[R] Basic: setting resolution and size of an R graphic

[Romain Francois]

Le 25.10.2005 14:59, Marc Schwartz a écrit :

>If you specifically need the plot to have a dimension measured in
>pixels, then you need to use a bitmapped format such as png and specify
>the output to be the size you require:
>
>  png("test.png", width = 300, height = 300, ...)
>  DoYourPlotHere()
>  dev.off()
>
>Do this directly using the png() device, rather than trying to convert
>the image format, which almost always introduces "noise".
>
>Since you are using a bitmapped format, you will experience the tradeoff
>with respect to the image quality (ie. pixelated) as compared to a
>vector based format such as PDF or PS.
>
>I would re-verify the requirements for the journal to which you are
>submitting the article relative to what they need for image specs. It
>seems unusual for a journal to request an image in this fashion, unless
>it is a photograph where a jpg format may be preferred or perhaps for
>online publication on a web page.
>
>HTH,
>
>Marc Schwartz
>  
>
Hi folks,

I just would like to highlight the argument 'pointsize' of the png 
function.
For graphics in RGG i use pointsize=4 and i'm happy with it.

Romain

>On Tue, 2005-10-25 at 08:57 +0200, Dr. med. Peter Robinson wrote:
>  
>
>>Thanks Marc and Jim for the tips. The PDF file that I create with R looks
>>about the same as the one you created. However, I need to get the graphic
>>to be a certain size (300 pixels wide). I have been using the ImageMagick
>>program to do so for other graphics:
>>
>>convert test.pdf -resize 300x300 out.pdf
>>
>>then out.pdf looks rather poor (pixelly). The original image is too big.
>>ANy ideas?
>>Thanks a lot,Peter
>>
>>
>>Am Mo, 24.10.2005, 22:53, schrieb Marc Schwartz (via MN):
>>    
>>
>>>On Mon, 2005-10-24 at 22:32 +0200, Dr. med. Peter Robinson wrote:
>>>
>>>      
>>>
>>>>Dear List,
>>>>
>>>>
>>>>I am sorry if this perhaps a too basic question, but I have not found
>>>>an answer in Google or in the R help system. I am trying to use R to do
>>>>a very simple analysis of some data (RT-PCR and Western analysis) with a
>>>> T-test and
>>>>to plot the results as a histogram with error bars. (I have pasted an
>>>>example script at the bottom of this mail). In order to use this for
>>>>publication, I would like to adjust the resolution and size of the final
>>>>image. However, even using file types such as postscript or pdf that are
>>>>vector based, I get rather bad-looking results with
>>>>        
>>>>
>>>>>pdf(file="test.pdf") source("script at bottom of mail") dev.off()
>>>>>          
>>>>>
>>>>using either pdf or postscript or jpg devices.
>>>>
>>>>
>>>>Therefore I would like to ask the list, how to best produce a graphic
>>>>from the script below that would fit into one column of a published
>>>>article and have a high resolution (as eps, or failing that tiff or
>>>>png)? Thanks in advance for any advice,
>>>>
>>>>
>>>>Peter
>>>>
>>>>        
>>>>
>>><Snip of code>
>>>
>>>
>>>What OS are you on?
>>>
>>>
>>>Running your example on FC4, I get the attached output for a pdf().
>>>
>>>
>>>I suspect that on your OS, the height and width arguments are not
>>>appropriate by default.
>>>
>>>Thus, you may need to adjust your pdf (or postscript) function call to
>>>explicitly specify larger height and width arguments.
>>>
>>>Also note that to generate an EPS file, pay attention to the details
>>>section of ?postscript, taking note of the 'onefile', 'horizontal' and
>>>'paper' arguments and settings.
>>>
>>>
>>>Also, check with your journal to see if they specify dimensions for such
>>>graphics so that you can abide by their specs if provided. If they are
>>>using LaTeX, there are means of specifying and/or adjusting the height
>>>and/or width specs in the code based upon proportions of various measures
>>>(ie. \includegraphics[width=0.9\textwidth]{GraphicsFile.eps} ).
>>>
>>>
>>>HTH,
>>>
>>>
>>>Marc Schwartz
>>>      
>>>


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| Romain FRANCOIS - http://francoisromain.free.fr               |
| Doctorant INRIA Futurs / EDF                                  |
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