# set terminal pngcairo  background "#ffffff" enhanced font "arial,8" fontscale 1.0 size 540, 360 
# set output 'rgbalpha.2.png'
set border 31 front linecolor rgb "gold"  linewidth 1.000 dashtype solid
set key title "Plot style rgbalpha" center
set key at screen 0.75, 0.75 left bottom vertical Left noreverse enhanced autotitle nobox
set key noinvert samplen 1 spacing 1 width -7 height 0
set object  1 rect from screen 0, 0 to screen 1, 1
set object  1 behind clip lw 1.0  dashtype solid fc  rgb "grey10"  fillstyle   solid 1.00 noborder
set samples 128, 128
set size ratio 0.95 1,1
set style data lines
set xrange [ 0.00000 : 128.000 ] noreverse nowriteback
set x2range [ * : * ] noreverse writeback
set yrange [ 0.00000 : 128.000 ] noreverse nowriteback
set y2range [ * : * ] noreverse writeback
set zrange [ * : * ] noreverse writeback
set cbrange [ * : * ] noreverse writeback
set rrange [ * : * ] noreverse writeback
set lmargin at screen 0.1
set bmargin at screen 0.1
set tmargin at screen 0.9
focus(x,y) = ((column(0)-x)**2 + (column(-1)-(127-y))**2) > 400 ? 0 : 255
NO_ANIMATION = 1
## Last datafile plotted: "lena.rgb"
plot 100.*(.4+sin(x/5.)/(x/5.)) lw 5 title 'solid line',      'lena.rgb' binary array=(128,128) format="%uchar" flipy using 1:2:3:(focus(70,50))                 with rgbalpha title "Lena with circular mask"