Rely only into Image.convert to convert images

If a TextDocument is used as image (ie.: like in Web Illustration to SVG),
the conversion API should be from Image to prevent code duplications.

product/ERP5/Document/TextDocument.py

@@ -48,6 +48,8 @@ from Products.ERP5Type.Utils import guessEncodingFromText
 from lxml import html as etree_html
 from lxml import etree
 
+from Products.ERP5Type.ImageUtil import transformUrlToDataURI
+
 class TextDocument(CachedConvertableMixin, BaseConvertableFileMixin,
                                                             TextContent, File):
     """A TextDocument impletents IDocument, IFile, IBaseConvertable, ICachedconvertable
@@ -156,6 +158,16 @@ class TextDocument(CachedConvertableMixin, BaseConvertableFileMixin,
           filename = self.getFilename()
           if mime_type == 'text/html':
             mime_type = 'text/x-html-safe'
+          if format in VALID_IMAGE_FORMAT_LIST:
+            # Include extra parameter for image conversions
+            temp_image = self.portal_contributions.newContent(
+                                       portal_type='Image',
+                                       file=cStringIO.StringIO(),
+                                       filename=self.getId(),
+                                       temp_object=1)
+            temp_image._setData(text_content)
+            mime, result = temp_image.convert(**kw)
+          else:
             result = portal_transforms.convertToData(mime_type, text_content,
                                                    object=self, context=self,
                                                    filename=filename,
@@ -167,15 +179,6 @@ class TextDocument(CachedConvertableMixin, BaseConvertableFileMixin,
                                     'from %r to %s: %r' % 
                                     (src_mimetype, mime_type, self))
 
-          if format in VALID_IMAGE_FORMAT_LIST:
-            # do resize by temporary image
-            temp_image = self.portal_contributions.newContent(
-                                       portal_type='Image',
-                                       file=cStringIO.StringIO(),
-                                       filename=self.getId(),
-                                       temp_object=1)
-            temp_image._setData(result)
-            mime, result = temp_image.convert(**kw)
           self.setConversion(result, original_mime_type, **kw)
         else:
           mime_type, result = self.getConversion(**kw)