<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> </head> <body bgcolor="#ffffff" text="#000000"> How did you handle the alpha channel in (for example) gif images?     ExceptionInfo *exception;     Image    *image;     ImageInfo *image_info;     long x, y;     const PixelPacket *p;     QuantizeInfo *qinfo;     unsigned char *q;     unsigned char *imgbuf;     /*      * Initialize the image info structure and read an image.      */     MagickCoreGenesis(*argv,MagickTrue);     exception  = AcquireExceptionInfo();     image_info = CloneImageInfo((ImageInfo *) NULL);     (void) strcpy(image_info->filename,argv[1]);     image = ReadImage(image_info,exception);     if (exception->severity != UndefinedException)         CatchException(exception);     if (image == (Image *) NULL)         exit(1);     printf("rows = %ld, columns= %ld\n", image->rows, image->columns);    imgbuf = (unsigned char *)malloc(image->rows*image->columns*sizeof(char)*4);     q = imgbuf;     for(y=0; y < (long) image->rows; y++)     {         p = GetVirtualPixels(image, 0, y, image->columns, 1, exception);         if( p == (const PixelPacket *)NULL )             break;         for( x = 0; x < (long) image->columns; x++)         {             *q = ScaleQuantumToChar(p->blue);             q++;             *q = ScaleQuantumToChar(p->green);             q++;             *q = ScaleQuantumToChar(p->red);             q++;             *q = ScaleQuantumToChar(p->opacity);             q++;             p++;         }     } Is this the right way? Juan Aranda Thomas Stover wrote: <blockquote cite="mid:4989F21F.1040805@wsinnovations.com" type="cite"> <pre wrap="">A similar question came up on the gtk list the other day. Since you are looking for a way to do it without using an additional library, this is not your answer. However, I have been recommending people try ImageMagick <a class="moz-txt-link-freetext" href="http://www.imagemagick.org/script/index.php">http://www.imagemagick.org/script/index.php</a> for "non png" file formats and misc raster operations such as resize as a supplement to cairo. If you want my demo I can post it here. Out of curiosity, what are your reasons for not wanting another library? I have seen allot of aversion to mixing libraries lately. As long as licenses and technical details work out, to me that's how you bring some real alchemy to the table. </pre> <blockquote type="cite"> <pre wrap="">From: Tor Lillqvist <a class="moz-txt-link-rfc2396E" href="mailto:tml@iki.fi"><tml@iki.fi></a> Subject: Re: [cairo] how to import .BMP without other libs(GTK+ etc)? </pre> <blockquote type="cite"> <pre wrap="">we could do it with GTK+. However, is there some other way to import BMP or dib in cairo without the suppot of other libs? </pre> </blockquote> <pre wrap="">Not as far as I can see. </pre> <blockquote type="cite"> <pre wrap="">I had tried to do it whit cairo_image_surface_create_for_data, but failed. I could not see the right image. </pre> </blockquote> <pre wrap="">Are you sure that the .bmp file you are reading actually is in a (sub)format your code can handle? Didn't debugging (or adding printouts...) tell you anything? There must be a lot of sample code that reads .bmp out there, compare to the code of those... I know of io-bmp.c in gtk+/gdk-pixbuf and GIMP's bmp-read.c. A "throwaway" program I wrote to dump the contents of a .bmp file is at <a class="moz-txt-link-freetext" href="http://pastebin.com/m6e96721e">http://pastebin.com/m6e96721e</a> . Unfortunately it compiles as such only on Windows. --tml </pre> </blockquote> <pre wrap=""> _______________________________________________ cairo mailing list <a class="moz-txt-link-abbreviated" href="mailto:cairo@cairographics.org">cairo@cairographics.org</a> <a class="moz-txt-link-freetext" href="http://lists.cairographics.org/mailman/listinfo/cairo">http://lists.cairographics.org/mailman/listinfo/cairo</a> </pre> </blockquote> </body> </html>