Partially Convert the image in to black & white effect

Question

I have one image to which i want to give effect of black & white but only in some portion.For example. When the goal balance is at 0 dollars the image is 100% gray. The image colour will increase in the same percentage as the current balance of the savings goal. For example, if the savings total is $15000 but the savings balance is $7500, then only 50% of the image will be in colour and the other 50% will be gray. I know how to completely convert black & white image but don't know how to partially Convert the image into black & white shade.

score 5 · Answer 1 · edited May 23 '17 at 12:13

5

Something simple would be to create a copy of the image, crop it based on the percentage, convert that to black and white, and overlay it on the other image

link for how to crop an image

edited May 23 '17 at 12:13

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answered Jul 23 '12 at 10:33

wattson12

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Is there any reference link with you? – Nishith Shah Jul 23 '12 at 10:36
@wattson12 thanks but i don't want that half image will b&w n half will not I want that Whole image will have effect of partially black & white..... – Aakil Ladhani Jul 23 '12 at 11:15
@aakilladhani i dont understand what you mean, how can you have the whole image be partially black and white? you could create a black and white version and overlay it with varying alpha values? – wattson12 Jul 23 '12 at 11:30

score 0 · Answer 2 · answered Jul 23 '12 at 11:52

You want to use Core Image. Essentially you will use your current image as the input to the core image filter, employ a black and white filter, and control the filter so that the image can go from completely color to completely B&W.

So find the Core Image info on the developer site, and then look at the 100 or so filters Apple provides - I'm pretty sure one of them already does what you want.

Partially Convert the image in to black & white effect

2 Answers2