CODEWITHSUNDEEP
iphoneobjective-ccocoa-touch
Regan
Regan

Reputation: 1497

Trouble with CGRectMake

I have been trying to create a grid on the iPhone of 16x16 images.

- (void)viewDidLoad {
    [super viewDidLoad];

    int xLocation = 0;

    for (int i=0; i <= 619; i++) {


        if (((i % 30) == 0) && i != 0) { //if at end of column (30th row), moves x over 16 px to next column
            xLocation += 16;
        }
        else {;}


    CGRect imageRect = CGRectMake( xLocation, (16*i), 16, 16);
    UIImageView *image = [[UIImageView alloc] initWithFrame:imageRect];
    [image setImage:[UIImage imageNamed:@"Untitled-1.png"]];
    [image setOpaque:YES];

        NSLog(@"%d", xLocation);


    [self.view addSubview:image];
    [image release];
    }

The problem is the int xLocation. For some reason, CGRectMake uses 0 in the x-coordinate slot instead of xLocation. I say "instead of" because the NSLog below it reveals that the xLocation has the values that I want it to, so the assignment of the values is working fine. What is going on here?

Upvotes: 1

Views: 630

Answers (3)

Casey Fleser
Casey Fleser

Reputation: 5787

Casting xLocation as an int in your NSLog will certainly work, but you could also use:

NSLog(@"imageRect %@", NSStringFromCGRect(imageRect));

There are a whole series of NSStringFromXXX helper functions that come in handy from time to time.

Upvotes: 3

user467105
user467105

Reputation:

The xLocation is 0 for the first column and it is being increased for each column but the y coordinate is not being reset to 0 for each new column. It just keeps increasing based on i. So the columns from the second onward are just off screen at the right xLocation but a high y value.

Try changing the imageRect calculation to:

CGRect imageRect = CGRectMake( xLocation, (16*(i % 30)), 16, 16);

Upvotes: 2

Peter DeWeese
Peter DeWeese

Reputation: 18343

%d doesn't present float's properly. Use %f or convert xLocation to an int:

NSLog(@"%d", (int)xLocation);

You can also simplify your xLocation calculation readability by calculating it each time, something like

16 * (i / 30)

The overhead is minimal on modern processors.

Upvotes: 1

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