Malcolm Malcolm Greene wrote: > Paul, > > Your approach seems reasonable. If performance becomes an issue, I > think(?) you may find it faster to parse the BMP image as a text file > vs. use the GDI (or GDIPluse) API's to retrieve individual pixel color > values. > > Curious why you're interested in the number of unique colors in a > picture? It all started with a thematic mapping app and color schemes for legends - and I got a bit sidetracked ! I had started off with some color schemes which I had grabbed off-screen, one color at a time, and saved in a table. I then used GDIPlus to create some color swatches (small rectangular bitmaps containing a row of squares each in a different color belonging to the scheme). I then used these swatches in a drop-down list to enable selection of the schemes. Very sweet - worked beautifully, but ...
Then I got side-tracked. I thought why don't I grab a screen (or part of a screen - maybe a map legend, or maybe the map itself) and then use VFP to get the colors from that "capture" into my table of color schemes. All of this is really for my own amusement - a way of keeping mentally active, if you like. I don't think it's going to go anywhere, because .... A strange thing came to light yesterday regarding the number of colors in the images. One of my schemes has 13 colors and I had created a swatch for it with 13 colored squares, black borders and a white background. I then saved this swatch in various formats - BMP, GIF, JPG, PNG, TIF (all of this done with GDI). I expected these images to contain 15 colors (13+B+W) but to my surprise when I opened them in PaintShop the GIF had 34 colors, the BMP, PNG and TIF had 40 colors, and the JPG reports 2342 colors ! BTW these are the same numbers I am getting from the code I posted, which is comforting but VERY strange - I think I may go back to grabbing the colors one at a time by hand ! Paul Newton _______________________________________________ Post Messages to: [email protected] Subscription Maintenance: http://leafe.com/mailman/listinfo/profox OT-free version of this list: http://leafe.com/mailman/listinfo/profoxtech Searchable Archive: http://leafe.com/archives/search/profox This message: http://leafe.com/archives/byMID/profox/[EMAIL PROTECTED] ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
