I cant seem to figure this out, I have a Objective-C function that returns an NSArray, I know for sure that data inside the NSArray contains CGPoint objects How in the world do I cast this to an Array
Here is the function
+(NSArray *)translatePoints:(NSArray *)points fromView:(UIView *)fromView toView:(UIView *)toView
{
NSMutableArray *translatedPoints = [NSMutableArray new];
// The points are provided in a dictionary with keys X and Y
for (NSDictionary *point in points) {
// Let's turn them into CGPoints
CGPoint pointValue = CGPointMake([point[#"X"] floatValue], [point[#"Y"] floatValue]);
// Now translate from one view to the other
CGPoint translatedPoint = [fromView convertPoint:pointValue toView:toView];
// Box them up and add to the array
[translatedPoints addObject:[NSValue valueWithCGPoint:translatedPoint]];
}
return [translatedPoints copy];
}
Your translatesPoints method returns an NSArray that contains NSValues that wrap CGPoints. Let's create such an array:
let arr:NSArray = [NSValue(CGPoint: CGPointMake(1,2)), NSValue(CGPoint: CGPointMake(3,4))]
You can get the values from this array and call CGPointValue() on them:
for val in arr as [NSValue] {
let point = val.CGPointValue()
println("CGPoint = (\(point.x), \(point.y))")
}
If you want, you can convert the entire NSArray to a Swift array of CGPoints like this:
let points = (arr as [NSValue]).map({$0.CGPointValue()})
Now points has the type [CGPoint].
Related
I am trying to figure out what the fastest/cleanest way to sort an array of CGPoints would be. I think I could achieve this using loops but that might not be the fastest and I hope it isn't the cleanest way. I would like to take an array of random CGPoints and sort them say by smallest x coordinate to largest, or smallest x and y coordinate to largest.
After the correct comment by Chuck, I've updated the answer using the sortUsingComparator method:
Here is the complete code with sample data:
First we generate 100 random values that we enter to the Array:
NSMutableArray *testArray = [[NSMutableArray alloc] initWithCapacity:100];
for (int i=0; i<100; i++) {
CGPoint testPoint = CGPointMake(arc4random()%100, arc4random()%100);
[testArray addObject:[NSValue valueWithCGPoint:testPoint]];
}
and here is the actual code to sort the array:
[testArray sortUsingComparator:^(id firstObject, id secondObject) {
CGPoint firstPoint = [firstObject CGPointValue];
CGPoint secondPoint = [secondObject CGPointValue];
return firstPoint.x>secondPoint.x;
}];
finally we can verify that the array was sorted, by printing it:
NSLog(#"%#",testArray);
The C qsort() function is probably your best bet if you just have a plain array of CGPoints. Something like this:
int compareXCoords(CGPoint *a, CGPoint *b) {
return b->x - a->x;
}
// Later:
CGPoint points[100];
// initialize points somehow
qsort(points, 100, sizeof(CGPoint), compareXCoords);
// points is now sorted by the points' x coordinates
According to my comment, it's a good solution insert them on a NSMutableArray keeping the sort you decide.
You have to do something like this:
NSMutableArray *array = [[NSMutableArray alloc] initWithCapacity:1];
CGPoint candidate;
// Look for the position it has to be
int 0;
for (CGPoint point in array) {
i++;
// Compare candidate with current point
// You have to define this condition, when point is greater than candidate
if (point > candidate) {
break;
}
}
[array insertObjectAtIndex:i-1];
Maybe my code has some errors, I can't check if it's correct now.
Even though i know there are at least 2 or 3 topics with this name, i didnt find a proper answer so far to my problem :
I want to edit a Plist (which has been created by zwoptex (image/animations program)) in order to divide every number in it by 2.
So in my plist i do have some keys like "spriteOffset" with {{182, 160}, {58,75}} or {192, 165} as value. Those are NSStrings, and i just want to modify the numbers so i need to check if there's a "{" or a space or such, then casting the number.
The thing is i don't really know how to do it.....
Also, it seems that i'm missing something with my plist management. I've put some NSLogs for displaying every of those strings in my plist, but.... nothing gets displayed...
So here is my code :
-(void)DivideValues
{
for(NSString * plistName in plistSubpathsByName)
{
NSMutableDictionary* infoDict = [NSMutableDictionary dictionaryWithContentsOfFile:[NSString stringWithFormat:#"%#.plist",plistName]];
for(NSDictionary * sprite in [infoDict objectForKey:#"frames"])
{
for(NSString * string in [infoDict objectForKey:#"spriteColorRect"])
{
NSLog(#"%#",string);
}
for(NSString * string in [infoDict objectForKey:#"spriteOffset"])
{
NSLog(#"%#",string);
}
for(NSString * string in [infoDict objectForKey:#"spriteSize"])
{
NSLog(#"%#",string);
}
for(NSString * string in [infoDict objectForKey:#"spriteSourceSize"])
{
NSLog(#"%#",string);
}
for(NSString * string in [infoDict objectForKey:#"textureRect"])
{
NSLog(#"%#",string);
}
}
}
}
Thanks for any response, and i wish you all good luck for your career/passion
First of all, you should replace [infoDict objectForKey:#"spriteColorRect"] with [sprite objectForKey:#"spriteColorRect"], since the sprite is probably the dict containing further information.
You don't see any logs because -objectForKey: returns nil for a key that does not exist.
For changing the values, you might try to create a CGPoint or CGRect from the string, then changing it and finally converting it back to a string. (CGPointFromNSString() and NSStringFromCGPoint)
To save the modified version of your dictionary use NSDictionary's -writeToFile:atomically:.
The reason you example logs nothing is most likely because your inner for..in loops are probably looking in the wrong dictionary: the outer loop gets a dictionary sprite, so shouldn't the inner loops be looking at keys in that dictionary?
If you want to read a property list in, change some values in it, and write the same property list back out, you might find it useful to look at the NSPropertyListSerialization class -- it lets you quickly get a structure of mutable arrays/dictionaries from plist data, so you can iterate into them however you'd like to change values within, then serialize the whole thing back to data again. (If you use dictionaryWithContentsOfFile: you'll get a mutable dictionary, but all the containers within it will be immutable, so you'd have to do mutableCopy and swizzle contents all over the place during your iteration.)
No time to write up more detail at the moment, but I might edit the answer later if looking up the docs for NSPropertyListSerialization doesn't help you.
Ok I did succeed so if anyone is interested here is the code :
-(void)DivideValues
{
for(NSString * xflName in [xflSubpathsByName objectEnumerator]){
NSMutableDictionary* infoDict = [NSMutableDictionary dictionaryWithContentsOfFile:[sourceFolder stringByAppendingPathComponent:xflName]];
NSDictionary * dictionary = [infoDict objectForKey:#"frames"];
NSMutableDictionary * mutabledictionary = [[dictionary mutableCopy] autorelease];
for(NSString * pngFileName in dictionary) {
NSDictionary * sprite = [dictionary objectForKey:pngFileName];
NSLog(pngFileName);
NSMutableDictionary * mutablesprite = [[sprite mutableCopy] autorelease];
NSString * newstring = [self castSpriteRect:[sprite objectForKey:#"spriteColorRect"]];
[mutablesprite setObject:newstring forKey:#"spriteColorRect"];
newstring = [self castSprite:[sprite objectForKey:#"spriteOffset"]];
[mutablesprite setObject:newstring forKey:#"spriteOffset"];
newstring = [self castSprite:[sprite objectForKey:#"spriteSize"]];
[mutablesprite setObject:newstring forKey:#"spriteSize"];
newstring = [self castSprite:[sprite objectForKey:#"spriteSourceSize"]];
[mutablesprite setObject:newstring forKey:#"spriteSourceSize"];
newstring = [self castSpriteRect:[sprite objectForKey:#"textureRect"]];
[mutablesprite setObject:newstring forKey:#"textureRect"];
[mutabledictionary setObject:mutablesprite forKey:pngFileName];
}
[infoDict setObject:mutabledictionary forKey:#"frames"];
[infoDict writeToFile:[sourceFolder stringByAppendingPathComponent:xflName] atomically:NO];
}
if(!cancelling)
++digestStage;
else
digestStage = End;
}
-(NSString *)castSprite:(id)obj{
CGPoint point = NSPointFromString((NSString *)obj);
int i = (int)point.x%2 == 0 ?(int)point.x/2:1+(int)point.x/2;
int j = (int)point.y%2 == 0 ?(int)point.y/2:1+(int)point.y/2;
NSString * res = [NSString stringWithFormat:#"{%d, %d}",i,j];
return res;
}
-(NSString *)castSpriteRect:(id)obj{
CGRect point = NSRectFromString((NSString *)obj);
int i = (int)point.origin.x%2 == 0 ?(int)point.origin.x/2:1+(int)point.origin.x/2;
int j = (int)point.origin.y%2 == 0 ?(int)point.origin.y/2:1+(int)point.origin.y/2;
int y = (int)point.size.width%2 == 0 ?(int)point.size.width/2:1+(int)point.size.width/2;
int x = (int)point.size.height%2 == 0 ?(int)point.size.height/2:1+(int)point.size.height/2;
NSString * res = [NSString stringWithFormat:#"{{%d, %d}, {%d, %d}}",i,j,y,x];
return res;
}
I am trying to find the closest "player" to a "ball" and each of these objects are CCSprite Objects. This is my first app, so if there's a better way to do this, feel free to suggest it :)
Here's my code so far:
for(CCSprite *currentPlayer in players) {
// distance formula
CGFloat dx = ball.position.x - currentPlayer.position.x;
CGFloat dy = ball.position.y - currentPlayer.position.y;
CGFloat distance = sqrt(dx*dx + dy*dy);
// add the distance to the distances array
[distances addObject:[NSNumber numberWithFloat:distance]];
NSLog(#"This happen be 5 times before the breakpoint");
NSLog(#"%#", [NSNumber numberWithInt:distance]);
}
So this seems to work well; it logs each distance of the player from the ball. But then when I loop through my "distances" array, like this:
for(NSNumber *distance in distances ) {
NSLog(#"Distance loop");
NSLog(#"%#", [NSNumber numberWithInt:distance]);
}
And this is logging a huge number each time, like 220255312. I declare my distances array like this:
// setting the distance array
NSMutableArray *distances = [[NSMutableArray alloc] init];
What am I doing wrong?
Thanks for your time!
Use distance for the #"%#" like this:
for(NSNumber *distance in distances ) {
NSLog(#"Distance loop");
NSLog(#"%#", distance);
}
[NSNumber numberWithInt:distance]
In your first part distance is a CGFloat.
In the second part distance is a NSNumber.
numberWithInt can't take a NSNumber as its argument.
Hope this helps!
CCSprite *nearestPlayer;
for(CCSprite *currentPlayer in players) {
if(nearestPlayer == nil){
nearestPlayer = currentPlayer;
}
if(ccpDistance(ball.position, currentPlayer.position) < ccpDistance(ball.position, nearestPlayer.position)){
nearestPlayer = currentPlayer;
}
}
I have been trying to create an array stating the location of a UIImageView in an app I've been working on. What I am trying to do is by using an array I can store the location of my "player" image by using its x,y and z coordinates. The script I am trying to accomplish would look like
NSArray *location[3];
-(IBAction)startup;{
[location addObject: player.center.x];
[location addObject: player.center.y];
[location addObject: playerheight];
}
So I will be able to access this array to move my "player" on the screen in "3-dimensions", but I don't know how to convert the CGpoint values to NSValues so they can be used in the array, is there a simple way to do this inside of the array?
To convert floating point values to objects, use NSNumber. NSValue has wrappers for geometric types like CGPoint. Either would work for you.
[NSValue valueWithCGPoint:player.center];
[NSNumber numberWithFloat:player.center.x];
[NSNumber numberWithFloat:player.center.y];
To addition for the first answer.
When you'll need to read CGPoint back from your array, you can use something like that:
CGPoint point = [(NSValue *)[pointsArray objectAtIndex:i] CGPointValue];
Also note that there's no addObject method for NSArray (you can't add objects to an NSArray after its been created); you want NSMutableArray.
Instead of:
NSArray *location[3];
you probably want something more like:
NSMutableArray *location = [NSMutableArray arrayWithCapacity:3];
Does it have to be an NSArray? Why not use an array of structs?
typedef struct {
CGPoint location;
CGFloat height;
} PlayerLocation;
PlayerLocation players[3];
players[0].location = player.center;
players[0].height = playerheight;
Or depending on your design it may make more sense to declare an objective-C class that contains the x,y,z coordinates as ivars and store those objects into an NSArray.
#interface PlayerLocation : NSObject {
CGPoint location;
CGFloat height;
}
#end
Is it possible to compare touch coordinates made by the users on the UIView to the one store in a plist or txt format? The argument looks like this;
if (user touch coordinate == touch coordinate stored in plist or text)
then
(do something)
else
(do something)
If possible in what format should i write the coordinates in the list and how to associate it inside the program?
thanks in advance and sorry if you find my question a bit noobie.
Not sure if there's a one-liner solution.
On a UITouch instance, the locationInView: method returns a CGPoint struct (x and y coordinates, both of type float). So you can store the x and y coordinates in your plist, then compare them with your current touch's x and y coordinates.
EDIT:
Also, when comparing the coordinates, you probably want to use the distance between the two points to determine when you have a "hit".
EDIT:
Below is sample code for loading and writing to a property list, where the values are based on a NSDictionary:
- (NSMutableDictionary *)loadDictionaryFromPList: (NSString *)plistName
{
NSString *plistPath = [[NSBundle mainBundle] pathForResource:plistName ofType:#"plist"];
NSDictionary *immutableDictionary = [NSDictionary dictionaryWithContentsOfFile: plistPath];
NSMutableDictionary *mutableDictionary = [NSMutableDictionary dictionaryWithDictionary: immutableDictionary];
return mutableDictionary;
}
- (void)saveDictionary: (NSDictionary *)mySettings toPList: (NSString *)plistName
{
NSString *plistPath = [[NSBundle mainBundle] pathForResource:plistName ofType:#"plist"];
[mySettings writeToFile: plistPath atomically: YES];
}
The method to calculate the distance between the two locations of the UITouches:
-(CGFloat) distanceBetween: (CGPoint) point1 and: (CGPoint)point2
{
CGFloat dx = point2.x - point1.x;
CGFloat dy = point2.y - point1.y;
return sqrt(dx*dx + dy*dy );
}
And finally, the code that uses the values in the property list to determine if the user hit the previous location:
CGPoint currentTouchLocation = [currentTouch locationInView:self];
// Lookup last Touch location from plist, and handle case when current Touch matches it:
NSMutableDictionary *mySettings = [self loadDictionaryFromPList: #"MySettings"];
NSNumber *lastXCoordinate = [mySettings objectForKey:#"lastXCoordinate"];
NSNumber *lastYCoordinate = [mySettings objectForKey:#"lastYCoordinate"];
if (lastXCoordinate && lastYCoordinate)
{
CGPoint lastTouchLocation = CGPointMake([lastXCoordinate floatValue], [lastYCoordinate floatValue]);
CGFloat distanceBetweenTouches = [self distanceBetween: currentTouchLocation and: lastTouchLocation];
if (distanceBetweenTouches < 25) // 25 is just an example
{
// Handle case where current touch is close enough to "hit" previous one
NSLog(#"You got a hit!");
}
}
// Save current touch location to property list:
[mySettings setValue: [NSNumber numberWithFloat: currentTouchLocation.x] forKey: #"lastXCoordinate"];
[mySettings setValue: [NSNumber numberWithFloat: currentTouchLocation.y] forKey: #"lastYCoordinate"];
[self saveDictionary:mySettings toPList: #"MySettings"];
The functions you're probably looking for are NSStringFromCGPoint() and CGPointFromString().
But two touch coordinates will almost certainly never be the exact same. You should almost never be comparing CGFloats with ==, let alone ones you get from such an analog input as a finger touch. You need to compare whether they are "close enough." See this blog for a good example of how to measure the distance between two points. You want that result to be less than some value (epsilon, or "a small number") that is appropriate for your purposes.