CODEWITHSUNDEEP
iphoneiosobjective-cxcode
user1354603
user1354603

Reputation: 4034

CGContextSaveGState invalid context

I am developing an iOS-application which uses a live camera feed to scan for bar- and qr-codes. However sometimes I get errors.. these errors do not crash the application, but it might be a good idea to fix them. These are the errors:

<Error>: CGContextSaveGState: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextSetBlendMode: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextSetAlpha: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextTranslateCTM: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextScaleCTM: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextDrawImage: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextRestoreGState: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextSetInterpolationQuality: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextSetAllowsAntialiasing: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextTranslateCTM: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextScaleCTM: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextFlush: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGBitmapContextCreateImage: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextSetInterpolationQuality: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextSetAllowsAntialiasing: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextTranslateCTM: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextScaleCTM: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGContextFlush: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
<Error>: CGBitmapContextCreateImage: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context  and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.

And I believe this code is responsible for the errors message:

- (UIImage *)cropImage:(UIImage *)oldImage sideCrop:(float)crop {
CGSize imageSize = oldImage.size;
UIGraphicsBeginImageContextWithOptions( CGSizeMake( imageSize.width - 2*crop,
                                                   imageSize.height ),
                                       NO,
                                       0.);
[oldImage drawAtPoint:CGPointMake( -crop, 0)
            blendMode:kCGBlendModeCopy
                alpha:1.];
UIImage *croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return croppedImage;
}

Upvotes: 26

Views: 29589

Answers (3)

MH175
MH175

Reputation: 2334

In case anyone else is running into this problem, in my case I was incorrectly calling path.stroke() and path.fill() directly on a CAShapeLayer's path. These methods should only be called when you actually have a context (i.e. inside draw(rect:)).

Upvotes: 13

loretoparisi
loretoparisi

Reputation: 16281

I get this error when doing like

UIGraphicsBeginImageContextWithOptions(gradientLayer.bounds.size,
                                           NO,
                                           1.0f);
    [gradientLayer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *gradientColorImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

where

(lldb) po gradientLayer.bounds
(origin = (x = 0, y = 0), size = (width = 0, height = 0))
(origin = (x = 0, y = 0), size = (width = 0, height = 0))
(lldb) po gradientLayer.bounds.size
(width = 0, height = 0)
(width = 0, height = 0)

so when the width or height of the bounds is zero.

SO I just did a simple width non zero check in my code like

+ (UIImage *)gradientColorImageWithColors:(NSArray *)colorsArray gradientType:(GradientImageType)type andSize:(CGSize)imageSize addingLightEffect:(BOOL)addLightEffect {

if(imageSize.width==0) {
    return nil;
}

I was using this method changing the appearance of the UINavigationBar:

[[UINavigationBar appearanceWhenContainedIn: [UINavigationController class], nil] setBackgroundImage: [UIImage gradientColorImageWithColors:@[(id)COLORS_NAVIGATION_BAR_1.CGColor, (id)COLORS_NAVIGATION_BAR_2.CGColor]
                                                                                                                          gradientType:GradientImageTypeHorizontal
                                                                                                                               andSize:(CGSize){CGRectGetWidth( [UIScreen mainScreen].bounds ), 1.0f}]
                                                                                    forBarMetrics:UIBarMetricsDefault];

Upvotes: 1

graver
graver

Reputation: 15213

The UIGraphicsBeginImageContextWithOptions method is being passed size with either width = 0 and/or height = 0. Debug and resolve the problem.

Upvotes: 63

Related Questions