gnuplot> sinc(x) = sin(pi*x)/(pi*x) gnuplot> set xlabel "X" gnuplot> set ylabel "Y" gnuplot> unset key gnuplot> set samples 500 gnuplot> set xrange [-5:5] gnuplot> set xtics 1 gnuplot> set x2range [0:10] gnuplot> set x2tics 1 gnuplot> set y2range [-2:5] gnuplot> set y2tics 1 gnuplot> set grid gnuplot> set label 1 "Hello first" at 2,0.5 gnuplot> set label 2 "Hello second" at second 2,0.5 gnuplot> set label 3 "Hello graph" at graph 0.2,0.5 gnuplot> set label 4 "Hello screen" at screen 0.2,0.5 gnuplot> set label 5 "Hello character" at character 10,5 gnuplot> plot sinc(x)
这里我们画一个 sinc 函数图像。为了说明问题,我们把第二坐标系也都标示了出来,虽然函数图像并没有用到第二坐标。其他命令前面都讲过了,这里只看五个 set label 命令。set label 之后紧跟的那个整数,就是一个标识符,用以区别各个 label,可以随便选个整数。在字符串之后,at 参数指定标签坐标。默认为 first 坐标系统,也可以使用其它坐标系统。下面是生成的图片:
gnuplot> set label 1 "Hello red left" at 2,0.4 left textcolor rgb "#FF0000" gnuplot> set label 2 "Hello green center" at 2,0.5 center textcolor rgb "#00FF00" gnuplot> set label 3 "Hello blue right" at 2,0.6 right textcolor rgb "#0000FF" gnuplot> set label 4 "Hello rotate" at -2,0.4 rotate by 45 gnuplot> set label 5 "Hello point" at -3,0.2 point pt 7 lc rgb "#FF9900" gnuplot> replot