688963954a
* docs: Use Light codeblocks theme * docs: Fix image align * fix pixels * fix: Adjust all images
73 lines
2.9 KiB
Plaintext
73 lines
2.9 KiB
Plaintext
---
|
|
id: skia-frame-processors
|
|
title: Drawing to a Frame (Skia)
|
|
sidebar_label: Drawing to a Frame (Skia)
|
|
---
|
|
|
|
import Tabs from '@theme/Tabs'
|
|
import TabItem from '@theme/TabItem'
|
|
import useBaseUrl from '@docusaurus/useBaseUrl'
|
|
|
|
<div class="image-container">
|
|
<svg xmlns="http://www.w3.org/2000/svg" width="283" height="535">
|
|
<image href={useBaseUrl("img/demo_drawing.mp4")} x="18" y="33" width="247" height="469" />
|
|
<image href={useBaseUrl("img/frame.png")} width="283" height="535" />
|
|
</svg>
|
|
</div>
|
|
|
|
## Skia Frame Processors
|
|
|
|
It is technically pretty difficult to draw onto a Camera Frame and have it rendered into the resulting photo or video in realtime, but I have built a working proof of concept of that using Metal/OpenGL and [Skia](https://skia.org) straight in VisionCamera.
|
|
|
|
This allows you to draw onto a Frame using [react-native-skia](https://shopify.github.io/react-native-skia/)'s easy to use JavaScript APIs:
|
|
|
|
```ts
|
|
const frameProcessor = useSkiaFrameProcessor((frame) => {
|
|
'worklet'
|
|
|
|
// Detect objects using GPU-accelerated ML API
|
|
const bananas = detectBananas()
|
|
|
|
// Draw banana outline using GPU-accelerated Skia drawing API
|
|
for (const banana of bananas) {
|
|
const rect = Skia.XYWHRect(banana.x,
|
|
banana.y,
|
|
banana.width,
|
|
banana.height)
|
|
const paint = Skia.Paint()
|
|
paint.setColor(Skia.Color('red'))
|
|
frame.drawRect(rect, paint)
|
|
}
|
|
}, [])
|
|
```
|
|
|
|
..or even apply color-filters in realtime:
|
|
|
|
```ts
|
|
const invertColorsFilter = Skia.RuntimeEffect.Make(`
|
|
uniform shader image;
|
|
half4 main(vec2 pos) {
|
|
vec4 color = image.eval(pos);
|
|
return vec4((1.0 - color).rgb, 1.0);
|
|
}
|
|
`)
|
|
const paint = Skia.Paint(invertColorsFilter)
|
|
|
|
const frameProcessor = useSkiaFrameProcessor((frame) => {
|
|
'worklet'
|
|
|
|
// Draw frame using Skia Shader to invert colors
|
|
frame.render(paint)
|
|
}, [])
|
|
```
|
|
|
|
## VisionCamera Skia Integration
|
|
|
|
While the Skia Integration was originally planned for V3, I decided to remove it again because VisionCamera got insanely complex with that code integrated (custom Metal/OpenGL rendering pipeline with intermediate steps and tons of build setup, and fully custom Skia Preview View) and I wanted to keep VisionCamera lean so other users aren't affected by build issues caused by Skia or those GPU APIs. See [PR #1740](https://github.com/mrousavy/react-native-vision-camera/pull/1740) for more information.
|
|
|
|
At my app development agency, [Margelo](https://margelo.io), we have worked a lot with 2D and 3D graphics and Camera realtime processing (see the Snapchat-style mask filter on our website for example - that is running in VisionCamera/React Native!), if you need this feature [reach out to us](https://margelo.io#contact) and we'll build a customized/tailored solution for your company! :)
|
|
|
|
<br />
|
|
|
|
#### 🚀 Next section: [Zooming](/docs/guides/zooming) (or [creating a Frame Processor Plugin](/docs/guides/frame-processors-plugins-overview))
|