count colors in bitmap
in [Visual Basic]
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From: Mike Williams on 12 Jul 2010 04:10 "Larry Serflaten" <serflaten(a)gmail.com> wrote in message news:i1ds1d$a12$1(a)news.eternal-september.org... > nar�cis�sism - noun > 1.inordinate fascination with oneself; excessive self-love; vanity. Yes, I know what narcissism means, Larry. There is no need for you to post an extract from the dictionary in order to imply that you know what it means but others do not. Your superiority complex is showing ;-) Mike
From: Kevin Provance on 12 Jul 2010 10:54 "Larry Serflaten" <serflaten(a)gmail.com> wrote in message news:i1ds1d$a12$1(a)news.eternal-september.org... : : nar7cis7sism - noun : 1.inordinate fascination with oneself; excessive self-love; vanity. : 2.Psychoanalysis. erotic gratification derived from admiration of one's : own physical or mental attributes, being a normal condition at the : infantile level of personality development. O_o Dayum, that's my ex-wife to a bloody T. Now I have something else to taunt her with. Thanks! <g> -- Customer Hatred Knows No Bounds at MSFT Free usenet access at http://www.eternal-september.org ClassicVB Users Regroup! comp.lang.basic.visual.misc Bawwk! Paulie want a dingleball, bawwk!
From: Mike Williams on 12 Jul 2010 16:33 "Larry Serflaten" <serflaten(a)gmail.com> wrote in message news:i1ds1d$a12$1(a)news.eternal-september.org... > Are you not quite all grown up yet Mike? Yes, I'm all grown up Larry. When do you plan on growing up? Mike
From: Ulrich Korndoerfer on 13 Jul 2010 22:55 Hi, Mike Williams schrieb: > ... > Full colour 24 bit Bitmaps that occupy an /exact/ multiple of 4KB of DIB > data are in fact quite common (1024 x 768, 2048 x 1536, 3072 x 2304 and 3200 > x 2400 and some others are all fairly common bitmap sizes that fall into > this category) and Ulrich's code, as it stands, will crash on all of those > bitmaps. > ... I did some rework of my code. It does not crash on those sizes. I have setup a test project, available under <http://www.prosource.de/Temp/CountUniqueColors.zip> This tester allows to time and test your version and three of my versions (in module MFinal). Just double click anywhere in the window to start a test. For a new picture file just drag and drop a file from Explorer anywhere on the window. My three versions use different access methods. gUniqueColorCountFromDIB has complicated code and is as fast as your version, gUniqueColorCountFromDIB1 has less complicated code and is a bit slower, gUniqueColorCountFromDIBByte has easy code and is nearly as fast as gUniqueColorCountFromDIB. gUniqueColorCountFromDIB andgUniqueColorCountFromDIB1 both can treat the last pixel problem. There is a compilation constant (LASTPIXELSPECIALTREATMENT) in MFinal, which switches special treatment of the last pixel on or off. When off, for the sizes you mentioned above, the code does access a byte that lies outside the memory occupied by the DIB data, but does not crash. BTW, your code counts wrong on bitmaps having a width of either 1, 2 or 3 pixels. And, when run in the IDE, would most probably crash on a system with more than 2 GB process memory. -- Ulrich Korndoerfer VB tips, helpers, solutions -> http://www.prosource.de/Downloads/ MS Newsgruppen Alternativen -> http://www.prosource.de/ms-ng-umzug.html
From: Ulrich Korndoerfer on 13 Jul 2010 23:07
Hi, sorry for replying so late. charles schrieb: > ... > Thanks Ulrich. That's almost as fast as Mike's code so it should be > quite useful. There is one little problem with your code though in > that it crashes on some bitmaps and I get the "Send Error Report to > Microsoft" message box. Any idea what might be causing that? > ... No. I reworked my code a little bit. You can download a test project from <http://www.prosource.de/Temp/CountUniqueColors.zip> See also my reply to Mike. My code versions now can be switched to treat the access to the last pixel problem or not, which was suspected by Mike that this could cause a crash due to a memory access violation. However I can not replicate it. You could test it on your own machine, with your own pixels. Just set in module MFinal the compilation constant (LASTPIXELSPECIALTREATMENT) to 1 (then the last pixel is accessed in a special way to not exceed the memory needed for the bitmap pixel data) or to 0 (then no special measures are taken). Then run it in the IDE and also compile it and run compiled too. I would be interseted if you then still see crashes. BTW, there are 3 versions of mine to demonstrate, that complex code may often give some speed gains, but also often not so much that it is worth to fiddle around. The straight forward and simple version gUniqueColorCountFromDIBByte is nearly as fast as the most complicated one. -- Ulrich Korndoerfer VB tips, helpers, solutions -> http://www.prosource.de/Downloads/ MS Newsgruppen Alternativen -> http://www.prosource.de/ms-ng-umzug.html |