Dear list, I have two questions regarding grid.symbols() in the grImport package. This package allows you to import a vector graphic in R, and grid.symbols() can be used to plot the resulting glyph at arbitrary locations in a grid viewport. I have tried the code in the grImport vignette, which is most interesting, however I am stuck with two problems: 1- Is there a possibility to create a Picture object directly from R without importing an external image, but rather specified as a regular grob/gTree, say. I would like to imitate my.symbols from TeachingDemos, but with grid. 2- I could not figure out what the size argument in grid.symbols() does. The following example fails rather curiously. petal.ps <- "%!PS newpath % start a new shape 0 0 moveto % move to a start location -5 10 lineto % line to a new location -10 20 10 20 5 10 curveto % curve to a third location 5 10 lineto % line to a fourth location closepath % connect back to the start location 0 setgray % set the drawing colour to black fill % fill the current shape" cat(petal.ps, file="petal.ps") library(grImport) PostScriptTrace("petal.ps") petal <- readPicture("petal.ps.xml") grid.symbols(petal, 1:10/10, 1:10/10, size=0.1) # OK grid.symbols(petal, 1:10/10, 1:10/10, size = seq(0.01, 0.1, length=10)) # Warning and weird shapes sessionInfo() R version 2.13.1 (2011-07-08) Platform: i386-apple-darwin9.8.0/i386 (32-bit) locale: [1] en_GB.UTF-8/en_GB.UTF-8/C/C/en_GB.UTF-8/en_GB.UTF-8 attached base packages: [1] stats graphics grDevices utils datasets grid methods base other attached packages: [1] grImport_0.7-3 XML_3.4-0 ggplot2_0.8.9 proto_0.3-9.2 reshape_0.8.4 [6] plyr_1.5.2 loaded via a namespace (and not attached): [1] tools_2.13.1 Best regards, baptiste
Hi baptiste auguie wrote:> Dear list, > > I have two questions regarding grid.symbols() in the grImport package. > This package allows you to import a vector graphic in R, and > grid.symbols() can be used to plot the resulting glyph at arbitrary > locations in a grid viewport. > > I have tried the code in the grImport vignette, which is most > interesting, however I am stuck with two problems: > > 1- Is there a possibility to create a Picture object directly from R > without importing an external image, but rather specified as a regular > grob/gTree, say. I would like to imitate my.symbols from > TeachingDemos, but with grid.You can directly create a Picture object. An example is on slide 18 of stat.auckland.ac.nz/~paul/Talks/import.pdf> 2- I could not figure out what the size argument in grid.symbols() > does. The following example fails rather curiously. > > petal.ps <- "%!PS > newpath % start a new shape > 0 0 moveto % move to a start location > -5 10 lineto % line to a new location > -10 20 10 20 5 10 curveto % curve to a third location > 5 10 lineto % line to a fourth location > closepath % connect back to the start location > 0 setgray % set the drawing colour to black > fill % fill the current shape" > > cat(petal.ps, file="petal.ps") > library(grImport) > PostScriptTrace("petal.ps") > petal <- readPicture("petal.ps.xml") > > grid.symbols(petal, 1:10/10, 1:10/10, size=0.1) # OK > > grid.symbols(petal, 1:10/10, 1:10/10, size = seq(0.01, 0.1, > length=10)) # Warning and weird shapesThat's a bug in 'grImport' (could not cope with 'size' of length > 1). A fix is winging its way to CRAN now. Paul> sessionInfo() > R version 2.13.1 (2011-07-08) > Platform: i386-apple-darwin9.8.0/i386 (32-bit) > > locale: > [1] en_GB.UTF-8/en_GB.UTF-8/C/C/en_GB.UTF-8/en_GB.UTF-8 > > attached base packages: > [1] stats graphics grDevices utils datasets grid > methods base > > other attached packages: > [1] grImport_0.7-3 XML_3.4-0 ggplot2_0.8.9 proto_0.3-9.2 reshape_0.8.4 > [6] plyr_1.5.2 > > loaded via a namespace (and not attached): > [1] tools_2.13.1 > > Best regards, > > baptiste > > ______________________________________________ > R-help at r-project.org mailing list > stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.-- Dr Paul Murrell Department of Statistics The University of Auckland Private Bag 92019 Auckland New Zealand 64 9 3737599 x85392 paul at stat.auckland.ac.nz stat.auckland.ac.nz/~paul