I created a Grid of Images.
The frames of those images are squares-shaped(CGRects).
Unfortunately the images fill-fits the square unproportionally.
But I would like to "crop" or "mask" the given image. Which means my frames will show only parts of an image but proportionally correct. I tried contentModes of UIImageView but no luck.
for(int index = 0; index < (_cols*_rows) ;index++)
{
NSValue *value = [myArray objectAtIndex:index];
CGRect myrect = [value CGRectValue];
UIImageView *myImageView = [[UIImageView alloc] initWithImage:myImage];
myImageView.frame = myrect;
[self addSubview:myImageView];
[myImageView release];
}
Are you sure contentMode won't do what you want? If I understand you correctly, UIViewContentModeScaleAspectFill will do exactly what you describe.
Related
For a modular UIPickerView within an UIPopoverController I need to calculate the maximum size (CGRect) of a NSString.
UIPickerView has one component. Values are single line strings.
To calculate the size, I need the current UIFont from the UIPickerView. The following works for UILabel,
UIFont* fontFromUILabel = [UIFont systemFontOfSize:UILabel.font.pointSize];
but what's the equivalent for UIPickerView?
UIFont* fontFromUIPickerViewSelectedState = ????;
float maxWidth = 0.0f;
for(int i = 0; i < [MY_STRING_VALUES count]; i++){
NSString* string = [MY_STRING_VALUES objectAtIndex:i];
CGSize rect = [string sizeWithAttributes:#{
NSFontAttributeName:fontFromUIPickerViewSelectedState }];
if(rect.width > maxWidth){
maxWidth = rect.width;
NSLog(#"new MAX WIDTH: %f",maxWidth);
}
}
//...
//present UIPopoverViewController with calculated size
[_popOver setPopoverContentSize: CGSizeMake(maxWidth,200.0)];
[_popOver presentPopoverFromRect:[(UIButton*)sender frame] inView:self.view permittedArrowDirections:UIPopoverArrowDirectionDown|UIPopoverArrowDirectionUp animated:TRUE];
And yes, I could get the font from the xib, but this should be a modular solution which works every time!
You can probably use viewForRow:forComponent: to get one of the sub-controls to get its font.
I'm building a application in whom one of the features will be shoving geographic coordinates on a custom UIImageView. I'm bad at math so I cant seem to get the right values. This is what I'm doing:
I have a image that is 2048x2048 and I put it in a UIScrollView and when I get coordinates, let's say "Sydney -33.856963, 151.215219" I turn them into a UIView coordinates (x,y)
- (void)viewDidLoad
{
[super viewDidLoad];
scrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width,self.view.frame.size.height)];
scrollView.delegate = self;
scrollView.showsVerticalScrollIndicator = YES;
scrollView.scrollEnabled = YES;
scrollView.userInteractionEnabled = YES;
[scrollView setBounces:NO];
scrollView.minimumZoomScale = 0.5;
scrollView.maximumZoomScale = 100.0;
mainImageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, IMAGE_SIZE, IMAGE_SIZE)];
mainImageView.image = [UIImage imageNamed:#"map.jpg"];
mainImageView.contentMode = UIViewContentModeScaleAspectFit;
tipScroll.contentSize = CGSizeMake(IMAGE_SIZE, IMAGE_SIZE);
[scrollView addSubview:mainImageView];
[self.view addSubview:scrollView];
NSString* fileContents = #"-33.856963,151.215219";
NSArray* pointStrings = [fileContents componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
for (int i = 0; i<[pointStrings count]; i++) {
NSArray* latLonArr = [currentPointString componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:#","]];
[self getCoordinates:latLonArr];
}
}
-(void)getCoordinates:(NSArray *)latLonArr{
double comparatorWidth = IMAGE_SIZE/360.0f;
double comparatorHeight = IMAGE_SIZE/180.0f;
double Xl = [[latLonArr objectAtIndex:1] doubleValue]; //151.215219
double Yl = [[latLonArr objectAtIndex:0] doubleValue]; //-33.856963
coordX = (Xl+180.0f)*comparatorWidth;
coordY = (90.0f-Yl)*comparatorHeight;
UIImage *image=[UIImage imageNamed:[NSString stringWithFormat:#"star.png"]];
imageView=[[UIImageView alloc] init];
[imageView setFrame:CGRectMake(coordX,coordY,10,10)];
[imageView setImage:image];
[scrollView addSubview:imageView];
}
The further I go from the center coordinates (0,0) the more the points are not accurate. If I have coordinates for a city in West Africa it will be right on spot, but Sydney is a lot off. How can I fix this?
I think the problem is that the earth is not flat. That means that you can not simple convert geo coordinates to 2-dimensional system of the view. http://en.wikipedia.org/wiki/Geographic_coordinate_system
Check this question and the correct answer:
Converting longitude/latitude to X/Y coordinate
Look at the white horizontal lines on the image you posted. They're not evenly spaced out - they get wider towards the bottom of the image. This means that your map image is not made using an Equirectangular projection, and is probably a Mercator projection image.
The code you have posted which converts lat/long to Y/X just by offset and scaling would only work for Equirectangular projection images.
For mercator projections, the conversion is more complex. Please see Covert latitude/longitude point to a pixels (x,y) on mercator projection.
So you have two options:
A) Use equirectangular projection map images
B) Continue using Mercator map images, and fix your lat/long -> Y/X conversion algorithm
I want to create an simple app that will contain one centered image at the first start screen, than upon swipe gesture(right, left) change images.
I'm very new to this so here is what I though is what I'm looking for http://idevzilla.com/2010/09/16/uiscrollview-a-really-simple-tutorial/ .
This is the code I have in my controller implementation :
- (void)viewDidLoad
{
[super viewDidLoad];
NSMutableDictionary *myDictionary = [[NSMutableDictionary alloc] init];
[myDictionary setObject:#"img1.jpg" forKey:#"http://www.testweb.com"];
[myDictionary setObject:#"img2.jpg" forKey:#"http://www.test2.com"];
UIScrollView *scroll = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
scroll.pagingEnabled = YES;
NSInteger numberOfViews = [myDictionary count];
for (NSString* key in myDictionary) {
UIImage * image = [UIImage imageNamed:[NSString stringWithFormat:[myDictionary objectForKey:key]]];
CGRect rect = CGRectMake(10.0f, 90.0f, image.size.width, image.size.height);
UIImageView * imageView = [[UIImageView alloc] initWithFrame:rect];
[imageView setImage:image];
CGPoint superCenter = CGPointMake([self.view bounds].size.width / 2.0, [self.view bounds].size.height / 2.0);
[imageView setCenter:superCenter];
self.view.backgroundColor = [UIColor whiteColor];
[scroll addSubview:imageView];
}
scroll.contentSize = CGSizeMake(self.view.frame.size.width * numberOfViews, self.view.frame.size.height);
[self.view addSubview:scroll];
}
My first issue here is that I get img2 on my initial screen instead of img1. And second issue is when I swipe right I get white screen and no image on it. Any suggestions what I missed, what I can try/read etc?
EDIT :
I'm looking to do this the "lightest" possible way, using no fancy galleries api etc. Just display couple of really small images(i.e 200x200 px) centered on the screen that I can swipe back and forth(should't be too hard). Well everything is hard when learning a new language.
There is a project on github MWPhotoBrowser that allows you to put in a set of images which are viewed one at a time. You can then scroll from one image to the next with a swipe gesture. It is also easy to add functionality and it should give you a good understanding of how this is done. There is also Apple's PhotoScroller example which gives you straight forward code in how to do this same thing and also tile your images. Since you are new to iOS you may want to first look at both of these examples or possibly just use them as your photo viewer.
Your problem is likely to be the fact that you are setting CGRect rect = CGRectMake(10.0f, 90.0f, image.size.width, image.size.height); for both of your image views. This means that both of your UIImageView objects are placed in exactly the same position (both are positioned at 10.f on the x-coordinate of the scrollview). As the second image view is added last it covers the first and means that there is white space to the right of it.
In order to fix this you could try something like...
- (void)viewDidLoad
{
//your setup code
float xPosition = 10.f;
for (NSString* key in myDictionary) {
UIImage * image = [UIImage imageNamed:[NSString stringWithFormat:[myDictionary objectForKey:key]]];
CGRect rect = CGRectMake(xPosition, 90.0f, image.size.width, image.size.height);
xPosition += image.size.width;
//rest of your code...
}
//rest of your code
}
The above would mean that the second view is positioned on the x-coordinate at 10 + the width of the first image. Note that I haven't tested my answer.
First off the images are placed on top of each other.
CGPoint superCenter = CGPointMake([self.view bounds].size.width / 2.0, [self.view bounds].size.height / 2.0);
[imageView setCenter:superCenter];
Right here you are setting both images to be placed at the center of the screen. The second thing is your using an NSDictionary and looping through the keys. NSDictionary are not orders like an array is. You would have to sort the keys to us it in a specific order. So Barjavel had it right but skipped over the fact your setting the images to center. Try this:
- (void)viewDidLoad
{
[super viewDidLoad];
NSArray *myArray = [[NSArray alloc] initWithObjects:#"img1.jpg", #:image2.jpg", nil];
UIScrollView *scroll = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
scroll.pagingEnabled = YES;
NSInteger numberOfViews = [myArray count];
int xPosition = 0;
for (NSString* image in myArray) {
UIImage * image = [UIImage imageNamed:image];
CGRect rect = CGRectMake(xPosition, 90.0f, image.size.width, image.size.height);
UIImageView * imageView = [[UIImageView alloc] initWithFrame:rect];
[imageView setImage:image];
self.view.backgroundColor = [UIColor whiteColor];
[scroll addSubview:imageView];
xPosition += image.size.width;
}
scroll.contentSize = CGSizeMake(self.view.frame.size.width * numberOfViews, self.view.frame.size.height);
[self.view addSubview:scroll];
}
.h file
#interface AppViewController : UIViewController {
...
UIImageView *imageViewArray[3][5];// not using any #property for this
...
}
...
#define FOR(j,q) for (int j = 0; j < q; j++)
.m file
ViewDidLoad{
FOR(i,5){
FOR(j,3)
{
image_names[0] = [UIImage imageNamed:[NSString stringWithFormat:#"%d.png",j]];
imageViewArray[j][i] = [[UIImageView alloc] initWithImage: image_names[0]];
CGRect newFrame ;
newFrame = CGRectMake(60+(j*130), 110+(150*i),130,136);
imageViewArray[j][i].frame = newFrame;
[self.view addSubview:imageViewArray[j][i]];
}
}
}
//clear the previous images and call a method to add new
-(IBAction)Change{
FOR(i,5)
FOR(p,3)
imageViewArray[p][i].image = nil;
[self ImageSwitch];
}
-(void)ImageSwitch{
FOR(i,5){
FOR(j,3)
{
image_namesTmp[0] = [UIImage imageNamed:[NSString stringWithFormat:#"%d.png",j+3]];
imageViewArray[j][i] = [[UIImageView alloc] initWithImage: image_namesTmp[0]];
CGRect newFrame ;
newFrame = CGRectMake(60+(j*130), 110+(150*i),130,136);
imageViewArray[j][i].frame = newFrame;
[self.view addSubview:imageViewArray[j][i]];
}
}
}
when i press the button for the first time it works fine(old images get replaced with new ones),but if i do it second time
imageViewArray[p][i].image = nil;
this line wont work and all the previous images still remain there and new images are overlapping with the present ones
In the ImageSwitch method you are always creating new instances of UIImageView.
imageViewArray[j][i] = [[UIImageView alloc] initWithImage: image_namesTmp[0]];
At this point, there already is a reference to UIImageView stored in the variable. You are losing your reference to it and since you alloc/inited it, you will most probably also leak its memory. Moreover, you are adding new UIImageViews to the view hierarchy, but you are not removing the old ones.
Try something like this:
[imageViewArray[j][i] removeFromSuperview];
[imageViewArray[j][i] release];
imageViewArray[j][i] = [[UIImageView alloc] initWithImage: image_namesTmp[0]];
Second time you set your images you don't need to recreate the UIImageView objects. Your ImageSwitch method is better declared as,
-(void)ImageSwitch{
FOR(i,5){
FOR(j,3)
{
imageViewArray[j][i].image = [UIImage imageNamed:[NSString stringWithFormat:#"%d.png",j+3]];
}
}
}
Just changing the images will suffice and that's what you need to do.
You need an NSMutableArray of ImageViews. In your header declare the NSMutableArray:
NSMutableArray *_imageViewArray;
Then in your viewDidLoad method initialize the array and then populate it with your image views.
_imageViewArray = [[NSMutableArray alloc]init];
for (int i =0; i < imageNames; i++) {
UIImageView *tempImageView = [[UIImageView alloc]initWithImage:[UIImage imageNamed:[imageNames objectAtIndex:i];
[_imageViewArray addObject:tempImageView];
[tempImageView release];
}
So thats the image view array populated, you may do it a different way but thats up to you.
To switch the views over what I would do is like so...
[self.view removeAllSubviews]; // gets rid of all previous subviews.
[self.view addSubview:[_imageViewArray objectAtIndex:3]];// could be any number. generate a random number if you want.
Thats all you would need to do. If you wanted to know which image view was being displauyed the maybe declare an instance of UIImageView in your header called _currentImageView and then you can remove just that image view instead of all subviews.
Hope this helped.
How can I create and position a new imageview in objective-c?
Thanks!
I tried this but it doesnt seem to do anything...
-(void)drawStars{ //uses random numbers to display a star on screen
//create random position
int xCoordinate = arc4random() % 10;
int yCoordinate = arc4random() % 10;
UIImageView *starImgView = [[UIImageView alloc] initWithFrame:CGRectMake(xCoordinate, yCoordinate, 58, 40)]; //create ImageView
starImgView.image = [UIImage imageNamed:#"star.png"];
[starImgView release];
I placed this method in my viewcontroller. I see some CG stuff do I need to import core graphics or something? (what is core graphics anyway?)
You are asking about iPhone image view. Right? Then try this
UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(10, 10, 100, 50)];
This will create an image view of 100 x 50 dimension and locating (10, 10) of parent view.
Check the reference manual for UIImageView and UIView. You can set an image by using image property of imageView.
imgView.image = [UIImage imageNamed:#"a_image.png"];
And you can use the contentMode property of UIView to configure how to fit the image in the view. For example you can use
imgView.contentMode = UIViewContentModeCenter to place the desired image to the center of the view. The available contentModes are listed here
You haven't added your view as a subview to another view, meaning it isn't in the view hierarchy.
Assuming you are doing this in a view controller, it might look something like:
[self.view addSubview: imgView];
(void)viewDidLoad {
[super viewDidLoad];
UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.layer.frame.size.width, self.view.layer.frame.size.height)];
imgView.image = [UIImage imageNamed:#"emptyCart.jpeg"];
imgView.backgroundColor = [UIColor whiteColor];
imgView.contentMode = UIViewContentModeCenter;
[self.view addSubview: imgView];
}
I had problem with passing the value NSSArray to NSString,
I got the answer:
//Display all images....
NSString *imgstring= [self.allimages objectAtIndex:indexPath.row];
cell.myimages.image=[UIImage imageNamed:imgstring]; //displaying Images in UIImageView..noproblem.
// Display all numbers...
cell.mylables.text=[NSString stringWithFormat:#"%#", [mysetobjectAtIndex:indexPath.row ]]; //showing results fine ArghyA..