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incorrect linetype with pdf device (PR#14128)

2 messages · Baptiste Auguie

Original
Baptiste Auguie
# 
Dear list,

A small follow up on this issue. The same behavior is observed for
postscript() and pdf(), so I suspect the erroneous code is in
grDevices/src/devPS.c. In particular, this macro,

static void
PostScriptSetLineTexture(FILE *fp, const char *dashlist, int nlty, double lwd)
{
/* use same macro for Postscript and PDF */
#define PP_SetLineTexture(_CMD_)						\
    double dash;								\
    int i;									\
    fprintf(fp,"[");								\
    for (i = 0; i < nlty; i++) {						\
	dash = (lwd >= 1 ? lwd: 1) *						\
	    ((i % 2) ? dashlist[i] + 1						\
	     :((nlty == 1 && dashlist[i] == 1.) ? 1. : dashlist[i] - 1));	\
	if (dash < 0) dash = 0;							\
	fprintf(fp," %.2f", dash);						\
    }										\
    fprintf(fp,"] 0 %s\n", _CMD_)

    PP_SetLineTexture("setdash");
}


I think the dash pattern should be

dash = (lwd >= 1 ? lwd: 1) *						\
	    ((i % 2) ? dashlist[i] 						\
	     :((nlty == 1 && dashlist[i] == 1.) ? 1. : dashlist[i] ));

instead (but I don't know C well enough to be sure).


Best regards,

baptiste
1 day later
Baptiste Auguie
# 
Dear all,

Running this minimal example,

library(grid)
postscript("test-123456.eps")
grid.newpage()
grid.lines(gp=gpar(lty="123456", lineend = "butt"))
dev.off()

produces eps output with the following setdash description towards the
end of the file,

## [ 0.00 3.00 2.00 5.00 4.00 7.00] 0 setdash

I consulted the postscript reference manual (page 667 *), which
indicates that the array should rather be [1 2 3 4 5 6] as intended
(and as produced by, e.g., quartz())

(*): http://www.adobe.com/products/postscript/pdfs/PLRM.pdf

Regards,

baptiste