Convert to f-strings where it makes sense

src/ocrmypdf/exec/__init__.py

@@ -39,25 +39,22 @@ def get_version(program, *, version_arg='--version', regex=r'(\d+(\.\d+)*)'):
         output = proc.stdout
     except FileNotFoundError as e:
         raise MissingDependencyError(
-            "Could not find program '{}' on the PATH".format(program)
+            f"Could not find program '{program}' on the PATH"
         ) from e
     except CalledProcessError as e:
         if e.returncode < 0:
             raise MissingDependencyError(
-                "Ran program '{}' but it exited with an error:\n{}".format(
-                    program, e.output
-                )
+                f"Ran program '{program}' but it exited with an error:\n{e.output}"
             ) from e
         raise MissingDependencyError(
-            "Could not find program '{}' on the PATH".format(program)
+            f"Could not find program '{program}' on the PATH"
         ) from e
     try:
         version = re.match(regex, output.strip()).group(1)
     except AttributeError as e:
         raise MissingDependencyError(
-            ("The program '{}' did not report its version. " "Message was:\n{}").format(
-                program, output
-            )
+            f"The program '{program}' did not report its version. "
+            f"Message was:\n{output}"
         )
 
     return version

src/ocrmypdf/exec/ghostscript.py

@@ -142,10 +142,10 @@ def rasterize_pdf(
                 '-dSAFER',
                 '-dBATCH',
                 '-dNOPAUSE',
-                '-sDEVICE=%s' % raster_device,
-                '-dFirstPage=%i' % pageno,
-                '-dLastPage=%i' % pageno,
-                '-r{0}x{1}'.format(str(int_res[0]), str(int_res[1])),
+                f'-sDEVICE={raster_device}',
+                f'-dFirstPage={pageno}',
+                f'-dLastPage={pageno}',
+                f'-r{str(int_res[0])}x{str(int_res[1])}',
             ]
             + (['-dFILTERVECTOR'] if filter_vector else [])
             + [
@@ -181,9 +181,7 @@ def rasterize_pdf(
             )
             if expected_size != im.size or page_dpi != (xres, yres):
                 log.debug(
-                    "Ghostscript: resize output image {} -> {}".format(
-                        im.size, expected_size
-                    )
+                    f"Ghostscript: resize output image {im.size} -> {expected_size}"
                 )
                 im = im.resize(expected_size)
 

src/ocrmypdf/exec/pngquant.py

@@ -43,7 +43,7 @@ def quantize(input_file, output_file, quality_min, quality_max):
         '--output',
         output_file,
         '--quality',
-        '{}-{}'.format(quality_min, quality_max),
+        f'{quality_min}-{quality_max}',
         '--',
         input_file,
     ]

src/ocrmypdf/exec/tesseract.py

@@ -159,7 +159,7 @@ def get_orientation(input_file, engine_mode, timeout: float, log):
 
 
 def tesseract_log_output(log, stdout, input_file):
-    prefix = "{0:4d}: [tesseract] ".format(page_number(input_file))
+    prefix = f"{(page_number(input_file)):4d}: [tesseract] "
 
     try:
         text = stdout.decode()
@@ -201,7 +201,7 @@ def tesseract_log_output(log, stdout, input_file):
 
 
 def page_timedout(log, input_file):
-    prefix = "{0:4d}: [tesseract] ".format(page_number(input_file))
+    prefix = f"{(page_number(input_file)):4d}: [tesseract] "
     log.warning(prefix + " took too long to OCR - skipping")