App crashes due to memory Warning on iPad 3

问题:

I am drawing lines on UIImage and my image is in UIImageView. First time drawing process goes fine and I assign the new Image to UIImageView but when I repeat the process it gives me memory warning and app crashes:

Terminating in response to backboard's termination.

I have profiled my app and the CG raster data was taking 273 MB and overall its 341 MB Live Bytes. Also wrapped code in in autorelease pool but didn't get the success. My Code

UIGraphicsBeginImageContext(imageView.image.size);

[imageView.image drawAtPoint:CGPointMake(0, 0)];


context2=UIGraphicsGetCurrentContext(); 
for(int i=0; i<kmtaObject.iTotalSize; i++)
    {
        kmtaGroup=&kmtaObject.KMTA_GROUP_OBJ[i];

        //NSLog(@"Group  # = %d",i);

        for (int j=0; j<kmtaGroup->TotalLines; j++)
        {

            lineObject=&kmtaGroup->Line_INFO_OBJ[j];

           // NSLog(@"Line # = %d",j);
           // NSLog(@"*****************");
            x0 = lineObject->x0;
            y0= lineObject->y0;
            x1= lineObject->x1;
            y1= lineObject->y1;
            color= lineObject->Color;
            lineWidth= lineObject->LinkWidth;
            lineColor=[self add_colorWithRGBAHexValue:color];
            linearColor=lineColor;

            // Brush width
            CGContextSetLineWidth(context2, lineWidth);
            // Line Color
            CGContextSetStrokeColorWithColor(context2,[linearColor CGColor]);


            CGContextMoveToPoint(context2, x0, y0);

            CGContextAddLineToPoint(context2, x1, y1);
            CGContextStrokePath(context2);

        }
    }


    newImage=UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();
    imageView.image=newImage;

回答1:

So it just happened I stumbled onto a similar issue. I was assigning an image to the image view where the image itself was previously retained by other objects, being processed and such... The result was that the image view did indeed leak everyone of those images somehow.

The solution I used was to create a copy of the image on the level of the CGImage before assigning it to the image view. I guess there must be an issue with the bitmaps or something. Anyway try creating a copy like this:

CGImageRef cgCopy = CGImageCreateCopy(originalImage.CGImage);
UIImage *copiedImage = [[UIImage alloc] initWithCGImage:cgCopy scale:originalImage.scale orientation:originalImage.imageOrientation];
    CGImageRelease(cgCopy);
imageView.image = copiedImage;

回答2:

Max resolution used in iOS device is 1024x1024. we can't use more than that size. use 2x and 3x images for respective device sizes.