Convertir l'image en problème B & W CGContext – iPhone Dev

J'utilise une méthode pour convertir les images sockets avec l'appareil photo en noir et blanc. Le problème que je rencontre est que si l'image est prise en mode portrait, elle tourne et s'étire dans la vue suivante. Mais, si l'on prend en paysage c'est juste find.

Je peux seulement reproduire ce bogue quand je convertis l'image en noir et blanc. Voici la méthode que j'utilise.

Je ne suis pas 100% que ce bug provient de la conversion, mais cela n'arrive que lorsqu'il est converti. Oh ouais. C'est l'iOS 4.

/// - (UIImage *)convertImageToGrayScale:(UIImage *)image { // Create image rectangle with current image width/height CGRect imageRect = CGRectMake(0, 0, image.size.width, image.size.height); // Grayscale color space CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray(); // Create bitmap content with current image size and grayscale colorspace CGContextRef context = CGBitmapContextCreate(nil, image.size.width, image.size.height, 8, 0, colorSpace, kCGImageAlphaNone); // Draw image into current context, with specified rectangle // using previously defined context (with grayscale colorspace) CGContextDrawImage(context, imageRect, [image CGImage]); // Create bitmap image info from pixel data in current context CGImageRef imageRef = CGBitmapContextCreateImage(context); // Create a new UIImage object UIImage *newImage = [UIImage imageWithCGImage:imageRef]; // Release colorspace, context and bitmap information CGColorSpaceRelease(colorSpace); CGContextRelease(context); CFRelease(imageRef); // Return the new grayscale image return newImage; }

@lessfame

Je l'ai eu.

Ce que j'ai fini par faire est de find cette fonction qui fait tourner les images en fonction de la transformation en fonction de l'orientation. Ce qu'il fait est corrige ce bug de rotation bizarre.

Heres l'extrait de code:

 - (UIImage *)rotateImage:(UIImage *)image { int kMaxResolution = 320; // Or whatever CGImageRef imgRef = image.CGImage; CGFloat width = CGImageGetWidth(imgRef); CGFloat height = CGImageGetHeight(imgRef); CGAffineTransform transform = CGAffineTransformIdentity; CGRect bounds = CGRectMake(0, 0, width, height); if (width > kMaxResolution || height > kMaxResolution) { CGFloat ratio = width/height; if (ratio > 1) { bounds.size.width = kMaxResolution; bounds.size.height = bounds.size.width / ratio; } else { bounds.size.height = kMaxResolution; bounds.size.width = bounds.size.height * ratio; } } CGFloat scaleRatio = bounds.size.width / width; CGSize imageSize = CGSizeMake(CGImageGetWidth(imgRef), CGImageGetHeight(imgRef)); CGFloat boundHeight; UIImageOrientation orient = image.imageOrientation; switch(orient) { case UIImageOrientationUp: //EXIF = 1 transform = CGAffineTransformIdentity; break; case UIImageOrientationUpMirrored: //EXIF = 2 transform = CGAffineTransformMakeTranslation(imageSize.width, 0.0); transform = CGAffineTransformScale(transform, -1.0, 1.0); break; case UIImageOrientationDown: //EXIF = 3 transform = CGAffineTransformMakeTranslation(imageSize.width, imageSize.height); transform = CGAffineTransformRotate(transform, M_PI); break; case UIImageOrientationDownMirrored: //EXIF = 4 transform = CGAffineTransformMakeTranslation(0.0, imageSize.height); transform = CGAffineTransformScale(transform, 1.0, -1.0); break; case UIImageOrientationLeftMirrored: //EXIF = 5 boundHeight = bounds.size.height; bounds.size.height = bounds.size.width; bounds.size.width = boundHeight; transform = CGAffineTransformMakeTranslation(imageSize.height, imageSize.width); transform = CGAffineTransformScale(transform, -1.0, 1.0); transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0); break; case UIImageOrientationLeft: //EXIF = 6 boundHeight = bounds.size.height; bounds.size.height = bounds.size.width; bounds.size.width = boundHeight; transform = CGAffineTransformMakeTranslation(0.0, imageSize.width); transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0); break; case UIImageOrientationRightMirrored: //EXIF = 7 boundHeight = bounds.size.height; bounds.size.height = bounds.size.width; bounds.size.width = boundHeight; transform = CGAffineTransformMakeScale(-1.0, 1.0); transform = CGAffineTransformRotate(transform, M_PI / 2.0); break; case UIImageOrientationRight: //EXIF = 8 boundHeight = bounds.size.height; bounds.size.height = bounds.size.width; bounds.size.width = boundHeight; transform = CGAffineTransformMakeTranslation(imageSize.height, 0.0); transform = CGAffineTransformRotate(transform, M_PI / 2.0); break; default: [NSException raise:NSInternalInconsistencyException format:@"Invalid image orientation"]; } UIGraphicsBeginImageContext(bounds.size); CGContextRef context = UIGraphicsGetCurrentContext(); if (orient == UIImageOrientationRight || orient == UIImageOrientationLeft) { CGContextScaleCTM(context, -scaleRatio, scaleRatio); CGContextTranslateCTM(context, -height, 0); } else { CGContextScaleCTM(context, scaleRatio, -scaleRatio); CGContextTranslateCTM(context, 0, -height); } CGContextConcatCTM(context, transform); CGContextDrawImage(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, width, height), imgRef); UIImage *imageCopy = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return imageCopy; }

La méthode returnne une IMAGE que je peux ensuite utiliser dans ma fonction BLACK AND WHITE

 - (UIImage *)convertImageToGrayScale:(UIImage *)image { image = [self rotateImage:image];//THIS IS WHERE REPAIR THE ROTATION PROBLEM // Create image rectangle with current image width/height CGRect imageRect = CGRectMake(0, 0, image.size.width, image.size.height); // Grayscale color space CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray(); // Create bitmap content with current image size and grayscale colorspace CGContextRef context = CGBitmapContextCreate(nil, image.size.width, image.size.height, 8, 0, colorSpace, kCGImageAlphaNone); // Draw image into current context, with specified rectangle // using previously defined context (with grayscale colorspace) CGContextDrawImage(context, imageRect, [image CGImage]); // Create bitmap image info from pixel data in current context CGImageRef imageRef = CGBitmapContextCreateImage(context); // Create a new UIImage object UIImage *newImage = [UIImage imageWithCGImage:imageRef]; // Release colorspace, context and bitmap information CGColorSpaceRelease(colorSpace); CGContextRelease(context); CFRelease(imageRef); // Return the new grayscale image return newImage; }

PRENDRE PLAISIR!

J'ai modifié pour pouvoir traiter des images à l'échelle 2.0 sans perte de résolution:

 - (UIImage *)convertImageToGrayScale:(UIImage *)image { // Create image rectangle with current image width/height CGRect imageRect = CGRectMake(0, 0, image.scale*image.size.width, image.scale*image.size.height); // Grayscale color space CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray(); // Create bitmap content with current image size and grayscale colorspace CGContextRef context = CGBitmapContextCreate(nil, image.scale*image.size.width, image.scale*image.size.height, 8, 0, colorSpace, kCGImageAlphaNone); // Draw image into current context, with specified rectangle // using previously defined context (with grayscale colorspace) CGContextDrawImage(context, imageRect, [image CGImage]); // Create bitmap image info from pixel data in current context CGImageRef imageRef = CGBitmapContextCreateImage(context); // Create a new UIImage object UIImage *newImage = [UIImage imageWithCGImage:imageRef scale:image.scale orientation:image.imageOrientation]; // Release colorspace, context and bitmap information CGColorSpaceRelease(colorSpace); CGContextRelease(context); CFRelease(imageRef); // Return the new grayscale image return newImage; }

Je pense que j'ai compris ça. Aller tester maintenant.

Il s'avère qu'il existe des indicateurs d'orientation UIImage. J'ai trouvé un fil de soutien à: http://discussions.apple.com/message.jspa?messageID=7276709

Mon sharepoint vue est d'utiliser un interrupteur pour vérifier l'orientation, et en partant de celui-ci, faites-le tourner dans son orientation correcte.

Je post le code après que je l'ai compris.

Stanks!

@lessfame