[gimp] openraster: Implements exporting and loading group layers.

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

commit 0fad7bb1262e248c26617a29018c50bd493ae3b8
Author: Joao S. O. Bueno <gwidion gmail com>
Date:   Thu Feb 26 11:29:07 2015 -0300

    openraster: Implements exporting and loading group layers.
    
    This preserves the layer structure and
    brings it in pair to MyPaint development branch
    (allowing interchange of .ora files with group layers).
    
    Previous behavior on load was oppening all
    sub-layers in a flat-space, with no groups,
    and flatten layer groups on export.
    
    The implemented behavior accords to the
    openraster spec.

 plug-ins/pygimp/plug-ins/file-openraster.py |  154 +++++++++++++++++++++------
 1 files changed, 121 insertions(+), 33 deletions(-)
---
diff --git a/plug-ins/pygimp/plug-ins/file-openraster.py b/plug-ins/pygimp/plug-ins/file-openraster.py
index 424ebfc..135b9b4 100755
--- a/plug-ins/pygimp/plug-ins/file-openraster.py
+++ b/plug-ins/pygimp/plug-ins/file-openraster.py
@@ -16,8 +16,12 @@
 import os, sys, tempfile, zipfile
 import xml.etree.ElementTree as ET
 
+
 from gimpfu import *
 
+NESTED_STACK_END = object()
+
+
 layermodes_map = {
     "svg:src-over": NORMAL_MODE,
     "svg:multiply": MULTIPLY_MODE,
@@ -62,6 +66,17 @@ def get_layer_attributes(layer):
 
     return path, name, x, y, opac, visible, layer_mode
 
+def get_group_layer_attributes(layer):
+    a = layer.attrib
+    name = a.get('name', '')
+    x = int(a.get('x', '0'))
+    y = int(a.get('y', '0'))
+    opac = float(a.get('opacity', '1.0'))
+    visible = a.get('visibility', 'visible') != 'hidden'
+    m = a.get('composite-op', 'svg:src-over')
+    layer_mode = layermodes_map.get(m, NORMAL_MODE)
+
+    return name, x, y, opac, visible, layer_mode
 
 def thumbnail_ora(filename, thumb_size):
     # FIXME: Untested. Does not seem to be used at all? should be run
@@ -89,7 +104,7 @@ def save_ora(img, drawable, filename, raw_filename):
         # work around a permission bug in the zipfile library:
         # http://bugs.python.org/issue3394
         zi = zipfile.ZipInfo(fname)
-        zi.external_attr = 0100644 << 16
+        zi.external_attr = int("100644", 8) << 16
         zfile.writestr(zi, data)
 
     tempdir = tempfile.mkdtemp('gimp-plugin-file-openraster')
@@ -126,11 +141,11 @@ def save_ora(img, drawable, filename, raw_filename):
         orafile.write(tmp, path)
         os.remove(tmp)
 
-    def add_layer(x, y, opac, gimp_layer, path, visible=True):
+    def add_layer(parent, x, y, opac, gimp_layer, path, visible=True):
         store_layer(img, gimp_layer, path)
         # create layer attributes
         layer = ET.Element('layer')
-        stack.append(layer)
+        parent.append(layer)
         a = layer.attrib
         a['src'] = path
         a['name'] = gimp_layer.name
@@ -141,11 +156,59 @@ def save_ora(img, drawable, filename, raw_filename):
         a['composite-op'] = reverse_map(layermodes_map).get(gimp_layer.mode, 'svg:src-over')
         return layer
 
+    def add_group_layer(parent, x, y, opac, gimp_layer, visible=True):
+        # create layer attributes
+        group_layer = ET.Element('stack')
+        parent.append(group_layer)
+        a = group_layer.attrib
+        a['name'] = gimp_layer.name
+        if x:
+            a['x'] = str(x)
+        if y:
+            a['y'] = str(y)
+        a['opacity'] = str(opac)
+        a['visibility'] = 'visible' if visible else 'hidden'
+        a['composite-op'] = reverse_map(layermodes_map).get(gimp_layer.mode, 'svg:src-over')
+        return group_layer
+
+
+    def enumerate_layers(group):
+        for layer in group.layers:
+            if not isinstance(layer, gimp.GroupLayer):
+                yield layer
+            else:
+                yield layer
+                for sublayer in enumerate_layers(layer):
+                    yield sublayer
+                yield NESTED_STACK_END
+
     # save layers
-    for i, lay in enumerate(img.layers):
+    parent_groups = []
+    i = 0
+    for lay in enumerate_layers(img):
+        if lay is NESTED_STACK_END:
+            parent_groups.pop()
+            continue
         x, y = lay.offsets
         opac = lay.opacity / 100.0 # needs to be between 0.0 and 1.0
-        add_layer(x, y, opac, lay, 'data/%03d.png' % i, lay.visible)
+
+        if not parent_groups:
+            path_name = 'data/{:03d}.png'.format(i)
+            i += 1
+        else:
+            path_name = 'data/{}-{:03d}.png'.format(
+                parent_groups[-1][1], parent_groups[-1][2])
+            parent_groups[-1][2] += 1
+
+        parent = stack if not parent_groups else parent_groups[-1][0]
+
+        if isinstance(lay, gimp.GroupLayer):
+            group = add_group_layer(parent, x, y, opac, lay, lay.visible)
+            group_path = ("{:03d}".format(i) if not parent_groups else
+                parent_groups[-1][1] + "-{:03d}".format(parent_groups[-1][2]))
+            parent_groups.append([group, group_path , 0])
+        else:
+            add_layer(parent, x, y, opac, lay, path_name, lay.visible)
 
     # save thumbnail
     w, h = img.width, img.height
@@ -171,6 +234,7 @@ def save_ora(img, drawable, filename, raw_filename):
         os.remove(filename) # win32 needs that
     os.rename(filename + tmp_sufix, filename)
 
+
 def load_ora(filename, raw_filename):
     tempdir = tempfile.mkdtemp('gimp-plugin-file-openraster')
     original_name = filename
@@ -188,47 +252,71 @@ def load_ora(filename, raw_filename):
     img.filename = filename
 
     def get_layers(root):
-        """returns a flattened list of all layers under root"""
-        res = []
+        """iterates over layers and nested stacks"""
         for item in root:
             if item.tag == 'layer':
-                res.append(item)
+                yield item
             elif item.tag == 'stack':
-                res += get_layers(item)
-        return res
+                yield item
+                for subitem in get_layers(item):
+                    yield subitem
+                yield NESTED_STACK_END
+
+    parent_groups = []
 
-    for layer_no, layer in enumerate(get_layers(stack)):
-        path, name, x, y, opac, visible, layer_mode = get_layer_attributes(layer)
+    layer_no = 0
+    for item in get_layers(stack):
 
-        if not path.lower().endswith('.png'):
+        if item is NESTED_STACK_END:
+            parent_groups.pop()
             continue
-        if not name:
-            # use the filename without extension as name
-            n = os.path.basename(path)
-            name = os.path.splitext(n)[0]
 
-        # create temp file. Needed because gimp cannot load files from inside a zip file
-        tmp = os.path.join(tempdir, 'tmp.png')
-        f = open(tmp, 'wb')
-        try:
-            data = orafile.read(path)
-        except KeyError:
-            # support for bad zip files (saved by old versions of this plugin)
-            data = orafile.read(path.encode('utf-8'))
-            print 'WARNING: bad OpenRaster ZIP file. There is an utf-8 encoded filename that does not have 
the utf-8 flag set:', repr(path)
-        f.write(data)
-        f.close()
-
-        # import layer, set attributes and add to image
-        gimp_layer = pdb['gimp-file-load-layer'](img, tmp)
+        if item.tag == 'stack':
+            name, x, y, opac, visible, layer_mode = get_group_layer_attributes(item)
+            gimp_layer = gimp.GroupLayer(img)
+
+        else:
+            path, name, x, y, opac, visible, layer_mode = get_layer_attributes(item)
+
+            if not path.lower().endswith('.png'):
+                continue
+            if not name:
+                # use the filename without extension as name
+                n = os.path.basename(path)
+                name = os.path.splitext(n)[0]
+
+            # create temp file. Needed because gimp cannot load files from inside a zip file
+            tmp = os.path.join(tempdir, 'tmp.png')
+            f = open(tmp, 'wb')
+            try:
+                data = orafile.read(path)
+            except KeyError:
+                # support for bad zip files (saved by old versions of this plugin)
+                data = orafile.read(path.encode('utf-8'))
+                print 'WARNING: bad OpenRaster ZIP file. There is an utf-8 encoded filename that does not 
have the utf-8 flag set:', repr(path)
+            f.write(data)
+            f.close()
+
+            # import layer, set attributes and add to image
+            gimp_layer = pdb['gimp-file-load-layer'](img, tmp)
+            os.remove(tmp)
         gimp_layer.name = name
         gimp_layer.mode = layer_mode
         gimp_layer.set_offsets(x, y)  # move to correct position
         gimp_layer.opacity = opac * 100  # a float between 0 and 100
         gimp_layer.visible = visible
-        img.add_layer(gimp_layer, layer_no)
 
-        os.remove(tmp)
+        pdb.gimp_image_insert_layer(img, gimp_layer,
+                                    parent_groups[-1][0] if parent_groups else None,
+                                    parent_groups[-1][1] if parent_groups else layer_no)
+        if parent_groups:
+            parent_groups[-1][1] += 1
+        else:
+            layer_no += 1
+
+        if isinstance(gimp_layer, gimp.GroupLayer):
+            parent_groups.append([gimp_layer, 0])
+
     os.rmdir(tempdir)
 
     return img