Fix convert to gs

seminar/models.py

@@ -602,13 +602,18 @@ class Cislo(SeminarModelBase):
 			png_filename = pathlib.Path(tempfile.mkdtemp(), 'nahled.png')
 
 			subprocess.run([
-				"convert",
-				"-density", "300x300",
-				"-geometry", "{}x{}".format(VYSKA, sirka),
-				"-background", "white",
-				"-flatten",
-				"{}[0]".format(self.pdf.path),  # titulní strana
-				png_filename
+				"gs",
+				"-sstdout=%stderr",
+				"-dSAFER",
+				"-dNOPAUSE",
+				"-dBATCH",
+				"-dNOPROMPT",
+				"-sDEVICE=pngalpha",
+				"-r{}x{}".format(VYSKA, sirka),
+				"-dFirstPage=1d",
+				"-dLastPage=1d",
+				"-sOutputFile=" + str(png_filename),
+				"-f%s" % self.pdf.path
 				],
 				check=True,
 				capture_output=True