Description Usage Arguments Details Value Author(s) See Also Examples
Functions to generate a scene using the graphics package,
reproduce the scene using grid.echo()
, test whether the
two results are identical, and report on any differences.
1 2 3 4 | plotdiff(expr, label, dev = "pdf",
antialias = TRUE, density = 100, width = 7, height = 7)
plotdiffInit()
plotdiffResult(warn = FALSE)
|
expr |
An expression that draws something using the graphics package. |
label |
A character value that is used to label files generated during testing. |
dev |
The graphics device used for drawing and echoing. Currently can only be
either |
antialias |
A logical value indicating whether to perform antialiasing when converting from PDF to PNG. |
density |
A numeric value indicating the resolution (dpi) to use when converting from PDF to PNG. |
width, height |
Numeric values indicating the size of the device to test on. |
warn |
A logical value indicating whether non-identical output should produce a warning or an error. |
In default usage, plotdiff()
is used to generate two PDF
files, one using the original expression and the other from a call
to grid.echo()
. The PDF files are then converted to PNG
files and the PNG files are compared (using ImageMagick). If
there are any differences, the
comparison generates a further PNG file that shows the differences.
All files are currently generated in the current working directory.
Text messages are also generated by plotdiff()
whenever a
difference is found, but those messages are stored up rather than
printed immediately.
The plotdiffResult()
function prints out all messages
since the last call to plotdiffInit()
.
Standard usage involves calling plotdiffInit()
, followed by
one or more plotdiff()
calls, then finally a call to
plotdiffResult()
.
Examples of the usage of these functions are provided in the numerous
test scripts in the test-scripts
directory of the package.
All functions are run for their side effects.
In the case of plotdiff()
, the generation of PDF and PNG files
and the accumulation of differences about messages.
In the case of plotdiffResult()
, a print out of the accumulated
messages, plus possibly either an error or warning.
Paul Murrell
1 2 3 4 | ## Not run:
plotdiff(expression(plot(1)), "plot")
## End(Not run)
|
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