how can I save the pixels of a line, and draw the line with the pixels laterly.

[王旭光]

Hello everyone!
     I want to do the following 3 steps:
         1  save the pixels of the line (x1,y1)-- (x2, y2) in the cairo_t
         2  draw the line using a special color
         3  sometime later, draw the line using the pixels saved in step1. (the same as erasing the line).
    But I don't know how to finish the step1 and step3.
    Help me, thanks a lot.

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09年新晋3D主流网游《天下贰》，网易六年亿资打造
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[M Joonas Pihlaja]

Hi,

Cairo doesn't have any special magic for copying pixels under a line,
so you'll need to copy the pixels under the line yourself.  The
simplest way of course is to make a copy of the destination surface
before drawing, or you can get fancy and only copy the parts of the
destination under the line.

Cheers,

Joonas
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