How do you create a 'blurred text' image effect in iOS?

Question

I want to create a text shaped blur effect to an image as shown below:

Another example:

I have found an answer on blurring a UILabel answer: How to blur UILabel text. But the effect is not correct.

So, How can I create a blurred text image effect that I can render into an image as a watermark in Swift?

Somebody help me! Thanks very much!

By the way, the answers about UIVisualEffectView is not correct. The effect using UIVisualEffectView is like:

Besides, I also want to apply this kind of blur effect into photo's watermark.

So, any help?

Do you need to save the watermarked image? If not check UIVisualEffectView. — kennytm, Mar 14 '17 at 09:02
Use UIVisaulEffectView. [How to use UIVisualEffectView?](http://stackoverflow.com/questions/24067719/how-to-use-uivisualeffectview) — Sakir Sherasiya, Mar 14 '17 at 09:11
Use UIVisaulEffectView. [How to use UIVisualEffectView?](http://stackoverflow.com/questions/24067719/how-to-use-uivisualeffectview) — Sakir Sherasiya, Mar 14 '17 at 09:16
check: http://stackoverflow.com/questions/30303090/how-to-blur-uilabel-text — Nitin Gohel, Mar 14 '17 at 09:21
UIVisualEffectView is not correct. And I want to save the watermarked image indeed. — Chris Forever, Mar 14 '17 at 10:40

score 0 · Answer 1 · edited May 23 '17 at 11:46

You're going to need a two stage approach to get the desired effect:

Generate a black and white image of the text (black background, white text). The standard string in Swift has a Draw method. There's another Answer that has more detail on this.
Pass this 'text' image and your source image into the CIMaskedVariableBlur filter from CoreImage.

Basically, your 'text' image will act as the mask for the blur filter. Where the mask is lighter, the blur is stronger, and where the mask is black, no blur is applied.

How do you create a 'blurred text' image effect in iOS?

1 Answers1