Zooming lens functionality over UIImage [duplicate] - iphone

This question already has an answer here:
How can i apply lens effect to my UIImage?
(1 answer)
Closed 9 years ago.
I am working on an application that has an image and I want a lens (circular shape) that I can move over the image and the area comes under the circular lens will zoom.
Please provide some idea. This functionality is implemented in the app named PimpleEraser in AppStore.

This is a great tutorial on exactly what you want, a sort of magnifying glass.

Related

Overlapping UIImage with another image [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
How to implement alpha gradient on a image?
I have 2 images below
With these 2 images I want to create following effect. Any technique you think to mask these images to create required effect.
You could use a gradient mask to create something like this, but you wouldn't get the gloss and shadows that you see in your final image:

Match some predefined pattern ispresent in the image captured from camera or not and if then found their coordinates [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Recognize Black patterns appearing on the four corners of the image ios using opencv or some other technique
I want to create a app like shotnote app(basically its camera feature).
It is a page scanning app that is used to scan special type of paper.
http://itunes.apple.com/us/app/shot-note/id411332997?mt=8
Refer first two screenshots
You can check the functionality what I am searching in the following video:-
http://www.youtube.com/watch?v=8F_1iu4pDkQ
In my app
The paper background will be white and the pattern will be in black.
What I want is when I take a image from camera then it should match with the pattern (image or mages) and if patterns are present in that captured image then image should be cropped like in the way so that the patterns should appear at the corners of the image.
Basically I need to detect that the patterns are present and after that I want their coordinates so that I can crop the image accordingly.
Patterns you can assume as rectangle or L shape .
I am surfing for this from the last two weeks and still struggling with it.
Please provide me some sample code or some suggestions which I should follow.
Any suggestions would be highly appreciated.
Thanks in advance.
If you know that the pattern is always undistorted (i.e. no or very littly perspective in the original image) template matching, e.g. with a normalised cross correlation will do the trick just fine.

How to implement eraser functionality in DrawingApp? [duplicate]

This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
How do I implement a soft eraser stroke in a CGBitmapContext
How can I erase UIBezierPath lines drawn on a transparent view above an image?
In my Drawing app I want to implement Eraser Functionality.
If I have a white Background I will be erase that with change the color to white.
But, do I do if I have to erase the drawing on Background with photo?
How can I do that?
I believe that there are many possible solutions. One of them:
you create two layers (two images). One for the background, another for the drawn stuff.
when you "erase" you draw something. This something must mask background and
masked result must be drawn on the "stuff" layer.
Also you can play with masks, with blending options — I think every one of this features will allow you to implement "eraser" functionality.

make an image move like a circle with a timer [duplicate]

This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
How to let a view rotate forever?
Hi everyone I would like to know if it is possible to move an image round in a circle with a timer. FOr example make it moves arround a circle with a timer that everytime it display a new position to the image. How can I do this please ? sorry for my english I'm french :/
make an anchorpoint for the image to rotate around? sorry you didnt provide alot of information....
This website covers exactly how anchor points work and how you can get an object to circle around that point http://www.qcmat.com/understanding-anchorpoint-in-cocos2d/

Draw an arc on circle [duplicate]

This question already has answers here:
Draw part of a circle
(8 answers)
Closed 9 years ago.
I am developing an application in which I have to show a filled arc on my circle which will indicate the selected time.
I have attached an image for specifying what I exactly want to ask:-
Please help me in how to draw arc on circle.
Any suggestions will be highly appreciated.
you need something like this