Re: Miscellaneous questions
- To: mathgroup at smc.vnet.net
- Subject: [mg36822] Re: Miscellaneous questions
- From: "Steve Gray" <stevebg at adelphia.net>
- Date: Fri, 27 Sep 2002 04:15:26 -0400 (EDT)
- References: <amrjfe$5av$1@smc.vnet.net> <amuif5$cc3$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
"Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de> wrote in message news:amuif5$cc3$1 at smc.vnet.net... > Hi, [snip] > > 2. I'm using Raster to plot data points > > in a 256x256 array. Two problems: First, > > regardless of the ImageSize setting (I need the > > display as big as possible), the individual data cells > > when examined closely at 300% vary in size by > > almost 2:1. This makes detailed inspection of the > > data values difficult. Surely there is some setting > > of something which would make each data cell an > > exact number of screen pixels? GRAY: (No answer received.) I can get around this by making the images bigger but this is not a complete solution. > > Second, I'm using > > Show[ Graphics[Raster[ rescol, > > ColorFunction -> Hue]], > > AspectRatio -> Automatic, > > ImageSize -> 700]; > > but the Hues don't allow enough easily distinguishable > > shades to visually recognize even 6 data values easily. > > (I'm slightly colorblind.) > > The most humans can distinguish 160 gray levels > > >It would be nice to have black > > and white available for two of the data values, but Hue > > does not allow this. > > And something like: > > mycolor[i_] := > Switch[Round[i], > 0, RGBColor[0, 0, 0], > 1, RGBColor[1, 0, 0], > 2, RGBColor[1, 1, 0], > 3, RGBColor[0, 1, 0], > 4, RGBColor[0, 1, 1], > 5, RGBColor[0, 0, 1], > _, RGBColor[1, 1, 1]] > > Show[Graphics[ > Raster[Table[Random[Integer, {0, 6}], {16}, {16}], > ColorFunction -> mycolor, ColorFunctionScaling -> False]]] GRAY: Sounds good. I'll try it. Interesting that the help does not contain this in a form I could easily find. > > 3. I wanted to get this raster image into a format > > where I could dissect it with Photoshop or equivalent. > > And ? what does Export[] do ? it write the expression > in a desired format, TIFF, PNG, PPM are all lossless > compressed bitmap formats, that Mathematica can export > and that can be imported into PhotoShop GRAY: I foolishly thought something like Export would be under the File menu. > > After much fooling around, I found that I can export the > > selection as an html file, read it into Navigator, do File> > > Edit Page, which brings up Netscape Composer, right > > click the image which, allows saving it as a GIF, which > > I can finally work on with a photo editor. Maybe > > there is an easier way, or maybe this description will > > help someone with the same need. GRAY: I just found that simply Copying the image and Pasting it into Paint Shop Pro (or no doubt lots of other bitmap editors) works. For outputting a Raster noninteractively, there is Export, but I haven't tried it yet. Jens, thank you for your reply.