J'utilise ce morceau de code pour mettre à l'échelle et faire pivoter les images prises avec l'appareil photo. Quand je l'utilise, je peux voir un énorme pic de mémoire. Quelque chose comme 20 Mo. Quand j'utilise les instruments, je peux voir que cette ligne:Pic de mémoire énorme - CGContextDrawImage
CGContextDrawImage (ctxt, orig, self.CGImage);
contient 20 Mo. Est-ce normal pour les photos en pleine résolution? L'iPhone 4S peut le gérer. mais les appareils plus anciens se bloque à cause de ce code. Après avoir redimensionné l'image dont j'ai besoin dans NSData, j'utilise la méthode UIImageJPEGRepresentation(). Cela ensemble rend le pic de mémoire encore plus élevé. Il va à 70 Mo en utilisation de la mémoire pendant plusieurs secondes.
Et oui, j'ai lu presque toutes les questions liées à l'appareil photo iOS sur l'utilisation de la mémoire. Mais pas de réponse là-bas.
// WBImage.mm -- extra UIImage methods
// by allen brunson march 29 2009
#include "WBImage.h"
static inline CGFloat degreesToRadians(CGFloat degrees)
{
return M_PI * (degrees/180.0);
}
static inline CGSize swapWidthAndHeight(CGSize size)
{
CGFloat swap = size.width;
size.width = size.height;
size.height = swap;
return size;
}
@implementation UIImage (WBImage)
// rotate an image to any 90-degree orientation, with or without mirroring.
// original code by kevin lohman, heavily modified by yours truly.
// http://blog.logichigh.com/2008/06/05/uiimage-fix/
-(UIImage*)rotate:(UIImageOrientation)orient
{
CGRect bnds = CGRectZero;
UIImage* copy = nil;
CGContextRef ctxt = nil;
CGRect rect = CGRectZero;
CGAffineTransform tran = CGAffineTransformIdentity;
bnds.size = self.size;
rect.size = self.size;
switch (orient)
{
case UIImageOrientationUp:
return self;
case UIImageOrientationUpMirrored:
tran = CGAffineTransformMakeTranslation(rect.size.width, 0.0);
tran = CGAffineTransformScale(tran, -1.0, 1.0);
break;
case UIImageOrientationDown:
tran = CGAffineTransformMakeTranslation(rect.size.width,
rect.size.height);
tran = CGAffineTransformRotate(tran, degreesToRadians(180.0));
break;
case UIImageOrientationDownMirrored:
tran = CGAffineTransformMakeTranslation(0.0, rect.size.height);
tran = CGAffineTransformScale(tran, 1.0, -1.0);
break;
case UIImageOrientationLeft:
bnds.size = swapWidthAndHeight(bnds.size);
tran = CGAffineTransformMakeTranslation(0.0, rect.size.width);
tran = CGAffineTransformRotate(tran, degreesToRadians(-90.0));
break;
case UIImageOrientationLeftMirrored:
bnds.size = swapWidthAndHeight(bnds.size);
tran = CGAffineTransformMakeTranslation(rect.size.height,
rect.size.width);
tran = CGAffineTransformScale(tran, -1.0, 1.0);
tran = CGAffineTransformRotate(tran, degreesToRadians(-90.0));
break;
case UIImageOrientationRight:
bnds.size = swapWidthAndHeight(bnds.size);
tran = CGAffineTransformMakeTranslation(rect.size.height, 0.0);
tran = CGAffineTransformRotate(tran, degreesToRadians(90.0));
break;
case UIImageOrientationRightMirrored:
bnds.size = swapWidthAndHeight(bnds.size);
tran = CGAffineTransformMakeScale(-1.0, 1.0);
tran = CGAffineTransformRotate(tran, degreesToRadians(90.0));
break;
default:
// orientation value supplied is invalid
assert(false);
return nil;
}
UIGraphicsBeginImageContext(rect.size);
ctxt = UIGraphicsGetCurrentContext();
switch (orient)
{
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
CGContextScaleCTM(ctxt, -1.0, 1.0);
CGContextTranslateCTM(ctxt, -rect.size.height, 0.0);
break;
default:
CGContextScaleCTM(ctxt, 1.0, -1.0);
CGContextTranslateCTM(ctxt, 0.0, -rect.size.height);
break;
}
CGContextConcatCTM(ctxt, tran);
CGContextDrawImage(ctxt, bnds, self.CGImage);
copy = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return copy;
}
-(UIImage*)rotateAndScaleFromCameraWithMaxSize:(CGFloat)maxSize
{
UIImage* imag = self;
imag = [imag rotate:imag.imageOrientation];
imag = [imag scaleWithMaxSize:maxSize];
return imag;
}
-(UIImage*)scaleWithMaxSize:(CGFloat)maxSize
{
return [self scaleWithMaxSize:maxSize quality:kCGInterpolationHigh];
}
-(UIImage*)scaleWithMaxSize:(CGFloat)maxSize
quality:(CGInterpolationQuality)quality
{
CGRect bnds = CGRectZero;
UIImage* copy = nil;
CGContextRef ctxt = nil;
CGRect orig = CGRectZero;
CGFloat rtio = 0.0;
CGFloat scal = 1.0;
bnds.size = self.size;
orig.size = self.size;
rtio = orig.size.width/orig.size.height;
if ((orig.size.width <= maxSize) && (orig.size.height <= maxSize))
{
return self;
}
if (rtio > 1.0)
{
bnds.size.width = maxSize;
bnds.size.height = maxSize/rtio;
}
else
{
bnds.size.width = maxSize * rtio;
bnds.size.height = maxSize;
}
UIGraphicsBeginImageContext(bnds.size);
ctxt = UIGraphicsGetCurrentContext();
scal = bnds.size.width/orig.size.width;
CGContextSetInterpolationQuality(ctxt, quality);
CGContextScaleCTM(ctxt, scal, -scal);
CGContextTranslateCTM(ctxt, 0.0, -orig.size.height);
CGContextDrawImage(ctxt, orig, self.CGImage);
copy = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return copy;
}
@end
merci! Cela a beaucoup aidé. – timthetoolman