The problem is that I can’t understand how the “official” JPG->PGM convertitors work in terms of what value to assign to the final pixel (i guess, 0->255) starting from the classic RGB format. There is likely a gamma adjustment in the conversion those “official” tools are using.That is, it is not just a linear transform. … Read more
For Java 6 (and 5 too, I think): BufferedImage bufferedImage = new BufferedImage(image.getWidth(null), image.getHeight(null), BufferedImage.TYPE_INT_RGB); g = bufferedImage.createGraphics(); //Color.WHITE estes the background to white. You can use any other color g.drawImage(image, 0, 0, bufferedImage.getWidth(), bufferedImage.getHeight(), Color.WHITE, null);
PNG’s are pixel perfect (non-lossy), and require very little extra CPU energy to display. However, large PNGs may take longer to read from storage than more compressed image formats, and thus be slower to display. JPG’s are smaller to store, but lossy (amount depends on compression level), and to display them requires a much more … Read more
Bit too big for a comment, so I’ve added a new answer. The EndPage procedure (see page 441 of the PostScript Language Reference Manual) takes two additional parameters on the stack, a count of pages emitted so far, and a reason code. You can use the count of pages to do interesting things like duplexing, … Read more
XMP data is literally embedded into the image file so can extract it with PHP’s string-functions from the image file itself. The following demonstrates this procedure (I’m using SimpleXML but every other XML API or even simple and clever string parsing may give you equal results): $content = file_get_contents($image); $xmp_data_start = strpos($content, ‘<x:xmpmeta’); $xmp_data_end = … Read more
OK, after a lot of effort here’s the answer: int SaveJpeg(HBITMAP hBmp, LPCWSTR lpszFilename, ULONG uQuality) { ULONG *pBitmap = NULL; CLSID imageCLSID; EncoderParameters encoderParams; int iRes = 0; typedef Status (WINAPI *pGdipCreateBitmapFromHBITMAP)(HBITMAP, HPALETTE, ULONG**); pGdipCreateBitmapFromHBITMAP lGdipCreateBitmapFromHBITMAP; typedef Status (WINAPI *pGdipSaveImageToFile)(ULONG *, const WCHAR*, const CLSID*, const EncoderParameters*); pGdipSaveImageToFile lGdipSaveImageToFile; // load GdipCreateBitmapFromHBITMAP lGdipCreateBitmapFromHBITMAP = … Read more
You should be able to do something like this: using System.Drawing.Imaging; using System.Drawing; using System.IO; byte[] bitmap = GetYourImage(); using(Image image = Image.FromStream(new MemoryStream(bitmap))) { image.Save(“output.jpg”, ImageFormat.Jpeg); // Or Png } Look here for more info. Hopefully this helps.
You can view compress level using the identify tool in ImageMagick. Download and installation instructions can be found at the official website. After you install it, run the following command from the command line: identify -format ‘%Q’ yourimage.jpg This will return a value from 0 (low quality, small filesize) to 100 (high quality, large filesize). … Read more
JPG and JPEG stand both for an image format proposed and supported by the Joint Photographic Experts Group. The two terms have the same meaning and are interchangeable. To read on, check out Difference between JPG and JPEG. The reason for the different file extensions dates back to the early versions of Windows. The original … Read more
In response to Slee’s question above, this is the method I use: -(BOOL)dataIsValidJPEG:(NSData *)data { if (!data || data.length < 2) return NO; NSInteger totalBytes = data.length; const char *bytes = (const char*)[data bytes]; return (bytes[0] == (char)0xff && bytes[1] == (char)0xd8 && bytes[totalBytes-2] == (char)0xff && bytes[totalBytes-1] == (char)0xd9); }