count colors in bitmap
in [Visual Basic]
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From: charles on 7 Jul 2010 06:03 Hi Is there a way that I can quickly count the number of unique colors in a bitmap using VB6? I have found some examples on the web which seem to work fine but they are all quite slow, taking about two seconds to count the number of unique colors in a 1600 x 1200 pixel bmp. Can it be done any faster than this? Charles
From: Mike Williams on 7 Jul 2010 07:03 "charles" <cbabbage59(a)yahoo.com> wrote in message news:273aa1c5-fb8a-47c5-b1ee-8fd191777a1b(a)u7g2000yqm.googlegroups.com... > Hi. Is there a way that I can quickly count the > number of unique colors in a bitmap using VB6? Yes. > I have found some examples on the web which seem > to work fine but they are all quite slow, taking about > two seconds to count the number of unique colors in > a 1600 x 1200 pixel bmp. Can it be done any faster > than this? Yes. Mike NOTICE: This response has been deliberately kept short in order to comply with the Posting Restrictions [Maximum Content] Order (2010) recently issued by Larry Serflaten, the newly self appointed group moderator. We apologise for any inconvenience which may be caused whilst Larry is attempting to establish his new regime and to fill the vacuum left by the departure of the Micro$oft puppeteers. Normal service will be resumed as soon as possible. In the meantime if you should require a more detailed answer to this or to any other question then you may contact the newly self appointed moderator directly at serflaten(a)gmail.com
From: Dee Earley on 7 Jul 2010 08:30 On 07/07/2010 11:03, charles wrote: > Hi > > Is there a way that I can quickly count the number of unique colors in > a bitmap using VB6? I have found some examples on the web which seem > to work fine but they are all quite slow, taking about two seconds to > count the number of unique colors in a 1600 x 1200 pixel bmp. Can it > be done any faster than this? Whetever method you use will need to go through all the pixels and look. It will be faster if you run through the DIB data rather than many GetPixel calls, but it will depend on your code. -- Dee Earley (dee.earley(a)icode.co.uk) i-Catcher Development Team iCode Systems (Replies direct to my email address will be ignored. Please reply to the group.)
From: Larry Serflaten on 7 Jul 2010 09:35 "charles" <cbabbage59(a)yahoo.com> wrote > Is there a way that I can quickly count the number of unique colors in > a bitmap using VB6? I have found some examples on the web which seem > to work fine but they are all quite slow, taking about two seconds to > count the number of unique colors in a 1600 x 1200 pixel bmp. Can it > be done any faster than this? Did your examples access the image data from an array? Did you see this? http://www.vbaccelerator.com/codelib/gfx/dibsect.htm LFS
From: charles on 7 Jul 2010 10:03
On 7 July, 14:35, "Larry Serflaten" <serfla...(a)gmail.com> wrote: > Did your examples access the image data from an array? > Did you see this?http://www.vbaccelerator.com/codelib/gfx/dibsect.htm Yes, and I also saw the following vbaccelerator code which uses a cDibSection Class to count the colors. http://www.vbaccelerator.com/home/vb/code/vbmedia/image_processing/Counting_Colours/Count_Colours_Sample.asp The problem is that it is quite slow, taking about two seconds for my sample 1600 x 1200 pixel .bmp file. It runs a bit faster on my other machine, about one and a half seconds, but it returns a completely different answer for exactly the same .bmp file! Is there a faster and more reliable way? Charles |