<html>
  <head>

    <meta http-equiv="content-type" content="text/html; charset=GB2312">
  </head>
  <body bgcolor="#FFFFFF" text="#000000">
    Hi cairo developers,<br>
    <br>
    I wanna draw some points indicating mouse`s X and Y, and used random
    number from 0 to 255 for RGB color of the points, such as:<br>
    <br>
    for loop <br>
    {                                                                      
                                   <br>
            double r = Map(i, 0, 100, 0, 255);    // Re-maps a number
    from one range to another
    <a class="moz-txt-link-freetext" href="http://www.openframeworks.cc/documentation/math/ofMath.html#show_ofMap">http://www.openframeworks.cc/documentation/math/ofMath.html#show_ofMap</a><br>
            double g =
    0;                                                       <br>
            double b = 255 -
    r;                                                
                                                                 <br>
            cairo_set_source_rgb(c, r / 255.0, g / 255.0, b /
    255.0);           <br>
            cairo_move_to(c, x,
    y);                                             <br>
           
    cairo_close_path(c);                                               
    <br>
    }                                                                      
    <br>
    cairo_stroke(c);<br>
    <br>
    It is unable to put cairo_stroke into the for loop, it might be a
    heavy operation when draw the path too often.<br>
    But cairo_set_source_rgb failed to take effect in the loop if
    cairo_stroke was outside.<br>
    <br>
    The source code is available via
    <meta http-equiv="content-type" content="text/html; charset=GB2312">
    <a
href="https://github.com/xiangzhai/grt/tree/master/GRTExamples/ClassificationModulesExamples/CairoX11DTWExample">https://github.com/xiangzhai/grt/tree/master/GRTExamples/ClassificationModulesExamples/CairoX11DTWExample</a><br>
    <br>
    So how to take cairo_set_source_rgb effect for drawing different
    color points?<br>
    Please someone give me some advice, Thanks a lot :)<br>
    <br>
    Best,<br>
    <br>
    Leslie Zhai<br>
  </body>
</html>