gnuplot - gnuplot 返回正确的图形，但也返回多个 CGContext 错误

Question

这是我用来使用 gnuplot 生成图形的代码：

set terminal pngcairo size 500,650 enhanced font 'Verdana,10'
set yrange [0:100]
set xrange [10:100]
set title "angles set 1" font "Arial,12"
set output 'angles.png'
set style line 1 lc rgb '#0060ad' lt 1 lw 2 pt 7 ps 1.5
plot 'angfreqs.csv' with impulses lw 2

它准确地绘制了我想要的图形，但也返回以下错误：

gnuplot[92995] <Error>: CGContextSetFont: invalid context 0x0
gnuplot[92995] <Error>: CGContextSetFontSize: invalid context 0x0
gnuplot[92995] <Error>: CGContextSetTextMatrix: invalid context 0x0
gnuplot[92995] <Error>: CGContextSaveGState: invalid context 0x0
gnuplot[92995] <Error>: CGContextSetCompositeOperation: invalid context 0x0
gnuplot[92995] <Error>: CGContextFillRects: invalid context 0x0
gnuplot[92995] <Error>: CGContextRestoreGState: invalid context 0x0
gnuplot[92995] <Error>: CGContextSetRGBFillColor: invalid context 0x0
gnuplot[92995] <Error>: CGContextShowGlyphsAtPoint: invalid context 0x0
gnuplot[92995] <Error>: CGContextSetFont: invalid context 0x0
gnuplot[92995] <Error>: CGContextSetFontSize: invalid context 0x0
gnuplot[92995] <Error>: CGContextSetTextMatrix: invalid context 0x0
gnuplot[92995] <Error>: CGContextSaveGState: invalid context 0x0
gnuplot[92995] <Error>: CGContextSetCompositeOperation: invalid context 0x0
gnuplot[92995] <Error>: CGContextFillRects: invalid context 0x0
gnuplot[92995] <Error>: CGContextRestoreGState: invalid context 0x0
gnuplot[92995] <Error>: CGContextSetRGBFillColor: invalid context 0x0
gnuplot[92995] <Error>: CGContextShowGlyphsAtPoint: invalid context 0x0

我需要设置更多参数还是我定义不正确？