iphone SDK:Can't diagonal scrolling in a image array?

Question

I have a large size image. To save the memory so I don't want to load the whole picture at one time, so I divide the image into 9 pictures like an 3X3 array

036
147
258

I can scroll the smaller image pieces from one image to an adjacent image, like from(1,1) to (1,2)(1,3), or from(1,1) to (2,1)(3,1), but I can't scroll it from (1,1) to (2,2) or(3,3).

It seems I can only scroll the pic up from side to side or up and down, but not diagonally.

If I scroll diagonally, then all image looks messed up, like this:

360
471
582

How can I scroll diagonally, and/or skip sections while scrolling?

Here is my code:

.h

CGPoint first;
IBOutlet UIScrollView *scr;
NSMutableArray *ary;
int x_total;
int y_total;
BOOL move;
BOOL inside;
IBOutlet UIView *mapview;
int x_begin;
int y_begin;
int x_times;
int y_times;

Cut images

    move = NO;
    inside = NO;
    x_times = 0;
    y_total = 0;
    ary = [NSMutableArray new];



    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            UIImageView *img = [[UIImageView alloc] initWithImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_%d_%d.jpg", i ,j]]];
            [img setFrame:CGRectMake((i-1) *64, (j-1)*64, 64, 64)];
            [mapview addSubview:img];
            [ary addObject:img];

        }
    }
    x_begin = 64*2;
    y_begin = 64*2;
    x_total = 0;
    y_total = 0;

and the method to control finger touch and move

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    NSLog(@"touchesBegan");
    //Set Animation
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:1];
    [UIView setAnimationBeginsFromCurrentState:YES];

    //Trigger start
    //UITouch *touch = [touches anyObject];
    NSSet *teaches = [event allTouches];

    for (UITouch *myTouch in teaches){
        //first = [myTouch previousLocationInView:self.view];
        CGPoint currentTouchPosition = [myTouch previousLocationInView:mapview];
        //first = [myTouch previousLocationInView:mapview];
        NSLog(@"currentTouchPosition x is %f",currentTouchPosition.x);
        NSLog(@"currentTouchPosition y is %f",currentTouchPosition.y);
        NSLog(@"mapview.frame.origin.x is %d",mapview.frame.origin.x);
        NSLog(@"mapview.frame.origin.y is %d",mapview.frame.origin.y);

        if ((currentTouchPosition.x > 0 && currentTouchPosition.x <  64) && (currentTouchPosition.y > 0 && currentTouchPosition.y <  64)) {
            first = currentTouchPosition;
            inside = YES;
        }else {
            first.x = 0;
            first.y = 0;
            inside = NO;
        }       

    }
    [UIView commitAnimations];
}

Touch Moved

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

    //Touch Trigger
    NSSet *teaches = [event allTouches];

    for (UITouch *myTouch in teaches){
        CGPoint currentTouchPosition = [myTouch previousLocationInView:mapview];
        NSLog(@"currentTouchPosition.x is %d ",currentTouchPosition.x);

        if (inside) {
            if ((currentTouchPosition.x > 0 && currentTouchPosition.x <  64) && (currentTouchPosition.y > 0 && currentTouchPosition.y <  64)) {
                int x = first.x-currentTouchPosition.x;
                int y = first.y-currentTouchPosition.y;

                x_total += x;
                y_total += y;
                NSLog(@"x_total is %d",x_total);
                NSLog(@"y_total is %d",y_total);

                NSArray *arr = [mapview subviews];
                NSEnumerator *enumerator = [arr objectEnumerator];
                id anObject;
                UIImageView *tmpimg;

                while (anObject = [enumerator nextObject]) {
                    if([anObject isMemberOfClass:[UIImageView class]]) {
                        tmpimg = (UIImageView *)anObject;
                        if (x < 0) {
                            [tmpimg setFrame:CGRectMake(tmpimg.frame.origin.x-x, tmpimg.frame.origin.y, tmpimg.frame.size.width, tmpimg.frame.size.height)];
                        }else {
                            [tmpimg setFrame:CGRectMake(tmpimg.frame.origin.x-x, tmpimg.frame.origin.y, tmpimg.frame.size.width, tmpimg.frame.size.height)];
                        }
                        if (y < 0) {
                            [tmpimg setFrame:CGRectMake(tmpimg.frame.origin.x, tmpimg.frame.origin.y-y, tmpimg.frame.size.width, tmpimg.frame.size.height)];
                        }else {
                            [tmpimg setFrame:CGRectMake(tmpimg.frame.origin.x, tmpimg.frame.origin.y-y, tmpimg.frame.size.width, tmpimg.frame.size.height)];
                        }

                    }
                }
                if (y_times == 0) {
                    if (y_total >= 64/2) {
                        y_times ++;
                        for (int i = 0; i < 3; i++) {
                            int g;
                            if (i == 0) {
                                g = 0;
                            }else if (i == 1) {
                                g = 3;
                            }else if (i == 2) {
                                g = 6;
                            }
                            UIImageView *tmpimg;
                            tmpimg = [ary objectAtIndex:g];
                            [[ary objectAtIndex:g] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_%d_3.jpg" ,i]]];
                            [[ary objectAtIndex:g] setFrame:CGRectMake(tmpimg.frame.origin.x, tmpimg.frame.origin.y+(64+64*2), 64, 64)];
                            tmpimg = nil;
                        }
                        y_total= 0;
                    }
                    if (x_times == 0) {
                        if (x_total >= 64/2) {
                            x_times ++;

                            for (int i = 0; i < 3; i++) {
                                UIImageView *tmpimg;
                                tmpimg = [ary objectAtIndex:i];
                                [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_3_%d.jpg" ,i]]];
                                [[ary objectAtIndex:i] setFrame:CGRectMake(tmpimg.frame.origin.x+(64+64*2), tmpimg.frame.origin.y, 64, 64)];
                                tmpimg = nil;
                            }
                            x_total= 0;
                        }

                    }else if (x_times == 1) {
                        if (x_total >= 64) {
                            x_times ++;

                            for (int i = 3; i < 6; i++) {
                                UIImageView *tmpimg;
                                tmpimg = [ary objectAtIndex:i];
                                [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_4_%d.jpg" ,i-3]]];
                                [[ary objectAtIndex:i] setFrame:CGRectMake(tmpimg.frame.origin.x+(64+64*2), tmpimg.frame.origin.y, 64, 64)];
                                tmpimg = nil;
                            }
                            x_total= 0;


                        }else if (x_total <= -64/2) {
                            x_times --;

                                for (int i = 0; i < 3; i++) {
                                    UIImageView *tmpimg;
                                    tmpimg = [ary objectAtIndex:i];
                                    [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_0_%d.jpg" ,i]]];
                                    [[ary objectAtIndex:i] setFrame:CGRectMake(tmpimg.frame.origin.x-(64+64*2), tmpimg.frame.origin.y, 64, 64)];
                                    tmpimg = nil;
                                }
                                x_total= 0;


                        }
                    }else if (x_times == 2) {
                        if (x_total >= 64) {
                            x_times ++;
                            for (int i = 6; i < 9; i++) {
                                UIImageView *tmpimg;
                                tmpimg = [ary objectAtIndex:i];
                                [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_5_%d.jpg" ,i-6]]];
                                [[ary objectAtIndex:i] setFrame:CGRectMake(tmpimg.frame.origin.x+(64+64*2), tmpimg.frame.origin.y, 64, 64)];
                                tmpimg = nil;
                            }
                            x_total= 0;
                        }else if (x_total <= -64/2) {
                            x_times --;
                            for (int i = 3; i < 6; i++) {
                                UIImageView *tmpimg;
                                tmpimg = [ary objectAtIndex:i];
                                [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_1_%d.jpg" ,i-3]]];
                                [[ary objectAtIndex:i] setFrame:CGRectMake(tmpimg.frame.origin.x-(64+64*2), tmpimg.frame.origin.y, 64, 64)];
                                tmpimg = nil;
                            }
                            x_total= 0;
                        }
                    }else if (x_times == 3) {
                        if (x_total <= -64/2) {
                            x_times --;
                            for (int i = 6; i < 9; i++) {
                                UIImageView *tmpimg;
                                tmpimg = [ary objectAtIndex:i];
                                [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_2_%d.jpg" ,i-6]]];
                                [[ary objectAtIndex:i] setFrame:CGRectMake(tmpimg.frame.origin.x-(64+64*2), tmpimg.frame.origin.y, 64, 64)];
                                tmpimg = nil;
                            }
                            x_total= 0;
                        }
                    }
                }
                if (y_times == 1) {
                    if (y_total <= -64/2) {
                        y_times --;
                        for (int i = 0; i < 3; i++) {
                            int g;
                            if (i == 0) {
                                g = 0;
                            }else if (i == 1) {
                                g = 3;
                            }else if (i == 2) {
                                g = 6;
                            }
                            UIImageView *tmpimg;
                            tmpimg = [ary objectAtIndex:g];
                            [[ary objectAtIndex:g] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_%d_0.jpg" ,i]]];
                            [[ary objectAtIndex:g] setFrame:CGRectMake(tmpimg.frame.origin.x, tmpimg.frame.origin.y-(64+64*2), 64, 64)];
                            tmpimg = nil;
                        }
                        y_total= 0;
                    }
                    if (x_times == 0) {
                        if (x_total >= 64/2) {
                            x_times ++;

                            for (int i = 0; i < 3; i++) {
                                UIImageView *tmpimg;
                                tmpimg = [ary objectAtIndex:i];
                                if (i == 0) {
                                    [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_3_%d.jpg" ,i+3]]];
                                }else {
                                    [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_3_%d.jpg" ,i]]];
                                }
                                [[ary objectAtIndex:i] setFrame:CGRectMake(tmpimg.frame.origin.x+(64+64*2), tmpimg.frame.origin.y, 64, 64)];
                                tmpimg = nil;
                            }
                            x_total= 0;
                        }

                    }else if (x_times == 1) {
                        if (x_total >= 64) {
                            x_times ++;

                            for (int i = 3; i < 6; i++) {
                                UIImageView *tmpimg;
                                tmpimg = [ary objectAtIndex:i];
                                if (i == 3) {
                                    [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_4_%d.jpg" ,i]]];
                                }else {
                                    [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_4_%d.jpg" ,i-3]]];
                                }
                                [[ary objectAtIndex:i] setFrame:CGRectMake(tmpimg.frame.origin.x+(64+64*2), tmpimg.frame.origin.y, 64, 64)];
                                tmpimg = nil;
                            }
                            x_total= 0;


                        }else if (x_total <= -64/2) {
                            x_times --;

                            for (int i = 0; i < 3; i++) {
                                UIImageView *tmpimg;
                                tmpimg = [ary objectAtIndex:i];
                                if (i == 0) {
                                    [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_0_%d.jpg" ,i+3]]];
                                }else {
                                    [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_0_%d.jpg" ,i]]];
                                }
                                [[ary objectAtIndex:i] setFrame:CGRectMake(tmpimg.frame.origin.x-(64+64*2), tmpimg.frame.origin.y, 64, 64)];
                                tmpimg = nil;
                            }
                            x_total= 0;

                        }
                    }else if (x_times == 2) {
                        if (x_total >= 64) {
                            x_times ++;
                            for (int i = 6; i < 9; i++) {
                                UIImageView *tmpimg;
                                tmpimg = [ary objectAtIndex:i];
                                if (i == 3) {
                                    [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_5_%d.jpg" ,i-3]]];
                                }else {
                                    [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_5_%d.jpg" ,i-6]]];
                                }
                                [[ary objectAtIndex:i] setFrame:CGRectMake(tmpimg.frame.origin.x+(64+64*2), tmpimg.frame.origin.y, 64, 64)];
                                tmpimg = nil;
                            }
                            x_total= 0;
                        }else if (x_total <= -64/2) {
                            x_times --;
                            for (int i = 3; i < 6; i++) {
                                UIImageView *tmpimg;
                                tmpimg = [ary objectAtIndex:i];
                                if (i == 3) {
                                    [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_1_%d.jpg" ,i]]];
                                }else {
                                    [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_1_%d.jpg" ,i-3]]];
                                }
                                [[ary objectAtIndex:i] setFrame:CGRectMake(tmpimg.frame.origin.x-(64+64*2), tmpimg.frame.origin.y, 64, 64)];
                                tmpimg = nil;
                            }
                            x_total= 0;
                        }
                    }else if (x_times == 3) {
                        if (x_total <= -64/2) {
                            x_times --;
                            for (int i = 6; i < 9; i++) {
                                UIImageView *tmpimg;
                                tmpimg = [ary objectAtIndex:i];
                                if (i == 3) {
                                    [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_2_%d.jpg" ,i-3]]];
                                }else {
                                    [[ary objectAtIndex:i] setImage:[UIImage imageNamed:[NSString stringWithFormat:@"map14_2_%d.jpg" ,i-6]]];
                                }
                                [[ary objectAtIndex:i] setFrame:CGRectMake(tmpimg.frame.origin.x-(64+64*2), tmpimg.frame.origin.y, 64, 64)];
                                tmpimg = nil;
                            }
                            x_total= 0;
                        }
                    }
                }
                first.x = currentTouchPosition.x;
                first.y = currentTouchPosition.y;
                arr=nil;

            }else {
                first.x = 0;
                first.y = 0;
                inside = NO;
            }


        }else {
            if ((currentTouchPosition.x > 0 && currentTouchPosition.x <  64) && (currentTouchPosition.y > 0 && currentTouchPosition.y <  64)) {
                first = currentTouchPosition;
                inside = YES;
            }else {
                first.x = 0;
                first.y = 0;
                inside = NO;
            }
        }


    }
}

How big is the original image? Also, are you using a UIScrollView? — makdad
tl;dr. I think it would be helpful for us if you'd narrow down the problem a little bit more; reading a buzzilion lines of code is a bit of a barrier to helping you. — Jonathan Sterling
1280x1024 will be loaded without any problem into memory, why you need to make your life harder :) ? — Nickolay Olshevsky

Olie Olie · Accepted Answer · 2011-02-08T19:37:43

It sounds a bit like you're trying to reinvent the wheel.

Have you looked into UIScrollView?

In particular, there is sample code (ImageSuite, I believe), that specifically shows how to dice a larger image into tiles, then position them only as needed within a scroll view which allows scrolling in any direction.

This is very much how, for example, the MKMapView (Maps.app) works.

iphone SDK:Can't diagonal scrolling in a image array?

1 Answers