Joachim, Sorry I misunderstood your problem. It is probably not easy to do so unless you are willing to hack into hexbin::grid.hexagons and flowViz::panel.xyplot.flowframe. If it is just for small data set, you can simply use bin the data and do ggplot on the data.frame ,which gives you more flexibility in coloring. Here is one example: library(ggplot2) mat<-exprs(fs[[1]]) x<- mat[,"FSC-H"] y<- mat[,"SSC-H"] bin <- hexbin(x,y, xbin = 128) df <- data.frame(hcell2xy(bin), count = bin at count) ggplot(df, aes(x = x, y = y)) + geom_point(aes(color = sqrt(count))) + scale_color_gradient(low = "white", high = "black" , na.value = "red", limit = c(1, 2)) + theme_bw() Yon change use the 'limit' and 'na.value' to thresholding the colors. Mike Mike On 08/12/2014 05:42 AM, Joachim Schumann wrote: > Hi Mike, > > I did not get the point how to write a color ramp function with a > treshold. > > Right now I'm creating the xyplots like that: > > ff<-read.FCS("test.fcs",alter.names=TRUE,transformation=FALSE,min.li mit=NULL) > colramp <- colorRampPalette(c("white","black"))(236) > col=colorRampPalette(colramp) > xyplot(FS.Log ~ FL.4.Log ,data=ff, smooth=FALSE, xbin=128, colramp=col > ,par.settings = list(panel.background=list(col = "white")), axis = > axis.default, scales=(list(x=list(draw=FALSE), y=list(draw=FALSE))), > xlab="", ylab="") > > I can get the maximal value by: > > mat<-exprs(ff) > x<-mat[,"FS.Log"] > y<-mat[,"FL.4.Log"] > bin<-hexbin(x,y,xbins=128) > c<-bin at count > m<-max(c) > > The counts should be the values plotted by the xyplot function, right? > > How can I define the color palette with 236 linear gradiations from > white to black starting by 0, ending by e.g. m-100. All the other > values (m-100 to m) shall be black. > > Thank. > > Joachim > > Am 24.03.2014 18:34, schrieb Mike: >> >> If you use |hexbin| version of |xyplot|, then the value is simply the >> cell counts falling into each hexagon. >> It is not difficult to write your own customized colour ramp function >> to generate color schemes that you described based on your threshold. >> >> There are a little hacking you need to do in order to get the count >> value of each hexagon though, firstly you need to call |hexbin| on >> each |flowFrame|, >> >> |bin <- hexbin(x,y,xbins=xbins) >> | >> >> |x, y| is the intensity values from the two channels you defined in >> formula (e.g. |SSC-H|~|FSC-H|), which you can get by >> >> |mat <- exprs(fs[[1]]) >> x <- mat[, channel_A) >> y <- mat[, channel_B) >> | >> >> then you get the the counts vector by |bin at count|. >> >> Mike >> >> On 03/22/2014 03:44 AM, Joachim Schumann wrote: >> >>> Hi Mike, >>> >>> thanks for your answer. I defined a colramp from white to black now. >>> Is there any way I can have a look at the values that are calculated >>> within the xyplot? The reason: I want to define a threshold. E.g.: >>> The highest value within the xyplot is 1000, the lowest is 0. I want >>> all values ranging from 900-1000 beeing black and all values from >>> 900-0 should have those 255 gradiations. >>> >>> Best, >>> Joachim >>> >>> Am 20.03.2014 19:04, schrieb Mike: >>>> 'colramp' argument is what you are looking for, here is the example >>>> code. >>>> >>>> library(flowViz) >>>> data(GvHD) >>>> fs <- GvHD[1:2] >>>> >>>> #generate all colors you need >>>> myColors <- gray.colors(255) >>>> #reverse it as you want dark for high and white for low >>>> myColors <- rev(myColors) >>>> #wrap it into a ramp function >>>> myColRamp <- colorRampPalette(myColors) >>>> >>>> # pass the ramp function to xyplot >>>> xyplot(`SSC-H`~`FSC-H`, fs, smooth = FALSE, xbin = 128, colramp = >>>> myColRamp) >>>> >>>> >>>> Mike Jiang >>>> >>>> On 03/18/2014 09:34 AM, Joachim Schumann wrote: >>>>> Hi Mike, >>>>>> >>>>>> thanks for your answer. I think xbin is the only thing I need. But I >>>>>> have another question: I want to create a xyplot of my data. The >>>>>> range >>>>>> of e.g. columns FS.Log and FL.4.Log is from 0-4095. I want to display >>>>>> the xyplot (FL.4.Log ~ FS.Log) as a grayscale image with 256 linear >>>>>> gradiations. Black should indicate 4095 (maxRange) and white should >>>>>> indicate 0 (minRange). Now I need 256 linear gradiations from >>>>>> black to >>>>>> white. The data resolution should be 128. >>>>>> Can you tell me how to create such a grayscale image? I attached an >>>>>> image showing the grayscale. >>>>>> >>>>>> Best, >>>>>> Joachim >>>>>> >>>>>> >>>>>> Am 14.03.2014 18:07, schrieb Mike: >>>>>> > `nbin` is for displaying the marginal events (i.e. those gray >>>>>> segments >>>>>> > piled up at the edges) >>>>>> > >>>>>> > `binSize` is for `timeline plotting`, i.e. when you do 'xyplot' >>>>>> on a >>>>>> > `flowFrame` without 'formula` supplied , for example: >>>>>> > >>>>>> > xyplot(GvHD[["s5a05"]], binSize = 100) >>>>>> > >>>>>> > So again, 'xbin' is the argument to adjust the 'resolution' for >>>>>> > 'non-smoothed' xyplot . e.g. >>>>>> > >>>>>> > xyplot(`FSC-H` ~ `SSC-H`, GvHD[["s5a05"]], smooth = FALSE, xbin >>>>>> = 32) >>>>>> > #lower resolution and faster rendering >>>>>> > >>>>>> > xyplot(`FSC-H` ~ `SSC-H`, GvHD[["s5a05"]], smooth = FALSE, xbin >>>>>> = 128) >>>>>> > #higher resolution and slower rendering >>>>>> > >>>>>> > >>>>>> > Mike >>>>>> > >>>>>> > >>>>>> > On 03/13/2014 04:08 AM, Joachim Schumann wrote: >>>>>> >> Yes, i meant the xyplot. Can I also change the number of events >>>>>> >> within one bin? The vignette sometimes says nbin, sometimes >>>>>> binSize. >>>>>> >> >>>>>> >> Am 12.03.2014 18:11, schrieb Mike: >>>>>> >>> Not sure what you mean by `histogram`. If you are talking about >>>>>> >>> `xyplot`, there is `xbin` argument to adjust resolution (when you >>>>>> >>> set `smooth = FALSE`). >>>>>> >>> >>>>>> >>> Mike >>>>>> >>> On 03/12/2014 05:32 AM, Joachim Schumann wrote: >>>>>> >>>> Hi Mr. Jiang, >>>>>> >>>> >>>>>> >>>> I'm using flowViz to create a histogram of my flow >>>>>> cytometric data. >>>>>> >>>> Is there any way I can adjust the data resolution (eg to 128) >>>>>> >>>> within the histogram? >>>>>> >>>> >>>>>> >>>> Best regards, >>>>>> >>>> Joachim >>>>>> >>>> >>>>>> >>> >>>>>> >> >>>>>> >> >>>>>> > >>>>>> >>>>>> >>>>>> -- >>>>>> M. Sc. Joachim Schumann >>>>>> Department of Environmental Microbiology >>>>>> AG Flow Cytometry >>>>>> Helmholtz Centre for Environmental Research - UFZ >>>>>> Permoserstra?e 15, 04318 Leipzig >>>>>> >>>>>> E-Mail: joachim.schumann at ufz.de >>>>>> http://www.ufz.de >>>>>> >>>>> -- >>>>> Joachim Schumann >>>>> Department of Environmental Microbiology >>>>> AG Flow Cytometry >>>>> Helmholtz Centre for Environmental Research - UFZ >>>>> Permoserstra?e 15, 04318 Leipzig >>>>> E-Mail: joachim.schumann at ufz.de <mailto:joachim.schumann at="" ufz.de=""> >>>>> http://www.ufz.de >>>> >>> >>> >>> -- >>> M. Sc. Joachim Schumann >>> Department of Environmental Microbiology >>> AG Flow Cytometry >>> Helmholtz Centre for Environmental Research - UFZ >>> Permoserstra?e 15, 04318 Leipzig >>> >>> E-Mail:joachim.schumann at ufz.de >>> http://www.ufz.de > > > -- > M. Sc. Joachim Schumann > Department of Environmental Microbiology > AG Flow Cytometry > Helmholtz Centre for Environmental Research - UFZ > Permoserstra?e 15, 04318 Leipzig > > E-Mail:joachim.schumann at ufz.de > http://www.ufz.de [[alternative HTML version deleted]]