I have a UIimageView and I need to give some perspective to the image. Maybe by modifying the vertex of the image...
How can I do that?
A UIImageView is just a kind of UIView, so you can use the answer given in UIView perspective transform.
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I hope that makes sense. I'll try to explain it.
I have a UIImageView on screen, and am wondering how I can take the area after "drawing" on it with a finger, and remove that section from the UImage, or, create a separate UIImage from the selection.
I'm not looking for code (unless you have it =] ), just an idea of how to go about doing it. If you have tips, I'd be very grateful, thanks.
If I understand your question,
I think I would add a transparent UIView as a subview over the top of the UIImageView. And draw on that. Then you can remove/hide the subview when your done.
you need to create a UIGestureRecognizer with target and a action like -imageIsPressed, in this -imagePressed method you can call something to make the image disappear. I would suggest placing the UIImage into a UIImageView and calling imageview.hidden = YES; to hide the image, and set it back to "NO" once its not held by the finger.
You'd need to implement something that captures the area the user 'selected' (maybe be creating a CGPath. Then you create a CALayer of the size of the imageView. In it you create, draw and fill the captured path with some arbitrary color while leaving the rest transparent. Finally you apply your generated CALayer as a mask to the UIImageView:
imageView.layer.mask = maskLayer;
Hope that gets you started.
For more info on how to draw that custom CALayer pls refer to Quartz Programming Guide
So basically you want to implement freehand erasing of an image? You will need to use core graphics and the various CGContext methods (with blend mode set to clear) to achieve this. There are two approaches, but both start with drawing your image as the first part of drawRect, and then
1) Store your strokes in an array, and stroke all of them over top of the image.
2) Stroke one stroke over the image and then store the resulting image into a UIImage. Use this UIImage as the next image that you draw in drawRect. This one is difficult for undo/redo functionality.
I recently implemented this myself and made the source available here. Basically I used the same methods described here with this change when setting up the graphics context:
CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeClear);
I have an imageview in my xib file. I have to create a reflection view in other UIimageview. So I have taken one UIimageview to place its reflection. it is around half of original image view.
Can anyone suggest me best way to do it. I have tried a lot of examples but not satisfied with any.
Any help would be appreciated.
You may use a CALayer to do this (it would be more efficient than having a separate UIImageView).
Create a CALayer, add the image to it, set its transform property to scale(1,-1), and finally set its maskLayer to a CAGradientLayer that will go from opaque to transparent.
You try this :
http://www.iphonedevsdk.com/forum/iphone-sdk-tutorials/88208-uiimage-reflection-tutorial.html
I've got a UIScrollView whose zoom behavior I want to confine to the horizontal axis. I've accomplished that through using a custom UIView as the viewForZoomingInScrollView: and overriding setTransform:. So far so good – the view only zooms horizontally.
One catch: The container view includes some stretchable UIImage instances in UIImageViews. Obviously, with the transform in effect, the images distort.
What's the best bet for either redrawing the view so that the images aren't distorted, or, zooming the view in such a way as to not require transforms in the first place?
Thanks for any help you can offer.
You sure way of achieving this is to make your UIImageView into a custom UIView, and have its drawRect: code do the right thing: draw both stretched and unstretched elements.
How do I animate a UIImageView from UITableview with the flying effect?
Without knowing what you mean by the 'flying effect', pretty much any animation is possible using CoreAnimation.
Grab the UIImageView instance's layer and animate it as you wish.
Info on CoreAnimation can be found here.
set a UIImageView.image property to a UIImage is unable add the image to the view,however if i set the imageview frame property,it works.can anyone tell me how it's happen?
and what will happen when i apply the UIImage instance method[drawInRect:] redraw the image frame which is larger than the view frame?i have tried but nothing happen,and what is this function doing actual?
Generally, how it works is, you add an Image to a UIImageView and then add the UIImageView to a UIView to display it on the screen. You can do this programmatically, or using Interface Builder. Optionally, you can create a CGRect (based on a frame, if you like), use this as the bounds for the UIImageView (or you can frame the UIView). There are several ways to do what you want to do.
It's hard to tell without seeing your code. It could be a number of things. You could be inserting the view with the image behind the currentView? You may not be retaining the UIImageView. We can't read minds here necessarily, (sometimes we do). But you'll need to be more helpful if you want a solid answer.
Or just take a look at this:
UIImageView Docs