react-native-vision-camera/ios/Skia Render Layer/SkImageHelpers.mm

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//
// CMSampleBuffer+toSkImage.m
// VisionCamera
//
// Created by Marc Rousavy on 23.11.22.
// Copyright © 2022 mrousavy. All rights reserved.
//
#import "SkImageHelpers.h"
#import <AVFoundation/AVFoundation.h>
#import <Metal/Metal.h>
#import <include/core/SkColorSpace.h>
#import <include/core/SkSurface.h>
#import <include/core/SkCanvas.h>
#import <include/core/SkImage.h>
#import <include/gpu/ganesh/SkImageGanesh.h>
#import <include/gpu/mtl/GrMtlTypes.h>
#import <include/gpu/GrRecordingContext.h>
#include <TargetConditionals.h>
#if TARGET_RT_BIG_ENDIAN
# define FourCC2Str(fourcc) (const char[]){*((char*)&fourcc), *(((char*)&fourcc)+1), *(((char*)&fourcc)+2), *(((char*)&fourcc)+3),0}
#else
# define FourCC2Str(fourcc) (const char[]){*(((char*)&fourcc)+3), *(((char*)&fourcc)+2), *(((char*)&fourcc)+1), *(((char*)&fourcc)+0),0}
#endif
CVMetalTextureCacheRef getTextureCache(GrRecordingContext* context) {
static CVMetalTextureCacheRef textureCache = nil;
if (textureCache == nil) {
// Create a new Texture Cache
auto result = CVMetalTextureCacheCreate(kCFAllocatorDefault,
nil,
MTLCreateSystemDefaultDevice(),
nil,
&textureCache);
if (result != kCVReturnSuccess || textureCache == nil) {
throw std::runtime_error("Failed to create Metal Texture Cache!");
}
}
return textureCache;
}
sk_sp<SkImage> SkImageHelpers::convertCMSampleBufferToSkImage(GrRecordingContext* context, CMSampleBufferRef sampleBuffer) {
auto pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
double width = CVPixelBufferGetWidth(pixelBuffer);
double height = CVPixelBufferGetHeight(pixelBuffer);
// Make sure the format is RGB (BGRA_8888)
auto format = CVPixelBufferGetPixelFormatType(pixelBuffer);
if (format != kCVPixelFormatType_32BGRA) {
auto fourCharCode = @(FourCC2Str(format));
auto error = std::string("VisionCamera: Frame has unknown Pixel Format (") + fourCharCode.UTF8String + std::string(") - cannot convert to SkImage!");
throw std::runtime_error(error);
}
auto textureCache = getTextureCache(context);
// Convert CMSampleBuffer* -> CVMetalTexture*
CVMetalTextureRef cvTexture;
CVMetalTextureCacheCreateTextureFromImage(kCFAllocatorDefault,
textureCache,
pixelBuffer,
nil,
MTLPixelFormatBGRA8Unorm,
width,
height,
0, // plane index
&cvTexture);
GrMtlTextureInfo textureInfo;
auto mtlTexture = CVMetalTextureGetTexture(cvTexture);
textureInfo.fTexture.retain((__bridge void*)mtlTexture);
// Wrap it in a GrBackendTexture
GrBackendTexture texture(width, height, GrMipmapped::kNo, textureInfo);
// Create an SkImage from the existing texture
auto image = SkImages::AdoptTextureFrom(context,
texture,
kTopLeft_GrSurfaceOrigin,
kBGRA_8888_SkColorType,
kOpaque_SkAlphaType,
SkColorSpace::MakeSRGB());
// Release the Texture wrapper (it will still be strong)
CFRelease(cvTexture);
return image;
}
sk_sp<SkImage> SkImageHelpers::convertMTLTextureToSkImage(GrRecordingContext* context, id<MTLTexture> texture) {
// Convert the rendered MTLTexture to an SkImage
GrMtlTextureInfo textureInfo;
textureInfo.fTexture.retain((__bridge void*)texture);
GrBackendTexture backendTexture(texture.width, texture.height, GrMipmapped::kNo, textureInfo);
auto image = SkImages::AdoptTextureFrom(context,
backendTexture,
kTopLeft_GrSurfaceOrigin,
kBGRA_8888_SkColorType,
kOpaque_SkAlphaType,
SkColorSpace::MakeSRGB());
return image;
}
SkRect SkImageHelpers::createCenterCropRect(SkRect sourceRect, SkRect destinationRect) {
SkSize src;
if (destinationRect.width() / destinationRect.height() > sourceRect.width() / sourceRect.height()) {
src = SkSize::Make(sourceRect.width(), (sourceRect.width() * destinationRect.height()) / destinationRect.width());
} else {
src = SkSize::Make((sourceRect.height() * destinationRect.width()) / destinationRect.height(), sourceRect.height());
}
return inscribe(src, sourceRect);
}
SkRect SkImageHelpers::inscribe(SkSize size, SkRect rect) {
auto halfWidthDelta = (rect.width() - size.width()) / 2.0;
auto halfHeightDelta = (rect.height() - size.height()) / 2.0;
return SkRect::MakeXYWH(rect.x() + halfWidthDelta,
rect.y() + halfHeightDelta,
size.width(),
size.height());
}