I have an NSImageView which contains an image. Is there a simple way to draw a border around just the image (which might be smaller than the NSImageView), and not the entire NSImageView?
[Answering my own question.]
On the off chance that someone comes cross this page looking to get something similar done, a simple way to do it is by using a wrapper view, and setting a border on the inner view.
Related
I'm trying to achieve a sort of dynamic UIView masking effect. Here is a sketch:
So as you can see, I'm trying to create a UIView that can effectively cut through an image to reveal the image behind it. I already know how to return an image with a mask statically, however I would like the "revealer" to be draggable (I'll use pan gesture) and live.
Does anyone have any ideas or starting points on how to achieve this? Thanks
(NOTE: My demo says White layer, but I'd actually like to show another image or photo).
masking an image is not that difficult.
This link shows the basics.
http://iosdevelopertips.com/cocoa/how-to-mask-an-image.html
But personally I think i would make 2 UIImage views and crop the content of the draggable UIView. I'm not sure but I would expect that clipping and panning the second image will be less computationally expensive then applying the mask and will get you a better frame rate.
So I would do: UIImageView of the full image. A UIView on top of it with a white and some transparency setting to make it look white, then a UIImageView with the image either places or cropped so that only the correct section is showing.
I've not much response so am adding some more info.
My buttons are not rectangular, nor organised in a grid so I need a way of creating what looks like a button (and shows that it has been pressed visually, as per a standard UIButton) but where the touchable area is different to the image area.
I am using a transparent PNG and that element works fine. I've added the buttons in Interface Builder and am wondering if that is the problem.
However, if I change imageEdgeInsets, it distorts the image display, which is obviously not what I want.
Bizarrely, if I increase the dimemsions of the button, it doesn't change the image, but if I decrease them it does.
I have tried different combinations of mode (scale to fill etc), but to no avail.
I am aware that there is an image and background image property, but in IB there is only one.
Essentially, I don't understand how the geometry works and the Apple documentation doesn't seem to help.
Surely, I can't be the only person to try to do this. Any help would be warmly welcomed.
Many thanks,
Chris.
Try setting the buttons setting to Aspect Fit. This will fill the button with your image so a smaller image than the button size would leave the space around the image.
Also set the button type to custom.
In the end, I stumbled across Ole Begemann's Non-rectangular buttons class. It just does what I need - to be able to create buttons where the touchable area follows the visible element of a non rectangular image.
#Helium3 - thanks - that allowed me to use a larger touch area, bit not a smaller one.
I'm creating an iphone application. I have this UIView whose content is clipped with a path. I want to add shading and/or shadow to it. What's the best way to do this? For shadow, I tried CGContextSetShadow() but it doesn't seem to have an effect (perhaps it's drawing outside the shown region?) . How about shading? I want it to appear along the path. What's the best way to go about it? Is it to create another narrow clip strip along the original clipping path (if it's possible to have two clip path... ) Or does this need to be done in another CALayer? I am not even sure what that is yet.
You can't add shadows to layers which are clipped or masked. The way I would do this is use two CALayers, one for the clipped content and place this inside another for the shadow which isn't clipped.
I want to implement dialog borders that scale to the size I require the dialog to be. Perhaps there is a better more conventional name for this sort of thing. If there is, if someone would edit the title, that'd be great.
Anyhow, I'd like to do this so I can have dialogs of any size without the visual artifacts that come with scaling border art to small, large, or wacky unproportional dimentions. I have a few ideas on how this is done, but am not sure which is better for iphone. I have a few questions.
1) Should I make a containing view object that basically overloads its drawRect method and draws the images where they should be at their appropriate scale when the method is called, or should I main a containing view object that simply contains 8 UIImageViews? I suspect the latter approach won't work if I need to actively scale the resulting dialog class like in an animation.
1b) If overloading drawRect is the way to go, does someone have some sample code or a link to an example that demonstrates drawing an image directly from drawRect()?
2) Is it generally better to create
a) a 3 x 3 image where the segments are in their appropriate 1x1 grid of the image? If so, is it simple to draw from a portion of this image onto my target view in drawRect (if the former assumption is correct that I should use drawRect)?
b) The pieces separately in 8 different files?
UPDATE:
To clarify, the idea is to take any customized border art and be able to stretch the 2nd, 4th, 6th, and 8th cell (in a 3x3-cell grid) to form a border of any size with just those assets. Stretching just a plain image would result in distortion of the corners, so I'd like to stretch those even numbered cells as needed and tack on the corners so there is no distortion. I'd seen this done before so thought it might be a standard thing and have a standard naming to it other than what I called it.
Anyhow, I was advised that adding 8 UIImageViews to a container would not be as efficient as drawing the UIImages on the fly in drawRect so took that approach using CGContextDrawImage() after applying the necessary transformations to the context to translate and scale the Y. Because this function draws from the bottom left corner of an image but onto a top-left origined UIView, the image is upside down without the Y axis invert. I noticed the suggestion to use UIImage functions like drawAtPoint works as well and similarly but for the invert since UIImage draws in the same orientation as UIViews. I will continue my implementation with the former and see how it goes, but one other question.
Would someone happen to know which of these approaches is more efficeint, faster, etc?
I'm not sure I follow, but here's my best shot at an answer...
Using drawRect: or adding individual UIImageViews to a parent view is entirely up to you. UIImageView gives you a bit of encapsulated functionality for free, but otherwise they are the same as far as appearances go.
If you do want to go the drawRect route, you just need to use UIImage's drawAtPoint: method. Do the math for where you want it to be, and draw it. You can calculate your points based on the parent view's dimensions.
As far as scaling, it's impossible to resize these images without scaling them, so I'd plan ahead and make your originals as large or larger than you ever expect to display them.
Hope that helps a little?
Cheers
If you want a border on a dialog box, assuming the box is a UIView (or subclass), then set the layer's border properties and let the system draw the border for you.
#import <QuartzCore/QuartzCore.h>
// ...
view.layer.borderWidth = 2;
view.layer.borderColor = [UIColor whiteColor].CGColor;
view.layer.cornerRadius = 0; // 0=square corners, >0 for rounded
I have a png image file that is partly opaque and partly transparent. I display it in a UIImageView as a mask of sorts over another UIImageView layered behind it (as a sibling subview of a common superview). It gives me perfect borders around something painted using a finger on the lower UIImageView in my stack of UIImageViews. Perhaps there are better ways to do this, but I am new-ish, and this is the best way I came up with thus far. None the less, my app is in the App Store and now I want to enhance it to provide more images to use as the mask of sorts over the finger painting. But I don't want to bloat my bundle size by adding more static mask images as I did for the initial implementation. Not to mention I don't want to spend lots of time in photoshop making 100 masks. I'd rather programmatically change the color of the mask, without affecting the clear portion in the middle, which is not a simple regtangle or circle, but rather a complex shape. So my question is this: How can I change the colored portion of my loaded image without affecting the clear color portion in the middle? Is there a reasonably easy way to do this? Essentially I want to do what is described in this post (How would I tint an image programmatically on the iPhone?) without affecting the clear portion of my image. Thanks for any insights.
Have a look at the Tinted Image sample project. Try out the different modes until you get the effect you want.