VB/WinAPI/Graphics, Converting a 24 bit bitmap

Converting a 24 bit bitmap

Author	Message
Adam Ioannide #1 / 3	Converting a 24 bit bitmap Can someone tell me how can I conver a 24 bit image to a 256 color bitmap or to a JPG file?
Sat, 17 Jul 2004 16:27:01 GMT

Mike D Sutto #2 / 3	Converting a 24 bit bitmap Quote: > Can someone tell me how can I conver a 24 bit image to > a 256 color bitmap or to a JPG file? To convert to an 8-bit bitmap requires more work than you may expect, mostly because you've got to find the best palette to represent the image (24-bit images aren't based on palette's where was <= 8-bit are). Various colour-space quantisation methods exist and you can find information about these if you do a search but be warned it's quite tricky. There is a VB implementation on www.vbaccelerator.com though if you don't fancy giving it a shot yourself. To save as a .JPG then you'll need to grab the IJL off www.Intel.com and you'll find a demonstration VB project in there that shows you how to convert a bitmap to JPEG. Hope this helps, Mike -- EDais -- - Microsoft Visual Basic MVP - WWW: Http://EDais.earlsoft.co.uk/
Sat, 17 Jul 2004 17:37:49 GMT

Stephen Leban #3 / 3	Converting a 24 bit bitmap The sample you pointed to at www.vbaccelerator.com works great Mike but there is a couple of typeo's/bugs in the source. A search on google will turn up the thread outlining the mistakes in the original source. I modified that code to try and increase the execution speed. See: http://www.lebans.com/pictureboxtogif.htm -- HTH Stephen Lebans http://www.lebans.com Access Code, Tips and Tricks Please respond only to the newsgroups so everyone can benefit. Quote: > > Can someone tell me how can I conver a 24 bit image to > > a 256 color bitmap or to a JPG file? > To convert to an 8-bit bitmap requires more work than you may expect, mostly > because you've got to find the best palette to represent the image (24-bit > images aren't based on palette's where was <= 8-bit are). Various > colour-space quantisation methods exist and you can find information about > these if you do a search but be warned it's quite tricky. There is a VB > implementation on www.vbaccelerator.com though if you don't fancy giving it > a shot yourself. > To save as a .JPG then you'll need to grab the IJL off www.Intel.com and > you'll find a demonstration VB project in there that shows you how to > convert a bitmap to JPEG. > Hope this helps, > Mike > -- EDais -- > - Microsoft Visual Basic MVP - > WWW: Http://EDais.earlsoft.co.uk/
Sun, 18 Jul 2004 01:55:08 GMT

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