Programatically How do I reset colors in PDF

I am creating a PDF file and I would like to generate several rectangles on the page However once I fill a rectangle in color I cannot reset the fill color (non-stroking color) to clear, white, transparent or whatever is needed so that no color is in the rectangle

I use t开发者_运维百科his to set the stroke and non-stroke to red

1.0  0.0  0.0 rg
1.0  0.0  0.0 RG

I set the line width

1 w

I draw a rectangle and it appears as a red rectangle (outlined and filled in red)

0046.8 0633.6 0237.6 0100.8 re
B

Now I set the stroke to black

0.0  0.0  0.0 RG

I attempt to create another rectangle (I only want black outline)

0072.0 0576.0 0288.0 0144.0 re
B

But the second rectangle appears with a black outline but is filled in red? How do I get red of the red fill?

Your problem is your use of B. If you interchange the two drawing operations you'll see that (what was) the second rectangle is now filled with black, because black is the default color. You should use S for the second rectangle, so that that path is stroked but not filled.

By the way, you're missing some really easy ways to reduce the size of your generated PDF:

• Use g/G instead of rg/RG when all three numbers are the same.
• 1 w is unnecessary (unless returning to that setting from a different one), 1 is the default value for stroke width.
• Don't print trailing .0 or leading zeroes on your numbers.

Putting all which together, here's what your generated page stream should look like:

1 0 0 rg 1 0 0 RG
46.8 633.6 237.6 100.8 re B
0 G
72 576 288 144 re S