如何根据视图图层的颜色更改状态栏颜色

Question

I have an app that uses AVCaptureSession to capture image on the camera to the view's layer. Now I want the status bar to change to white color when the color on top of the image is a dark color just to optimize the user experience. I am thinking of getting the color from a specific pixel and test for the color of that pixel, then I think it is not a good idea because maybe only that pixel could be a different color. So what is the best way to change the status bar color according to what is the color on the top of the image?

Answer 1

Check you view color and set status bar color according view and for change status bar color use below step Goto your app info.plist

1) Set View controller-based status bar appearance to NO

2) Set Status bar style to UIStatusBarStyleLightContent

Then set use below code

 UIView *topView=[[UIView alloc] initWithFrame:CGRectMake(0, 0,[UIScreen mainScreen].bounds.size.width, 20)];
 topView.backgroundColor=[UIColor blackColor];
[self.window.rootViewController.view addSubview:topView];

Answer 2

When I had this kind of problem last -- putting visible text on top of an arbitrary picture -- the most efficient+correct enough way we found to define a region's color was just scaling it to one pixel and seeing what color that was. Might be a better way now, but this worked well enough we never got any complaints, should be reasonably straightforwardly adaptable to whatever image data buffer format you've got handy:

+ (UIColor *)adaptiveColorWithBackgroundImage:(UIImage *)image forRegion:(CGRect)region
{
    region = CGRectMake(region.origin.x * image.scale,
                      region.origin.y * image.scale,
                      region.size.width * image.scale,
                      region.size.height * image.scale);

    CGImageRef imageRef = CGImageCreateWithImageInRect(image.CGImage, region);
    UIImage *croppedImage = [UIImage imageWithCGImage:imageRef scale:image.scale orientation:image.imageOrientation];
    CGImageRelease(imageRef);

    return [UIColor adaptiveColorWithBackgroundImage:croppedImage];
}

+ (UIColor *)adaptiveColorWithBackgroundImage:(UIImage *)image
{
   unsigned char rgb[4] = { 0 };

   // trust scaling to come up with best colored pixel
   CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
   CGContextRef bitmap = CGBitmapContextCreate(rgb,1,1,8,4,colorSpace,kCGImageAlphaNoneSkipLast);
    CGColorSpaceRelease(colorSpace);
   CGContextSetInterpolationQuality(bitmap, kCGInterpolationHigh);
   CGContextDrawImage(bitmap, CGRectMake(0,0,1,1), image.CGImage);
   CGContextRelease(bitmap);

   UIColor *imageColor = [UIColor colorWithRed:rgb[0]/255.f green:rgb[1]/255.f blue:rgb[2]/255.f alpha:1];
   UIColor *adaptiveColor = [UIColor adaptiveColorWithBackgroundColor:imageColor];

   return adaptiveColor;
}

+ (UIColor *)adaptiveColorWithBackgroundColor:(UIColor *)bkg
{
    CGFloat grayComponent = 0.5; //  this will default to dark text

    CGColorSpaceRef colorSpace = CGColorGetColorSpace(bkg.CGColor);
    CGColorSpaceModel colorSpaceModel = CGColorSpaceGetModel(colorSpace);

    switch (colorSpaceModel)
    {
        case kCGColorSpaceModelLab:
        {
            // Fallthrough... treat the Luminance component the same as grayscale
        }
        case kCGColorSpaceModelMonochrome:
        {
            const CGFloat *components = CGColorGetComponents(bkg.CGColor);
            grayComponent = components[0];
            break;
        }   
        case kCGColorSpaceModelRGB: // convert to grayscale
        {
            const CGFloat *components = CGColorGetComponents(bkg.CGColor);
            grayComponent = (components[0] * 0.3f) + (components[1] * 0.59f) + (components[2] * 0.11f);
            break;
        }
        case kCGColorSpaceModelPattern:
        {
            unsigned char rgb[4] = { 0 };

            // trust scaling to come up with best colored pixel
            CGColorSpaceRef colorSpace1 = CGColorSpaceCreateDeviceRGB();
            CGContextRef bitmap = CGBitmapContextCreate(rgb,1,1,8,4,colorSpace1,kCGImageAlphaNoneSkipLast);
            CGColorSpaceRelease(colorSpace1);
            CGContextSetInterpolationQuality(bitmap, kCGInterpolationHigh);

            CGContextSetFillColorWithColor(bitmap, [bkg CGColor]);
            CGContextFillRect(bitmap, CGRectMake(0,0,1,1));

            CGContextRelease(bitmap);

            grayComponent = (rgb[0]/255.0f * 0.3f) + (rgb[1]/255.0f * 0.59f) + (rgb[2]/255.0f * 0.11f);
            break;
        }
        default:
        {
            // unsuported colorspace return default
            break;
        }
    } 

    // dark background defined as greater than 60% gray
    // slightly biased towards white
    return (grayComponent <= 0.6) ? UIColor.whiteColor : UIColor.blackColor;   
}