What i ultimately would LOVE to do is having my scroll view contents scrolling (in the scroll view control), and have a static background (a wallpaper image).
I've tried a combination of things, none of which really yields what im looking for, not even close really.
Has anybody attempted this before?
This is actually very easy, a UIScrollView inherits from a UIView so you just need to set the backgroundColor property:
aScrollView.backgroundColor = [UIColor clearColor];
The above line of code sets the background to transparent so you can see through to whatever you want to put behind. Note also that you should do the same thing to the sub-views that you put inside the scroll-view - those views should also have a transparent background colour.
If you want a static image, use a pattern as in the line of code below. This can be a texture image smaller than the screen that will be repeated/tiled, or a full-screen image so you don't see any repeats.
aScrollView.backgroundColor = [UIColor colorWithPatternImage:anImage];
For those not having clear answer to this. It goes:
put an dummy holder imageview to the mainview and set it to the desired background image or set its backcolor as pattern, then inside this view put the scrollview and set its background to transparent.
Then you get the desired effect as with Safari on iPad for example on page scroll.
This is a code for Monotouch, but is straightforward to understand.
this.View.BackgroundColor = UIColor.FromPatternImage (UIImage.FromFile ("Images/About-bg0.jpg"));
scrollView = new UIScrollView (new RectangleF (0, 0, 320, 450));
scrollView.ContentSize = new SizeF (320, 640 + 508 + 1000);
//scrollView.BackgroundColor = UIColor.FromPatternImage (UIImage.FromFile ("Images/About-bg0.jpg"));
scrollView.BackgroundColor = UIColor.Clear;
After some quick googleing I found two links that will help you:
Google Groups discussion on this question
Blog post on how to do this.
Have you tried this,
self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"content.png"]];
This one worked for me...
self.scrollView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"tileableImage.png"]];
Related
Hello I am trying to resize a UIImage, but even though I'm not getting any errors it is not working.
hers the code of .h file
IBOutlet UIImageView *Fish;
heres the code of .m file
Fish.frame = CGRectMake(0, 0, 300, 293);
What am I doing wrong?
Thanks for any help
The image is probably not resizing because you are just resizing the image view. Make sure in your storyboard that you make the image view (Fish), have the move ScaleToFill. I can't do screenshot due to reputation ( sorry :( )
Alternately, if your goal is not to resize the image view but to resize the image it is holding, you can do this:
UIImage *image = Fish.image;
UIImage *image = YourImageView.image;
UIImage *tempImage = nil;
CGSize targetSize = CGSizeMake(80,60);
UIGraphicsBeginImageContext(targetSize);
CGRect thumbnailRect = CGRectMake(0, 0, 0, 0);
thumbnailRect.origin = CGPointMake(0.0,0.0);
thumbnailRect.size.width = targetSize.width;
thumbnailRect.size.height = targetSize.height;
[image drawInRect:thumbnailRect];
tempImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
YourImageView.image = tempImage;
and you would set thumbnailRect to whatever size you want.
Hope this helps! Please search Nerdy Lime on the app store to find all of my apps! Thanks!
I bet your outlet is not hooked up. In your "viewDidLoad" method, try doing this:
if(Fish)
{
Fish.frame = CGRectMake(0, 0, 300, 293);
} else {
NSLog(#"Fish is null; why did I forget to connect the outlet in my storyboard or xib?");
}
And this isn't the best way to resize your UIImageView. If you're using regular springs & struts, you can grow an outlet by clicking the springs & struts to grow based on the superview's size, e.g.:
And if you're doing AutoLayout, there's a different thing you can do (basically pin your view to all four sides of the superview).
Here is how I do it:
1) select the outlet / object you want to add constraints to (in your case, it'll be the fish image view)
2) see the segmented control at the bottom of the Interface Builder window? Click on the second one and you'll see a popover view open up with a list of possible constraints to add.
3) In my example, I'm adding constraints in my ImageView to always be 10 pixels from each edge of the superview (note the four "10"s and solid red lines meaning I'm adding four constraints).
AutoLayout is a pain to get accustomed to (and I'm still learning it myself), but I suspect that once one gets the hang of it, it'll be a powerful new tool especially as Apple brings in additional iOS screen sizes in the very near future.
In my app I use IKImageBrowserView with background. If wantsLayer NO - all fine and IKImageBrowserView look like nice. But if I enabled wantsLayer (in parent view) the background in IKImageBrowserView is corrupt. (Sorry English is not my native language and I can't find the correct word).
If I understand correctly, problem in this fragment. But I can't see where.
NSRect visibleRect = [owner visibleRect];
NSRect bounds = [owner bounds];
CGImageRef image = NULL;
NSString *path = [[NSBundle mainBundle] pathForResource:[#"metal_background.tif" stringByDeletingPathExtension] ofType:[#"metal_background.tif" pathExtension]];
if (!path) {
return;
}
CGImageSourceRef imageSource = CGImageSourceCreateWithURL((__bridge CFURLRef)[NSURL fileURLWithPath:path], NULL);
if (!imageSource) {
return;
}
image = CGImageSourceCreateImageAtIndex(imageSource, 0, NULL);
if (!image) {
CFRelease(imageSource);
return;
}
float width = (float) CGImageGetWidth(image);
float height = (float) CGImageGetHeight(image);
//compute coordinates to fill the view
float left, top, right, bottom;
top = bounds.size.height - NSMaxY(visibleRect);
top = fmod(top, height);
top = height - top;
right = NSMaxX(visibleRect);
bottom = -height;
// tile the image and take in account the offset to 'emulate' a scrolling background
for (top = visibleRect.size.height-top; top>bottom; top -= height){
for(left=0; left<right; left+=width){
CGContextDrawImage(context, CGRectMake(left, top, width, height), image);
}
}
CFRelease(imageSource);
CFRelease(image);
Image with problem
Image without problem
Thanks
I tried using IKImageView a few weeks ago and ran in to a number if problems. It's a nice class but it doesn't seem to have been updated in a long time. I doesn't support retina screen and, as you point out goes crazy when you add a layer.
I wanted to do some custom drawing with CALayer over the top of an image. The first thing I tried was to add a layer to the image view, which gave me problems. The solution I went for want to add a custom NSView subview to the image view, add auto layout constraints so that it always the same size, then add a layer hosting view to the subview. This worked fine, so move your drawing code to a custom subview and it should work.
IKImageView
LayerHostingView (<--- add CALayer here)
I ran in to this distorted background image problem as well and it turned out to be that I had set up the CALayer for the background incorrectly. I suspect that you are misunderstanding the cause to be setting wantsLayer to false because when that is set the layer does not immediately redraw new layers that you set.
I reached this conclusion as if I set up the layer correctly, then set wantsLayer false immediately before setting a bad CALayer in the next line of code I see the correct, undistorted image first and only when I scroll (and it redraws) do I see the buggy effects in your screenshot. However if I set wantsLayer true at the same point in code I see the buggy graphics immediately when the browser loads, without having to redraw first.
You can move the wantsLayer false statement further down your code to find the line that's breaking it, it'll be where the layer is reset/updated somewhere.
I need to make a simple scroll view in xcode with width of 280 and height of 80 and with images inside thats scrolls horizontally. i want to make this programmatically.
I assume you mean the UIScrollview, which has a guide written by apple found here:
http://developer.apple.com/library/ios/#documentation/uikit/reference/UIScrollView_Class/Reference/UIScrollView.html
A guide that I personally used was this one:
http://idevzilla.com/2010/09/16/uiscrollview-a-really-simple-tutorial/
I'll take you through the quick basics of adding the scrollview to your view and adding images to it.
I'm guessing you're new to Objective C, so I'll give you a quick guide. Firstly, you'll want to make a UIScrollView object. This is done by declaring the following:
UIScrollView *aScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake (0,0,320,250)];
You'll notice I set the frame. The first two numbers of CGRectMake give you the x and y origin of the point while the last two numbers are for how wide and tall you want your object to be.
Afterwards, you'll want to add images to it. You'll need a UIImageview.
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, 250)];
Note that I positioned the image at 0,0, giving it a height of a 250 and a width of 320. This ensures that it fills entire scrollview's initial view.
imageView.image = [UIImage imageNamed:#"foo.png"];
You'll attach an image to the imageView. But wait, there's more. So far you've created these objects but have not yet associated them with the view. So if we are in a ViewController class (you'll have to look up what that is), the ViewController contains a view. We can attach our objects to the view.
[aScrollView addSubview:imageView]; // Adds the image to the scrollview
[self.view addSubview:aScrollView]; // Adds the scrollview to the view.
If you want to add more images, you have to add them at different x origins. So our first added image was at 0,0. Our next added image should be at 320,0 (because the first image took up 320 pixels width).
UIImageView *secondImageView = [[UIImageView alloc] initWithFrame:CGRectMake(320, 0, 320, 250)];
secondImageView.image = [UIImage imageNamed:#"bar.png"];
[aScrollView addSubview:secondImageView];
There are a number of options for scrollview that you will want to explore. The ones I found useful were:
aScrollView.delegate = self; // For gesture callbacks
self.pagingEnabled = TRUE; // For one-at-a-time flick scrolling
self.showsHorizontalScrollIndicator = NO; // Cleaner look for some apps.
self.alwaysBounceHorizontal = TRUE; // Look it up.
I'm attempting to use the new [UINavigationBar appearance] functionality in iOS5 to add a logo image to the UINavigationBars in my application. Primarily, I'd like to keep the default gradient, but center a transparent png in the NavBar. The logo image is roughly 120 pixels wide (240 pixels#2x).
I have first attempted this by setting the background image. The default behavior for setBackgroundImage:forBarMetrics: appears to be to tile the image, and all transparent parts show the default navbar background color, black. I can also set the background color via the appearance modifier, and get a flat color background, but I'd really like to get the original gradient behavior without maintaining a separate image resource for it. It also makes it easier to adjust in code, since I can adjust the tint there, rather than re-generating a new image if I decide to change it.
What I'm trying to use:
UIImage *logoImage = [UIImage imageNamed:#"logoImage"];
[[UINavigationBar appearance] setBackgroundImage:logoImage forBarMetrics:UIBarMetricsDefault];
You can do this two ways. If you want to always have the image in the navigation bar, then create an image view and set it as a subview of the navigation bar:
[self setLogoImageView:[[UIImageView alloc] init]];
[logoImageView setImage:[UIImage imageNamed:#"logo.png"]];
[logoImageView setContentMode:UIViewContentModeScaleAspectFit];
CGRect navFrame = [[navController navigationBar] frame];
float imageViewHeight = navFrame.size.height - 9;
float x_pos = navFrame.origin.x + navFrame.size.width/2 - 111/2;
float y_pos = navFrame.size.height/2 - imageViewHeight/2.0;
CGRect logoFrame = CGRectMake(x_pos, y_pos, 111, imageViewHeight);
[logoImageView setFrame:logoFrame];
[[[self navigationController] navigationBar] addSubview:logoImageView];
If you only want to display the logo in a certain view, then set the view's navigation item:
[logoImageView setAutoresizingMask:UIViewAutoresizingFlexibleHeight];
[[self navigationItem] setTitleView:logoImageView];
I am wondering if there is a way to do this using Core Animation. Specifically, I am adding a sub-layer to a layer-backed custom NSView and setting its delegate to another custom NSView. That class's drawInRect method draws a single CGPath:
- (void)drawInRect:(CGRect)rect inContext:(CGContextRef)context
{
CGContextSaveGState(context);
CGContextSetLineWidth(context, 12);
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, 0, 0);
CGPathAddLineToPoint(path, NULL, rect.size.width, rect.size.height);
CGContextBeginPath(context);
CGContextAddPath(context, path);
CGContextStrokePath(context);
CGContextRestoreGState(context);
}
My desired effect would be to animate the drawing of this line. That is, I'd like for the line to actually "stretch" in an animated way. It seems like there would be a simple way to do this using Core Animation, but I haven't been able to come across any.
Do you have any suggestions as to how I could accomplish this goal?
I found this animated paths example and wanted to share it for anyone else looking for how to do this with some code examples.
You will be using CAShapeLayer's strokeStart and strokeEnd which requires sdk 4.2, so if you are looking to support older iOS SDKs unfortunately this isn't what you want.
The really nice thing about these properties is that they are animatable. By animating strokeEnd from 0.0 to 1.0 over a duration of a few seconds, we can easily display the path as it is being drawn:
CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:#"strokeEnd"];
pathAnimation.duration = 10.0;
pathAnimation.fromValue = [NSNumber numberWithFloat:0.0f];
pathAnimation.toValue = [NSNumber numberWithFloat:1.0f];
[self.pathLayer addAnimation:pathAnimation forKey:#"strokeEndAnimation"];
Finally, add a second layer containing the image of a pen and use a
CAKeyframeAnimation to animate it along the path with the same speed
to make the illusion perfect:
CAKeyframeAnimation *penAnimation = [CAKeyframeAnimation animationWithKeyPath:#"position"];
penAnimation.duration = 10.0;
penAnimation.path = self.pathLayer.path;
penAnimation.calculationMode = kCAAnimationPaced;
[self.penLayer addAnimation:penAnimation forKey:#"penAnimation"];
Which the source can be viewed here and a demo video here. Read the creators blog for more information.
Sure—don't draw the line yourself. Add a 12-pixel-high sublayer with a flat background color, starting with a zero-width frame and animating out to your view's width. If you need the ends to be rounded, set the layer's cornerRadius to half its height.