[gimp] Export image histogram to text file

[João Sebastião de Oliveira Bueno Calligaris <jsbueno src gnome org>]

commit 1ad14fa6d6876189cfbf38b768971e736b122f04
Author: João S. O. Bueno <gwidion gmail com>
Date:   Wed Jan 8 10:41:52 2014 -0200

    Export image histogram to text file

 plug-ins/pygimp/plug-ins/histogram-export.py |  113 ++++++++++++++++++++++++++
 1 files changed, 113 insertions(+), 0 deletions(-)
---
diff --git a/plug-ins/pygimp/plug-ins/histogram-export.py b/plug-ins/pygimp/plug-ins/histogram-export.py
new file mode 100755
index 0000000..4045a6d
--- /dev/null
+++ b/plug-ins/pygimp/plug-ins/histogram-export.py
@@ -0,0 +1,113 @@
+#!/usr/bin/env python
+#coding: utf-8
+
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+Exports the image histogram to a text file,
+so that it can be used by other programs
+and loaded into spreadsheets.
+
+The resulting file is a CSV file (Comma Separated
+Values), which can be imported
+directly in most spreadsheet programs.
+
+The first two collums are the bucket boundaries,
+followed by the selected columns. The histogram
+refers to the selected image area, and
+can use either Sample Average data or data
+from the current drawable only.;
+
+The output is in "weighted pixels" - meaning
+all fully transparent pixels are not counted.
+
+Check the gimp-histogram call
+"""
+
+
+from gimpfu import *
+import csv
+import gettext
+
+
+gettext.install("gimp20-python", gimp.locale_directory, unicode=True)
+
+def histogram_export(img, drw, filename,
+                     bucket_size, sample_average, output_format):
+    if sample_average:
+        new_img = pdb.gimp_image_duplicate(img)
+        drw = pdb.gimp_image_merge_visible_layers(new_img, CLIP_TO_IMAGE)
+    # TODO: grey images, alpha and non alpha images.
+    channels_txt = ["Value"] 
+    channels_gimp = [HISTOGRAM_VALUE]
+    if drw.is_rgb:
+        channels_txt += ["Red", "Green", "Blue"]
+        channels_gimp += [HISTOGRAM_RED, HISTOGRAM_GREEN, HISTOGRAM_BLUE]
+    if drw.has_alpha:
+        channels_txt += ["Alpha"]
+        channels_gimp += [HISTOGRAM_ALPHA]
+    with open(filename, "wt") as hfile:
+        writer = csv.writer(hfile)
+        #headers:
+        writer.writerow(["Range start"] + channels_txt)
+
+        # FIXME: Will need a specialized 'range' for FP color numbers
+        for start_range in range(0, 256, int(bucket_size)):
+            row = [start_range]
+            for channel in channels_gimp:
+                result = pdb.gimp_histogram(
+                             drw, channel,
+                             start_range,
+                             min(start_range + bucket_size, 255)
+                            )
+                if output_format == "pixel count":
+                    count = result[4]
+                else:
+                    count = (result[4] / result[3]) if result[3] else 0
+                    if output_format == "percent":
+                        count = "%.2f%%" % (count * 100)
+                row.append(str(count))
+            writer.writerow(row)
+    if sample_average:
+        pdb.gimp_image_delete(new_img)
+
+register(
+    "histogram-export",
+    N_("Exports the image histogram to a text file (CSV)"),
+    globals()["__doc__"], # This includes the docstring, on the top of the file
+    "João S. O. Bueno",
+    "João S. O. Bueno, 2014",
+    "2014",
+    N_("_Export histogram..."),
+    "*",
+    [(PF_IMAGE,  "img", _("_Image"), None),
+     (PF_DRAWABLE, "drw", _("_Drawable"), None),
+     (PF_FILE, "filename", _("Histogram _File"), ""),
+     (PF_FLOAT, "bucket_size", _("_Bucket Size"), 1.0),
+     (PF_BOOL, "sample_average", _("Sample _Average"), False),
+     (PF_RADIO, "output_format", _("Output format"), "pixel count",
+            ((_("Pixel count"), "pixel count"),
+             (_("Normalized"), "normalized"),
+             (_("Percent"), "percent"),
+            )
+     )
+    ],
+    [],
+    histogram_export,
+    menu="<Image>/Colors",
+    domain=("gimp20-python", gimp.locale_directory)
+    )
+
+main()
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