ofImage - saveJpg (with compression settings)

feature requests
#1

Open Frameworks has always been able to save JPGs, but as its stands there is no control over JPG compression settings, which are by default set pretty low. This codes adds a second save method, saveJpg(string fileName, int quality) which allows you to explicitly set the compression of the image. For me the main reason for doing this is that full screen PNG files can be quite large and its easy enough to end up with 20gigs of png files if you have an app that captures every x seconds. With this I can save out very high quality JPG images with a minimum of filesize.

I have been using this for myself for a year or so now, but would love to see it get added to the OF core.

in ofImage.h:

  
  
		// file loading / saving  
		bool 				loadImage(string fileName);  
		void 				saveImage(string fileName);  
	 void                          saveJpg(string fileName, int quality);   
  
  
  
		bool				loadImageIntoPixels(string fileName, ofPixels &pix);  
		void				saveImageFromPixels(string fileName, ofPixels &pix);  
		void                saveImageFromPixelsJPG(string fileName, ofPixels &pix, int quality);

if ofImage.cpp:

  
void ofImage::saveJpg(string fileName, int quality){  
    saveImageFromPixelsJPG( fileName, myPixels, quality);  
}  
  
  
//---------------------------------------------------------------------------------------  
void  ofImage::saveImageFromPixelsJPG(string fileName, ofPixels &pix, int quality){  
  
    if(quality > 100) quality = 100;  
    else if(quality <= 0)quality = 1;  
  
	if (pix.bAllocated == false){  
		printf("error saving image - pixels aren't allocated \n");  
		return;  
	}  
  
	#ifdef TARGET_LITTLE_ENDIAN  
		if (pix.bytesPerPixel != 1) swapRgb(pix);  
	#endif  
  
	FIBITMAP * bmp	= getBmpFromPixels(pix);  
  
	#ifdef TARGET_LITTLE_ENDIAN  
		if (pix.bytesPerPixel != 1) swapRgb(pix);  
	#endif  
  
	fileName = ofToDataPath(fileName);  
	if (pix.bAllocated == true){  
		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());  
		}  
  
  
        //FIMD_COMMENTS;  
		if((fif == FIF_JPEG) && FreeImage_FIFSupportsReading(fif)) {  
			FreeImage_Save(fif, bmp, fileName.c_str(), quality);  
		}  
		else{  
             printf("saveJpg - requires you to save with .jpg extension - image not saved\n");  
             return;  
        }  
	}  
  
	if (bmp != NULL){  
		FreeImage_Unload(bmp);  
	}  
}