CoreImage | # # 效果展示 人物原图 截取280 * 280大小大图片。效果如下： 纯背景图片 | Computer Vision library

I'm trying to set the background color of a UIAlertController. The code I'm using appears to (almost) do that except it looks more like Tint than BackgroundColor. The corners are the color I'm setting it to but the main body of the alert looks more like it's tinted. My understanding is that the actual alert view is the last subview of the UIAlertController.

My code:

I am currently trying to write a function which takes an image and applies a 3x3 Matrix to filter the vertical edges. For that I am using CoreImage's CIConvolution3X3 and passing the matrix used to detect vertical edges in Sobels edge detection.

Here's the code:

I have written code to render text to a MTKView, but I have not found a way to modify the color of the text. Has anyone had success with this or can someone more familiar with CoreImage assist? Thank you.

Update: Answering the main question accoring to @FrankSchlegel - no, there is no way to check how system CIFilter's are working.

Is it possible to see how some of CIFilter default filters are implemented such as CIDissolveTransition or CISwipeTransition for example? I want to build some custom transition filters and want to see some Metal Shading Language examples if possible. Can't really find any examples of transition filters on the Internet done in MSL, only in regular Metal pipeline.

Update 1: Here is an example of a Fade filter I wish to port to MSL:

This is part of an ongoing attempt at teaching myself how to create a basic painting app in iOS, like MSPaint. I'm using SwiftUI and CoreImage to do this.

While I have my mind wrapped around the pixel manipulation in CoreImage (I've been looking at this), I'm not sure how to add a drag gesture to SwiftUI so that I can "paint".

With the drag gesture, I'd like to do this:

onBegin and onChanged:

• send the current x,y position of my finger to the function handling the CoreImage manipulation;
• receive and display the updated image;
• repeat until gesture ends.

So in other words, continuously update the image as my finger moves.

UPDATE: I've taken a look at what Asperi below responded with, and added .gesture below .onAppear. However, this results in a warning "Modifying state during view update, this will cause undefined behavior."

I was walking through this tutorial on custom CIFilter:

https://medium.com/@m_tuzer/using-metal-shading-language-for-custom-cikernels-metal-swift-7bc8e7e913e6

Everything works perfectly except that the coordinates of the sampler are not normalized. So, e.g a condition like this pos.y < 0.33 doesn’t work, and the kernel uses actual image coordinates.

Since the tutorial is old there probably has been changes in CIFilter that “broke” this code. I looked through the manual for CI kernels but could not find a way to get normalized coordinates of a sampler inside the kernel.

Here is the code of the kernel:

I want to make this custom CIFilter.

I have a swift struct:

I am making an app with KivyMD with python, now I want to make a quick documentation with Sphinx. But everytime I use "make html" on the command line I get the following error: