Hard crash when drawing content for CALayer using quartz
- by Lukasz
I am trying to figure out why iOS crash my application in the harsh way (no crash logs, immediate shudown with black screen of death with spinner shown for a while).
It happens when I render content for CALayer using Quartz. I suspected the memory issue (happens only when testing on the device), but memory logs, as well as instruments allocation logs looks quite OK. Let me past in the fatal function:
- (void)renderTiles{
if (rendering) {
//NSLog(@"====== RENDERING TILES SKIP =======");
return;
}
rendering = YES;
CGRect b = tileLayer.bounds;
CGSize s = b.size;
CGFloat imageScale = [[UIScreen mainScreen] scale];
s.height *= imageScale;
s.width *= imageScale;
dispatch_async(queue, ^{
NSLog(@"");
NSLog(@"====== RENDERING TILES START =======");
NSLog(@"1. Before creating context");
report_memory();
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
NSLog(@"2. After creating color space");
report_memory();
NSLog(@"3. About to create context with size: %@", NSStringFromCGSize(s));
CGContextRef ctx = CGBitmapContextCreate(NULL, s.width, s.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast);
NSLog(@"4. After creating context");
report_memory();
CGAffineTransform flipTransform = CGAffineTransformMake(1.0, 0.0, 0.0, -1.0, 0.0, s.height);
CGContextConcatCTM(ctx, flipTransform);
CGRect tileRect = CGRectMake(0, 0, tileImageScaledSize.width, tileImageScaledSize.height);
CGContextDrawTiledImage(ctx, tileRect, tileCGImageScaled);
NSLog(@"5. Before creating cgimage from context");
report_memory();
CGImageRef cgImage = CGBitmapContextCreateImage(ctx);
NSLog(@"6. After creating cgimage from context");
report_memory();
dispatch_sync(dispatch_get_main_queue(), ^{
tileLayer.contents = (id)cgImage;
});
NSLog(@"7. After asgning tile layer contents = cgimage");
report_memory();
CGColorSpaceRelease(colorSpace);
CGContextRelease(ctx);
CGImageRelease(cgImage);
NSLog(@"8. After releasing image and context context");
report_memory();
NSLog(@"====== RENDERING TILES END =======");
NSLog(@"");
rendering = NO;
});
}
Here are the logs:
====== RENDERING TILES START =======
1. Before creating context
Memory in use (in bytes): 28340224 / 519442432 (5.5%)
2. After creating color space
Memory in use (in bytes): 28340224 / 519442432 (5.5%)
3. About to create context with size: {6324, 5208}
4. After creating context
Memory in use (in bytes): 28344320 / 651268096 (4.4%)
5. Before creating cgimage from context
Memory in use (in bytes): 153649152 / 651333632 (23.6%)
6. After creating cgimage from context
Memory in use (in bytes): 153649152 / 783159296 (19.6%)
7. After asgning tile layer contents = cgimage
Memory in use (in bytes): 153653248 / 783253504 (19.6%)
8. After releasing image and context context
Memory in use (in bytes): 21688320 / 651288576 (3.3%)
====== RENDERING TILES END =======
Application crashes in random places. Sometimes when reaching en of the function and sometime in random step.
Which direction should I look for a solution? Is is possible that GDC is causing the problem? Or maybe the context size or some Core Animation underlying references?
