Doc-es: update Included/Generating.

[lilypond.git] / Documentation / contributor / regressions.itexi

diff --git a/Documentation/contributor/regressions.itexi b/Documentation/contributor/regressions.itexi
index 5de3f8aa918572a3cbe34e9b0b6ec1fda61e2b97..365582e87f7a8beef00a6e437f67d7b005fba98a 100644 (file)
--- a/Documentation/contributor/regressions.itexi
+++ b/Documentation/contributor/regressions.itexi
@@ -7,6 +7,7 @@
 * Precompiled regression tests::
 * Compiling regression tests::
 * Regtest comparison::
 * Precompiled regression tests::
 * Compiling regression tests::
 * Regtest comparison::

+* Pixel-based regtest comparison::

 * Finding the cause of a regression::
 * Memory and coverage tests::
 * MusicXML tests::
 * Finding the cause of a regression::
 * Memory and coverage tests::
 * MusicXML tests::


@@ -99,8 +100,20 @@ verify that the regression tests have, in fact, run.}
 
 The test comparison shows all of the changes that occurred between
 the current release and the prior release.  Each test that has a
 
 The test comparison shows all of the changes that occurred between
 the current release and the prior release.  Each test that has a

-significant difference in output is displayed, with the old
-version on the left and the new version on the right.
+significant (noticeable) difference in output is displayed, with
+the old version on the left and the new version on the right.
+
+Some of the small changes can be ignored (slightly different slur
+shapes, small variations in note spacing), but this is not always
+the case: sometimes even the smallest change means that something
+is wrong.  To help in distinguishing these cases, we use bigger
+staff size when small differences matter.
+
+Staff size 30 generally means "pay extra attention to details".
+Staff size 40 (two times bigger than default size) or more means
+that the regtest @strong{is} about the details.
+
+Staff size smaller than default doesn't mean anything.

 
 Regression tests whose output is the same for both versions are
 not shown in the test comparison.
 
 Regression tests whose output is the same for both versions are
 not shown in the test comparison.


@@ -123,6 +136,11 @@ something is suspicious!
 @item
 Profile files: give information about
 TODO?  I don't know what they're for.
 @item
 Profile files: give information about
 TODO?  I don't know what they're for.

+Apparently they give some information about CPU usage.  If you got
+tons of changes in cell counts, this probably means that you compiled
+@code{make test-baseline} with a different amount of CPU threads than
+@code{make check}. Try redoing tests from scratch with the same
+number of threads each time -- see @ref{Saving time with the -j option}.

 
 @end itemize
 
 
 @end itemize
 


@@ -197,7 +215,7 @@ Run @code{make} with current git master without any of your changes.
 
 @item
 Before making changes to the code, establish a baseline for the comparison by
 
 @item
 Before making changes to the code, establish a baseline for the comparison by

-going to the @file{lilypond-git/build/} directory and running:
+going to the @file{$LILYPOND_GIT/build/} directory and running:

 
 @example
 make test-baseline
 
 @example
 make test-baseline


@@ -281,6 +299,58 @@ and want to do regtests comparison for all of them, you can
 @code{make test-clean}, @code{make} and @code{make check} it without doing
 @code{make test-baseline} again.}
 
 @code{make test-clean}, @code{make} and @code{make check} it without doing
 @code{make test-baseline} again.}
 

+@node Pixel-based regtest comparison
+@section Pixel-based regtest comparison
+
+As an alternative to the @code{make test} method for regtest checking (which
+relies upon @code{.signature} files created by a LilyPond run and which describe
+the placing of grobs) there is a script which compares the output of two
+LilyPond versions pixel-by-pixel.  To use this, start by checking out the
+version of LilyPond you want to use as a baseline, and run @code{make}.  Then,
+do the following:
+
+@example
+cd $LILYPOND_GIT/scripts/auxiliar/
+./make-regtest-pngs.sh -j9 -o
+@end example
+
+The @code{-j9} option tells the script to use 9 CPUs to create the
+images - change this to your own CPU count+1.  @code{-o} means this is the "old"
+version.  This will create images of all the regtests in
+
+@example
+$LILYPOND_BUILD_DIR/out-png-check/old-regtest-results/
+@end example
+
+Now checkout the version you want to compare with the baseline.  Run
+@code{make} again to recreate the LilyPond binary.  Then, do the following:
+
+@example
+cd $LILYPOND_GIT/scripts/auxiliar/
+./make-regtest-pngs.sh -j9 -n
+@end example
+
+The @code{-n} option tells the script to make a "new" version of the
+images.  They are created in
+
+@example
+$LILYPOND_BUILD_DIR/out-png-check/new-regtest-results/
+@end example
+
+Once the new images have been created, the script compares the old images with
+the new ones pixel-by-pixel and prints a list of the different images to the
+terminal, together with a count of how many differences were found.  The
+results of the checks are in
+
+@example
+$LILYPOND_BUILD_DIR/out-png-check/regtest-diffs/
+@end example
+
+To check for differences, browse that directory with an image
+viewer.  Differences are shown in red.  Be aware that some images with complex
+fonts or spacing annotations always display a few minor differences.  These can
+safely be ignored.
+

 
 @node Finding the cause of a regression
 @section Finding the cause of a regression
 
 @node Finding the cause of a regression
 @section Finding the cause of a regression