change image file to png

gnuplot/README.md

@@ -5,5 +5,5 @@
 
 [line.gp](./line.gp)
 
-![img](./line.svg)
+![img](./line.png)
 

gnuplot/README.org

@@ -1,4 +1,4 @@
 
 [[file:./line.gp][line.gp]]
 
-[[./line.svg]]
+file:./line.png

gnuplot/line.gp

@@ -2,14 +2,15 @@
 # usage:
 #   gnuplot -e "file='data.dat'; column1=1; column2=2; format=''; out=''" line.gp
 #
-# format = {'terminal', 'svg'}
+# format = {'terminal', 'png', 'svg'}
 
 if(!exists("file")) file = 'data.dat'
 if(!exists("column1")) column1 = 1
 if(!exists("column2")) column2 = 2
 if(!exists("format")) format = 'terminal'
 if(exist('format') && format eq 'terminal') set terminal dumb; set tics scale 0
-if(exist('format') && format eq 'svg') set terminal svg
+if(exist('format') && format eq 'png') set terminal png transparent
+if(exist('format') && format ne '') set terminal format
 if(exists("out")) set output out
 
 plot file u column1:column2 w l notitle