live move of UIPopoverController

gistfile1.m

        // check that popover won't try to move off-screen; dismiss if so
        //
        CGFloat pX      = newAttachPoint.x;
        CGFloat pY      = newAttachPoint.y;
        CGFloat pWidth  = balloon.popoverContentSize.width;
        CGFloat pHeight = balloon.popoverContentSize.height;
        CGFloat mWidth  = map.bounds.size.width;
        CGFloat mHeight = map.bounds.size.height;
        
        UIPopoverArrowDirection d = balloon.popoverArrowDirection;
        
        CGFloat threshold = 20;
        CGFloat arrowSize = 30;
        
        if (d == UIPopoverArrowDirectionRight && pX > mWidth - threshold                        || // popup on left hitting right edge of map
            d == UIPopoverArrowDirectionRight && pX - arrowSize - pWidth - threshold < 0        || // popup on left hitting left edge of map
            d == UIPopoverArrowDirectionLeft  && pX > mWidth - pWidth - arrowSize - threshold   || // popup on right hitting right edge of map
            d == UIPopoverArrowDirectionLeft  && pX < threshold                                 || // popup on right hitting left edge of map
            d == UIPopoverArrowDirectionDown  && pY > mHeight - threshold                       || // popup on top hitting bottom edge of map
            d == UIPopoverArrowDirectionDown  && pY - pHeight - arrowSize < threshold           || // popup on top hitting top edge of map
            d == UIPopoverArrowDirectionUp    && pY + arrowSize + pHeight > mHeight - threshold || // popup on bottom hitting bottom edge of map
            d == UIPopoverArrowDirectionUp    && pY < threshold                                 || // popup on bottom hitting top edge of map
            d == UIPopoverArrowDirectionRight && pY - (pHeight / 2) < threshold                 || // popup on left hitting top edge of map
            d == UIPopoverArrowDirectionRight && pY + (pHeight / 2) > mHeight - threshold       || // popup on left hitting bottom edge of map
            d == UIPopoverArrowDirectionLeft  && pY - (pHeight / 2) < threshold                 || // popup on right hitting top edge of map
            d == UIPopoverArrowDirectionLeft  && pY + (pHeight / 2) > mHeight - threshold       || // popup on right hitting bottom edge of map
            d == UIPopoverArrowDirectionDown  && pX + (pWidth  / 2) > mWidth  - threshold       || // popup on top hitting right edge of map
            d == UIPopoverArrowDirectionDown  && pX - (pWidth  / 2) < threshold                 || // popup on top hitting left edge of map
            d == UIPopoverArrowDirectionUp    && pX - (pWidth  / 2) < threshold                 || // popup on bottom hitting left edge of map
            d == UIPopoverArrowDirectionUp    && pX + (pWidth  / 2) > mWidth  - threshold)         // popup on bottom hitting rigth edge of map
            
            [balloon dismissPopoverAnimated:NO];
        
        else
            [balloon presentPopoverFromRect:CGRectMake(newAttachPoint.x, newAttachPoint.y, 1, 1) 
                                     inView:map
                   permittedArrowDirections:balloon.popoverArrowDirection 
                                   animated:NO];