Figure.savefig() reports confusing errors when saving image into a non-existent directory #2092
Description
Description of the problem
Figure.savefig() reports errors when saving an image to a subdirectory that doesn't exist. The error messages are very confusing.
I think we should check if the parent directory of the image exists before saving an image. If the directory doesn't exist, we have two options:
- Report that parent directories are missing and users should create these directories manually
- Create any missing parent directories automatically before saving
Full code that generated the error
import pygmt
fig = pygmt.Figure()
fig.basemap(region=[101, 108.5, 26, 29], projection="M15c", frame=True)
fig.savefig("anypath/map.png")Full error message
GPL Ghostscript 9.55.0: **** Could not open the file 'anypath/map.png'.
Error: /invalidfileaccess in --showpage--
Operand stack:
1 true
Execution stack:
%interp_exit .runexec2 --nostringval-- showpage --nostringval-- 2 %stopped_push --nostringval-- showpage showpage false 1 %stopped_push 1974 1 3 %oparray_pop 1973 1 3 %oparray_pop 1961 1 3 %oparray_pop 1817 1 3 %oparray_pop --nostringval-- %errorexec_pop .runexec2 --nostringval-- showpage --nostringval-- 2 %stopped_push --nostringval-- 1824 0 4 %oparray_pop showpage showpage
Dictionary stack:
--dict:776/1123(ro)(G)-- --dict:0/20(G)-- --dict:75/200(L)-- --dict:158/250(L)--
Current allocation mode is local
Last OS error: No such file or directory
Current file position is 24898
GPL Ghostscript 9.55.0: Unrecoverable error, exit code 1
psconvert [ERROR]: System call [gs -q -dNOPAUSE -dBATCH -dNOSAFER -dSCANCONVERTERTYPE=2 -dMaxBitmap=2147483647 -dUseFastColor=true -dGraphicsAlphaBits=2 -dTextAlphaBits=2 -sDEVICE=png16m -g1904x872 -r300 -sOutputFile='anypath/map.png' '/home/seisman/.gmt/sessions/gmt_session.90482/psconvert_90482d.eps'] returned error 256.
---------------------------------------------------------------------------
GMTCLibError Traceback (most recent call last)
Input In [6], in <cell line: 1>()
----> 1 fig.savefig("anypath/map.png")
File ~/OSS/gmt/pygmt/pygmt/figure.py:318, in Figure.savefig(self, fname, transparent, crop, anti_alias, show, **kwargs)
315 if ext == "kml":
316 kwargs["W"] = "+k"
--> 318 self.psconvert(prefix=prefix, fmt=fmt, crop=crop, **kwargs)
319 if show:
320 launch_external_viewer(fname)
File ~/OSS/gmt/pygmt/pygmt/helpers/decorators.py:585, in use_alias.<locals>.alias_decorator.<locals>.new_module(*args, **kwargs)
580 msg = (
581 f"Short-form parameter ({short_param}) is not recommended. "
582 f"Use long-form parameter '{long_alias}' instead."
583 )
584 warnings.warn(msg, category=SyntaxWarning, stacklevel=2)
--> 585 return module_func(*args, **kwargs)
File ~/OSS/gmt/pygmt/pygmt/helpers/decorators.py:725, in kwargs_to_strings.<locals>.converter.<locals>.new_module(*args, **kwargs)
723 kwargs[arg] = separators[fmt].join(f"{item}" for item in value)
724 # Execute the original function and return its output
--> 725 return module_func(*args, **kwargs)
File ~/OSS/gmt/pygmt/pygmt/figure.py:251, in Figure.psconvert(self, icc_gray, **kwargs)
248 raise GMTInvalidInput("The 'prefix' must be specified.") from err
250 with Session() as lib:
--> 251 lib.call_module(
252 module="psconvert", args=f"{prefix_arg} {build_arg_string(kwargs)}"
253 )
File ~/OSS/gmt/pygmt/pygmt/clib/session.py:506, in Session.call_module(self, module, args)
502 status = c_call_module(
503 self.session_pointer, module.encode(), mode, args.encode()
504 )
505 if status != 0:
--> 506 raise GMTCLibError(
507 f"Module '{module}' failed with status code {status}:\n{self._error_message}"
508 )
GMTCLibError: Module 'psconvert' failed with status code 79:
psconvert [ERROR]: System call [gs -q -dNOPAUSE -dBATCH -dNOSAFER -dSCANCONVERTERTYPE=2 -dMaxBitmap=2147483647 -dUseFastColor=true -dGraphicsAlphaBits=2 -dTextAlphaBits=2 -sDEVICE=png16m -g1904x872 -r300 -sOutputFile='anypath/map.png' '/home/seisman/.gmt/sessions/gmt_session.90482/psconvert_90482d.eps'] returned error 256.
System information
Please paste the output of python -c "import pygmt; pygmt.show_versions()":
PyGMT information:
version: v0.7.1.dev47+gcfc20a70
System information:
python: 3.10.5 | packaged by conda-forge | (main, Jun 14 2022, 07:04:59) [GCC 10.3.0]
executable: /home/seisman/opt/miniconda/bin/python
machine: Linux-5.18.11-200.fc36.x86_64-x86_64-with-glibc2.35
Dependency information:
numpy: 1.22.4
pandas: 1.4.2
xarray: 2022.3.0
netCDF4: 1.5.8
packaging: 21.3
geopandas: None
ghostscript: 9.55.0
gmt: 6.5.0_111fa6d_2022.08.11
GMT library information:
binary dir: /home/seisman/opt/miniconda/bin
cores: 80
grid layout: rows
library path: /home/seisman/opt/GMT-master/lib64/libgmt.so
padding: 2
plugin dir: /home/seisman/opt/GMT-master/lib64/gmt/plugins
share dir: /home/seisman/opt/GMT-master/share
version: 6.5.0