Re: Precise bitmaps

*To*: mathgroup at smc.vnet.net*Subject*: [mg96720] Re: Precise bitmaps*From*: ragfield <ragfield at gmail.com>*Date*: Sun, 22 Feb 2009 03:11:55 -0500 (EST)*References*: <gnq6ni$83g$1@smc.vnet.net>

On Feb 21, 6:37 pm, "Diamond, Mark" <d... at dot.dot> wrote: > A question was asked back in 2005 about precise bitmaps. I have a similar > question with regard to Mathematica version 7. > > Looking at the new image-manipulation functions in V7, I expected this to= be > quick ... I'd like to be able to create a series of stimuli for use in an > experiment. The first step in creating the stimuli is to create a 512 x 5= 12 > greyscale image with a white background and which contains the drawn > objects. > > I tried the following to create a JPEG image with dimensions 128x128 ... > > circ=Graphics[Circle[{0,0},62]] > rasterCirc=Rasterize[circ,RasterSize->{128,128}] > Export["circle.jpg",rasterCirc] > > but instead the image dimensions are 360 x 363 pixels. I had also hoped t= hat > I could obtain an antialiased arc but the only antialiasing option seems = to > be for Style, which then produces a non-Graphics object. > > Can anyone see a simple (i.e., not very low-level programming) solution t= o > the problem within Mathematica? What have I missed conceptually that woul= d > explain the 360x363 pixel dimensions instead of my expected 128x128? And = is > there a way to obtain the anti-aliased circle? circ = Graphics[Circle[{0, 0}, 62], ImageSize -> 128] rasterCirc = Rasterize[circ] (* this step is not strictly necessary *) Export["circle.jpg",rasterCirc] -Rob