Add tool to remove transparent pixels from GCI

data/tools/README

@@ -9,6 +9,12 @@ also belong here. Other utils are in utils/.
 A program for converting campaigns to use trackplacer-format journey files.
 All mainline campaigns have already been converted; this is for lifting UMC.
 
+=== rmtrans ===
+
+Remove nearly transparent pixels from images using GIMP. It currently affects
+only one image at a time. Batch processing is available within GIMP, but it
+would be useful to expand this to skip files where the pixels did not change.
+
 === trackplacer ===
 
 A visual editor for journey tracks, the icon sequences that appear on

data/tools/rmtrans/README

@@ -0,0 +1,7 @@
+This is a GIMP script, written in python.
+See the following address to install the script:
+https://en.wikibooks.org/wiki/GIMP/Installing_Plugins#Copying_the_plugin_to_the_GIMP_plugin_directory
+
+When installed, the script will be listed under the "Colors" menu.
+
+It requires a relatively recent version of GIMP. 2.6 is too old.

data/tools/rmtrans/rmtrans.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python
+
+from gimpfu import *
+
+def rmtrans(img,tdrawable):
+	pdb.gimp_image_undo_group_start(img)
+	if pdb.gimp_selection_is_empty(img):
+		pdb.gimp_selection_all(img)
+	selection = pdb.gimp_selection_save(img)
+	pdb.gimp_selection_none(img)
+	alpha,temp,temp,temp = pdb.plug_in_decompose(img,tdrawable,"Alpha",1) # get alpha channel
+	alpha = pdb.gimp_image_get_active_layer(alpha) # turn it into a layer
+	pdb.gimp_edit_copy(alpha) 
+	pdb.gimp_floating_sel_to_layer(pdb.gimp_edit_paste(tdrawable,TRUE))
+	alpha = pdb.gimp_image_get_active_layer(img) # move alpha layer into image (copy-paste)
+	pdb.gimp_context_set_antialias(False)
+	pdb.gimp_context_set_sample_threshold(0.0) # configuration for color selection
+	for i in xrange(10):
+		pdb.gimp_image_select_color(img,CHANNEL_OP_REPLACE,alpha,(i,i,i)) # select alpha values <= 10
+		pdb.gimp_image_select_item(img,CHANNEL_OP_INTERSECT,selection) # bound it to the previously selected area (before plugin execution)
+		if not(pdb.gimp_selection_is_empty(img)):
+			pdb.gimp_edit_clear(tdrawable) # and clear it
+	print(alpha)
+	pdb.gimp_image_remove_layer(img,alpha)
+	pdb.gimp_selection_none(img)
+	pdb.gimp_image_undo_group_end(img)
+
+register(
+	"python_fu_rmtrans",
+	"Remove all pixels under a given alpha threshold.",
+	"Remove all pixels under a given alpha threshold.",
+	"Samuel Kim",
+	"Samuel Kim",
+	"2012",
+	"<Image>/Colors/Remove almost-transparent pixels",
+	"*",
+	[],
+	[],
+	rmtrans)
+
+main()