[Rd] image (PR#11493)

[Simon Urbanek]

On May 20, 2008, at 8:05 PM, jms2003 at med.cornell.edu wrote:

> Full_Name: Joseph Scandura
> Version: 2.7.0
> OS: Mac 10.5
> Submission from: (NULL) (140.251.50.94)
>
>
> Since updating to 2.7.0 all plots that use image() (heatmap, etc...)  
> now draw
> visible boxes around each rectangle in the plot. When there are many  
> rectangles
> the surrounding color becomes dominant over the rectangle color and  
> the overall
> image is borderline useless.
>

Can you, please, specify exactly which graphics device you are using  
and possibly a snapshot of the problem? I don't see any additional  
boxes being drawn on any device.

The only issue I'm aware of are anti-aliasing effects around the edges  
of adjacent rectangles which don't fall on the pixel boundary (if anti- 
aliasing device is used). Depending on the subpixel location of the  
edge, the background color may shine through very slightly. It's not  
what you describe, but it's closest to what I can imagine you could  
mean. However, AFAICS this has not been changed recently and is a  
rendering artifact which is hard to get rid of in the current setup as  
devices are resolution-independent (the only cure I'm aware of [short  
of disabling anti-aliasing]  is to distort the original plot such that  
rectangles are aligned with the pixels of the output medium).

Cheers,
Simon