C++ ofPixels_::getNumChannels方法代码示例

void ofPixels_<PixelType>::copyFrom(const ofPixels_<PixelType> & mom){
	if(mom.isAllocated()) {
		allocate(mom.getWidth(), mom.getHeight(), mom.getNumChannels());
		memcpy(pixels, mom.getPixels(), mom.getWidth() * mom.getHeight() * mom.getBytesPerPixel());
	}
}

static void saveImage(ofPixels_<PixelType> & pix, ofBuffer & buffer, ofImageFormat format, ofImageQualityType qualityLevel) {
	//thanks to alvaro casinelli for the implementation

	ofInitFreeImage();

	if (pix.isAllocated() == false){
		ofLog(OF_LOG_ERROR,"error saving image - pixels aren't allocated");
		return;
	}

	if(format==OF_IMAGE_FORMAT_JPEG && pix.getNumChannels()==4){
		ofPixels pix3 = pix;
		pix3.setNumChannels(3);
		saveImage(pix3,buffer,format,qualityLevel);
		return;
	}

	#ifdef TARGET_LITTLE_ENDIAN
	if(sizeof(PixelType) == 1) {
		pix.swapRgb();
	}
	#endif

	FIBITMAP * bmp	= getBmpFromPixels(pix);

	#ifdef TARGET_LITTLE_ENDIAN
	if(sizeof(PixelType) == 1) {
		pix.swapRgb();
	}
	#endif

	if (bmp)  // bitmap successfully created
	{
		   // (b) open a memory stream to compress the image onto mem_buffer:
		   //
		   FIMEMORY *hmem = FreeImage_OpenMemory();
		   // (c) encode and save the image to the memory (on dib FIBITMAP image):
		   //
		   if(FREE_IMAGE_FORMAT(format) == FIF_JPEG) {
				int quality = JPEG_QUALITYSUPERB;
				switch(qualityLevel) {
					case OF_IMAGE_QUALITY_WORST: quality = JPEG_QUALITYBAD; break;
					case OF_IMAGE_QUALITY_LOW: quality = JPEG_QUALITYAVERAGE; break;
					case OF_IMAGE_QUALITY_MEDIUM: quality = JPEG_QUALITYNORMAL; break;
					case OF_IMAGE_QUALITY_HIGH: quality = JPEG_QUALITYGOOD; break;
					case OF_IMAGE_QUALITY_BEST: quality = JPEG_QUALITYSUPERB; break;
				}
				FreeImage_SaveToMemory(FIF_JPEG, bmp, hmem, quality);
		   }else{
				FreeImage_SaveToMemory((FREE_IMAGE_FORMAT)format, bmp, hmem);
		   }

		   /*

		  NOTE: at this point, hmem contains the entire data in memory stored in fif format. the
		  amount of space used by the memory is equal to file_size:
		  long file_size = FreeImage_TellMemory(hmem);
		  but can also be retrieved by FreeImage_AcquireMemory that retrieves both the
		  length of the buffer, and the buffer memory address.
		  */
			#ifdef TARGET_WIN32
		   	   DWORD size_in_bytes = 0;
			#else
		   	   uint32_t size_in_bytes = 0;
			#endif
		   // Save compressed data on mem_buffer
		   // note: FreeImage_AquireMemory allocates space for aux_mem_buffer):
		   //
		   unsigned char *mem_buffer = NULL;
		   if (!FreeImage_AcquireMemory(hmem, &mem_buffer, &size_in_bytes))
				   cout << "Error aquiring compressed image from memory" << endl;

		   /*
			  Now, before closing the memory stream, copy the content of mem_buffer
			  to an auxiliary buffer
		    */

		   buffer.set((char*)mem_buffer,size_in_bytes);

		   // Finally, close the FIBITMAP object, or we will get a memory leak:
		   FreeImage_Unload(bmp);

		   // Close the memory stream (otherwise we may get a memory leak).
		   FreeImage_CloseMemory(hmem);
	}
}

static bool saveImage(const ofPixels_<PixelType> & _pix, const std::filesystem::path& _fileName, ofImageQualityType qualityLevel) {
	ofInitFreeImage();
	if (_pix.isAllocated() == false){
		ofLogError("ofImage") << "saveImage(): couldn't save \"" << _fileName << "\", pixels are not allocated";
		return false;
	}

	ofFilePath::createEnclosingDirectory(_fileName);
	std::string fileName = ofToDataPath(_fileName);
	FREE_IMAGE_FORMAT fif = FIF_UNKNOWN;
	fif = FreeImage_GetFileType(fileName.c_str(), 0);
	if(fif == FIF_UNKNOWN) {
		// or guess via filename
		fif = FreeImage_GetFIFFromFilename(fileName.c_str());
	}
	if(fif==FIF_JPEG && (_pix.getNumChannels()==4 || _pix.getBitsPerChannel() > 8)){
		ofPixels pix3 = _pix;
		pix3.setNumChannels(3);
		return saveImage(pix3,_fileName,qualityLevel);
	}

	FIBITMAP * bmp = nullptr;
	#ifdef TARGET_LITTLE_ENDIAN
	if(sizeof(PixelType) == 1 && (_pix.getPixelFormat()==OF_PIXELS_RGB || _pix.getPixelFormat()==OF_PIXELS_RGBA)) {	// Make a local copy.
		ofPixels_<PixelType> pix = _pix;
		pix.swapRgb();
		bmp	= getBmpFromPixels(pix);
	}else{
	#endif

		bmp	= getBmpFromPixels(_pix);


	#ifdef TARGET_LITTLE_ENDIAN
	}
	#endif

	bool retValue = false;
	if((fif != FIF_UNKNOWN) && FreeImage_FIFSupportsReading(fif)) {
		if(fif == FIF_JPEG) {
			int quality = JPEG_QUALITYSUPERB;
			switch(qualityLevel) {
				case OF_IMAGE_QUALITY_WORST: quality = JPEG_QUALITYBAD; break;
				case OF_IMAGE_QUALITY_LOW: quality = JPEG_QUALITYAVERAGE; break;
				case OF_IMAGE_QUALITY_MEDIUM: quality = JPEG_QUALITYNORMAL; break;
				case OF_IMAGE_QUALITY_HIGH: quality = JPEG_QUALITYGOOD; break;
				case OF_IMAGE_QUALITY_BEST: quality = JPEG_QUALITYSUPERB; break;
			}
			retValue = FreeImage_Save(fif, bmp, fileName.c_str(), quality);
		} else {
			if(qualityLevel != OF_IMAGE_QUALITY_BEST) {
				ofLogWarning("ofImage") << "saveImage(): ofImageCompressionType only applies to JPEGs,"
					<< " ignoring value for \" "<< fileName << "\"";
			}

			if (fif == FIF_GIF) {
				FIBITMAP* convertedBmp;
				if(_pix.getImageType() == OF_IMAGE_COLOR_ALPHA) {
					// this just converts the image to grayscale so it can save something
					convertedBmp = FreeImage_ConvertTo8Bits(bmp);
				} else {
					// this will create a 256-color palette from the image
					convertedBmp = FreeImage_ColorQuantize(bmp, FIQ_NNQUANT);
				}
				retValue = FreeImage_Save(fif, convertedBmp, fileName.c_str());
				if (convertedBmp != nullptr){
					FreeImage_Unload(convertedBmp);
				}
			} else {
				retValue = FreeImage_Save(fif, bmp, fileName.c_str());
			}
		}
	}

	if (bmp != nullptr){
		FreeImage_Unload(bmp);
	}

	return retValue;
}