I couldn't find anything on how you can center the 'image' when you use (maybe you can't):
[self setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:#"background"]]];
Setting my [self setContentMode:UIContentModeCenter]; doesnt help.
Do I have to manually draw the image (either in drawRect or set the content of the CALayer? Which one if preferable?
I think you're on the wrong path here: you create a UIColor from a pattern (pattern already implies this is a repeating image). All in all- you can't have your pattern not repeat and centered.
If you just want simple image as background of your UIView, just add it as a subview and center it.
UIImage* img = [UIImage imageNamed:#"yourfile.png"];
UIImageView* imgView = [[UIImageView alloc]initWithImage: img];
[yourUIView addSubview: imgView];
imgView.center = CGPointMake(yourUIView.frame.size.width/2, yourUIView.frame.size.height/2);
Now - add more subviews to your "yourUIView" view and they'll show on top of the image - thus the image becoming the background.
So... no need to draw anything yourself.
Related
I'm working on a sort of drawing app using objective-c, and for one of my UIViews, I want there to be a background image to it. However, I want this background image on the actual UIView, not a separate UIImageView. I did that using this:
self.tempDrawImage.image = [UIImage imageNamed:#"image.jpg"];
In this code, tempDrawImage is a UIImageView I made programmatically, and after initializing it, I wrote this later in the code so that the drawings would appear on top of the image. I don't know if this is helpful, but I thought I'd include it anyway just in case it does help.
- (UIImageView *)tempDrawImage
{
if(!_tempDrawImage) _tempDrawImage = [UIImageView new];
return _tempDrawImage;
}
- (void)drawRect:(CGRect)rect
{
UIGraphicsGetCurrentContext();
[self.tempDrawImage.image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
}
Now, I'm struggling to make the image that I set to image.jpg in the beginning aspect fit. How could I do that?
Try this
self.tempDrawImage.contentMode = UIViewContentModeScaleAspectFit;
You can use UIViewContentModeScaleAspectFit
self.tempDrawImage.contentMode = UIViewContentModeScaleAspectFit;
Can anyone help me understand how I apply a background image object to a UIView please?
I have created a background image which is a blurred version of a background and I would like to apply it to be the background of a uiView in the foreground which would ideally mask the background image.
I have the following code so far -
_blurImage = [source stackBlur:50];
[_HPBlurView.backgroundColor = [UIColor colorWithPatternImage:[_blurImage]]];
I would like to apply the image object(_blurImage) to be the background image of _hpBlurView but i'm struggling to get it working!
At first glance, you are using too many brackets. Here is a working version of your code :
_burImage = [source stackBlur:50];
_HPBlurImage.backgroundColor = [UIColor colorWithPatternImage:_blurImage];
I can't see what stackBlur:50 returns. So start from the beginning. colorWithPatternImag takes UIImage as a parameter. So Start by adding a picture, any picture, to your application. Lets imagine that the image is called image.png. This is one way to do it:
UIImage *image = [UIImage imageNamed:#"image.png"];
_HPBlurView.backgroundColor = [UIColor colorWithPatternImage:image];
This should help to get you going.
Create an image and add to the background.:
UIImage *image = [UIImage imageNamed:#"youimage"];
self.view.backgroundColor = [UIColor colorWithPatternImage:image];
It's that.
To make sure everything resizes properly, no matter rotation, device size and iOS version, I just set an UIImageView
//Create UIImageView
UIImageView *backgroundImageView = [[UIImageView alloc] initWithFrame:self.view.frame]; //or in your case you should use your _blurView
backgroundImageView.image = [UIImage imageNamed:#"image.png"];
//set it as a subview
[self.view addSubview:backgoundImageView]; //in your case, again, use _blurView
//just in case
[self.view sendSubviewToBack:backgroundImageView];
I am trying to set a UITableView background using the following method:
[self.tableView setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:#"backgroundImage.png"]]];
This works great for making the background scroll with the table. However, my background image fades into a solid color, so instead of the background repeating, I'd love for it to just scroll up and just fit to the screen height. Then I can set self.view's backgroundColor to be the solid color and it will look great.
Other options seem to be blitting a small image at the bottom, but this seems complicated and I didn't quite understand how to draw the background and blit using CGContext.
Can someone tell me how to do this?
I'm not sure whether this will work but you should try creating a resizeable UIImage for the background:
If you want the last line of pixels to repeat you would call the
- (UIImage *)resizableImageWithCapInsets:(UIEdgeInsets)capInsets resizingMode:(UIImageResizingMode)resizingMode
on your image ( [UIImage imageNamed:#"backgroundImage.png"] )
with edgeinsets: UIEdgeInsetsMake(backgroundImage.size.height-1,0,0,0)
and resizingMode: UIImageResizingModeStretch
the complete call would look like
UIImage* backgroundImage = [UIImage imageNamed:#"backgroundImage.png"];
UIImage* newBackgroundImage = [backgroundImage resizableImageWithCapInsets:UIEdgeInsetsMake(backgroundImage.size.height-1,0,0,0) resizingMode:UIImageResizingModeStretch];
And now you could try to use this image for the pattern creation:
[self.tableView setBackgroundColor:[UIColor colorWithPatternImage:newBackgroundImage]];
This worked for me:
UIImageView* bgImageView = [[UIImageView alloc] initWithFrame:self.tableView.frame];
bgImageView.image = [UIImage imageNamed:#"bg"];
bgImageView.contentMode = UIViewContentModeTop;
[self.tableView addSubview:bgImageView];
[self.tableView sendSubviewToBack:bgImageView];
In my case it worked fine. I didn't test it with a lot of cells which are reused. But it should work :D
I would like to obtain this effect (http://stackoverflow.com/questions/7023271/how-to-adjust-drop-shadow-dynamically-during-an-uiimageview-rotation) but from a more complex image than just a red square ! If the link ever gets broken, it's a about how to adjust drop shadow dynamically during an UIImageView rotation.
So I tried implementing something but I just can't get the shadow in a separate layer... Here is my code, very simple, but doesn't work:
// here is my code
- (void)viewDidLoad {
[super viewDidLoad];
testView = [[UIImageView alloc] initWithImage: [UIImage imageNamed:#"handNoShadow.png"]];
testViewShadow = [[UIView alloc] initWithFrame:testView.frame];
testViewShadow.layer.shadowPath = [[testView layer] shadowPath];
testViewShadow.layer.shadowOpacity = 1.0;
testViewShadow.layer.shadowOffset = CGSizeMake(10, 10);
testViewShadow.layer.shadowRadius = 5.0;
[self.view addSubview:testViewShadow];
[self.view addSubview:testView];
}
PS: i did #import
I do get an image but no shadow... =(
Any lead, help, code, link... is welcome !
Thanks
possible cause:
your testViewShadow.clipToBounds property is set to YES (should be NO)
your testViewShadow do the drawing of the shadow correctly but another UIView is on top and mask it. Check your Z order. Either the order in Storyboard/Nib file (or the order you added the subviews programmatically). Last in the list (or last one added) is on top. For my app I had to put the UIView that need a shadow last so that no other view mask it.
I have a custom class inheriting from UITableViewCell class that shows either an image (left to the title) or a generic dark-colored square if the image is not available). The following code shows a dark square on a light-colored cell background:
imageView = [[UIImageView alloc] initWithFrame:CGRectMake(11, 6, 40, 40)];
[imageView setBackgroundColor:kBackgroundGreyColour];
[cell.contentView addSubview:imageView];
However, instead of creating a custom subview in each table cell I would rather like to use the existing imageView property of the generic UITableViewCell class and modify it somehow to show the square as the code above does. This is what I am trying at this moment:
UIImageView* iv = [[UIImageView alloc] initWithFrame:CGRectMake(11, 6, 40, 40)];
[iv setBackgroundColor:[UIColor redColor]];
self.imageView.hidden = NO;
self.imageView.opaque = iv.opaque;
self.imageView.alpha = iv.alpha;
self.imageView.image = iv.image;
[self bringSubviewToFront:self.imageView];
[self.imageView setBackgroundColor:[UIColor redColor]];
I added all those lines to set as many of the existing UIImageView properties to the same values as the created UIImageView instance in the first code snippet, and yet the second code snippet doesn't show any dark square. It just doesn't show anything at all and the cell looks like there is just the light background and no image view visible. But I see that the imageView property is not nil so executing all those lines of code in the second snippet should show something?
However, as soon as I assign a new image to the imageView property (e.g. self.imageView.image = [[UIImage alloc] init...], the square shows the assigned image without problems.
Edit: Just a note that in the second case I am setting the frame of the imageView in layoutSubview function, e.g.:
-(void)layoutSubviews
{
[super layoutSubviews];
self.imageView.frame = CGRectMake(11, 6, 40, 40);
}
So my questions are:
1. Which properties of the existing imageView property I would need to set and to what values so that the code will show a square filled with a specific color (like the first snippet of code does)?
Is there a way of creating the UIImage programatically so that it shows only a background color without any image associated with it (and which I could use to set the imageView.image property to show that color).
Is it possible to replace the existing imageView property in a UITableViewCell class with a custom view without adding a custom subview (like the first code snippet did), so that I can show a placeholder UIView with a background color when the image is not available?
The reason why your code doesn't work, is as you guessed; Because when you set the background colour of an imageview, it doesn't create anything on the image property.
And, you've figured out that you can't directly set the imageview property of the cell either.
I'd say your best bet, is the former option; To create a UIImage programmatically.
Although, I'd highly suggest simply creating one in your favourite image editing software then including it in the bundle. It makes for easy replacement later, for when you may get a better image, and next to no code and effort required to replace.
But if you still wish to do it all programmatically, it's not as simple as you'd hope.
CGRect rect = CGRectMake(11, 6, 40, 40);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [kBackgroundGreyColour CGColor]);
CGContextFillRect(context, rect);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
self.imageview.image = image;
Should do the trick.
This defines the image size, creates a graphics context (think of it as a canvas), picks your grey colour to use, paints the canvas with it, then scans it into your computer into the small little size you wanted.
The little green imp does it all behind the screen (Sorry, too much Terry Pratchett).