UIGraphicsGetCurrentContext Problem
I have a problem drawing objects passing this graphic context
CGContextRef context = UIGraphicsGetCurrentContext();
Here is the code I use to draw
- (void) draw: (CGContextRef) gc
{
CGFloat black[4] = {0.0f, 0.0f, 0.0f, 1.0f}; // R G B + Alpha
CGPoint p [2];
p[0].x = xStart ;
p[0].y = yStart ;
p[1].x = xEnd ;
p[1].y = yEnd ;
CGContextSetStrokeColor(gc, black); //Definie la couleur
CGContextStrokeLineSegments(gc, p, 2 ) ;
}
Some object draw, other don't (very strange) and in the console I read:
Thu Mar 24 21:53:59 MacBook-Air-di-Michele-Giarratana.local IVBricker[381] &开发者_开发技巧lt;Error>: CGContextDrawImage: invalid context 0x0
Thu Mar 24 21:53:59 MacBook-Air-di-Michele-Giarratana.local IVBricker[381] <Error>: CGContextSetStrokeColor: invalid context 0x0
Thu Mar 24 21:53:59 MacBook-Air-di-Michele-Giarratana.local IVBricker[381] <Error>: CGContextStrokeLineSegments: invalid context 0x0
Thu Mar 24 21:53:59 MacBook-Air-di-Michele-Giarratana.local IVBricker[381] <Error>: CGContextSetStrokeColor: invalid context 0x0
Thu Mar 24 21:53:59 MacBook-Air-di-Michele-Giarratana.local IVBricker[381] <Error>: CGContextStrokeLineSegments: invalid context 0x0
Thu Mar 24 21:53:59 MacBook-Air-di-Michele-Giarratana.local IVBricker[381] <Error>: CGContextSetStrokeColor: invalid context 0x0
Thu Mar 24 21:53:59 MacBook-Air-di-Michele-Giarratana.local IVBricker[381] <Error>: CGContextStrokeLineSegments: invalid context 0x0
Thu Mar 24 21:53:59 MacBook-Air-di-Michele-Giarratana.local IVBricker[381] <Error>: CGContextSetStrokeColor: invalid context 0x0
Thu Mar 24 21:53:59 MacBook-Air-di-Michele-Giarratana.local IVBricker[381] <Error>: CGContextStrokeLineSegments: invalid context 0x0
Thu Mar 24 21:53:59 MacBook-Air-di-Michele-Giarratana.local IVBricker[381] <Error>: CGContextSetStrokeColor: invalid context 0x0
Thu Mar 24 21:53:59 MacBook-Air-di-Michele-Giarratana.local IVBricker[381] <Error>: CGContextStrokeLineSegments: invalid context 0x0
So I can't speak to the invalid content errors because we'd need to see the rest of the code but it looks like the colour space could be incorrect (it's not RGB by default). Add this before you call stroke:
CGContextSetStrokeColorSpace(gc, CGColorSpaceCreateDeviceRGB());
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