapeLayer layer];

        UIBezierPath *path2 = [UIBezierPath bezierPathWithRect:CGRectMake(0.0f, 0.0f, 320.0f, screenHeight - 72)];
        [rectangleLayer setPath:[path2 CGPath]];

        [rectangleLayer setFillColor:[[UIColor blackColor] CGColor]];
        [rectangleLayer setOpacity:0.9f];
        [rectangleLayer addSublayer:circleLayer];
        [[viewController.view layer] addSublayer:rectangleLayer];

        UILabel *moveLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, 10, 320, 50)];
        [moveLabel setText:@"Move and Scale"];
        [moveLabel setTextAlignment:NSTextAlignmentCenter];
        [moveLabel setTextColor:[UIColor whiteColor]];

        [viewController.view addSubview:moveLabel];
    }
}

推荐答案

解决代码:

- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    if ([navigationController.viewControllers count] == 3)
    {
        CGFloat screenHeight = [[UIScreen mainScreen] bounds].size.height;

        UIView *plCropOverlay = [[[viewController.view.subviews objectAtIndex:1]subviews] objectAtIndex:0];

        plCropOverlay.hidden = YES;

        int position = 0;

        if (screenHeight == 568)
        {
            position = 124;
        }
        else
        {
            position = 80;
        }

        CAShapeLayer *circleLayer = [CAShapeLayer layer];

        UIBezierPath *path2 = [UIBezierPath bezierPathWithOvalInRect:
                           CGRectMake(0.0f, position, 320.0f, 320.0f)];
        [path2 setUsesEvenOddFillRule:YES];

        [circleLayer setPath:[path2 CGPath]];

        [circleLayer setFillColor:[[UIColor clearColor] CGColor]];
        UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, 320, screenHeight-72) cornerRadius:0];

        [path appendPath:path2];
        [path setUsesEvenOddFillRule:YES];

        CAShapeLayer *fillLayer = [CAShapeLayer layer];
        fillLayer.path = path.CGPath;
        fillLayer.fillRule = kCAFillRuleEvenOdd;
        fillLayer.fillColor = [UIColor blackColor].CGColor;
        fillLayer.opacity = 0.8;
        [viewController.view.layer addSublayer:fillLayer];

        UILabel *moveLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, 10, 320, 50)];
        [moveLabel setText:@"Move and Scale"];
        [moveLabel setTextAlignment:NSTextAlignmentCenter];
        [moveLabel setTextColor:[UIColor whiteColor]];

        [viewController.view addSubview:moveLabel];
    }
}

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