CollectionViewController Thumbnail Builder

This is a start of multiple project I’ll be posting going farward, so prompt completion, and neat work will have higher priority in future project. Don't waste your time by bidding high. I can finish this project my self in 2-3 hours at most, the reason i'm posting this is i need to delegate future projects to the the winner, as i'm getting busy with more tedious jobs related to my project. so i'm hoping this will be an ongoing work. Here is the project info: Need a Collectionviewcontroller that will be added to an existing iPad app 1) I drafted a starter project on github using objective C, however feel free to convert it to swift in the deliveries. 2) the Collectionviewconroller will be supplied with an NSArray of images. All images are square size, and all images are loaded from disk (no network connectivity needed). images are fairly small size, so no need to worry about performance at this point 3) The collection view has a frozen header (see project demo) 4) All images are square size ratio. 5) On Load a) When presented it should display the images supplied as ordered in the array. They are scrollable as much as the array size. b) the header of the collectionviewcontroller shows four empty boxes where the generated images will lay down as the user start selecting images. c) We will call these boxes, box A (256x256), Box B(½ - ½), Box C (1/3 – 1/3 – 1/3), Box D ( ¼ - ¼ - ¼ - ¼ ) 6) On selecting any image (e.g. image 1) (first selection). a) it should show selection in the collection view controller with a checkmark or highlighted border. b) Image1 should show in box A c) In Box B: image 1 should be cropped half of its width (from the center) and placed on the first half of box B d) In Box C: image 1 should be cropped 1/3 of it’s width and placed in the first 1/3 of box C e) In Box D: image 1 should be cropped half of its width and ½ of it’s hight and placed on the first quarter of Box D 7) On selecting any second image (e.g. image 2) (second selection a) Box A: image 2 should replace the image of Box A b) Box B: image 2 should replace first ½ of box B (cropped like image 1) and the second half of box b should have the ½ of image 1 (now it’s in the second half instead of the first half) c) Box C: image 3 should replace the first 1/3 (cropped like image 1) and the second 1/3 of box C should have the 1/3 of image 1 (now it’s the second 1/3 instead of the first 1/3). d) Box D: image 1 (1/2x1/2) should occupy the second quarter of Box d and image 2 should now occupy the first quarter. Image 2 should occupy the first quarter (cropped ½ width ½ height) 8) On selecting third and fourth the cycle should go on to infinity: a) so for example, box 3 on selecting the third image (image 3) it should be in the first 1/3, image 2 should be in the second 1/3 image 3 should be in the 3rd 1/3. b) On selecting the 4th image, for box 3 image 4 should now be in the frist 1/3, image 3 in the 2nd 1/3 image 2 should be in the 3rd 1/3 and image 4 should be pushed out (queue model) and the box is showing the latest 3. 9) For Box A,B,C,D, they are selectable only if they are fully occupied e.g. a) Box A is selectable if it has an image b) Box B is selected if both halves are electable. 10) On selecting any of the completed boxes (A or B or C or D) the generated image should be provided in a block with callback. Code should be modularized, e.g. a class for cropping any image based to 1/3 or 1/2 of it's width another class to generate a steched image from 2-3 images provided in its constructor Thanks for your time.