Add missing import. Allow TXT output to split lines based on a maximum line length value.

src/calibre/ebooks/pdb/palmdoc/reader.py

@@ -14,7 +14,7 @@ import struct
 from calibre.ebooks.compression.palmdoc import decompress_doc
 from calibre.ebooks.pdb.formatreader import FormatReader
 from calibre.ebooks.txt.processor import convert_basic, opf_writer, \
-    separate_paragraphs_single_line
+    separate_paragraphs_single_line, separate_paragraphs_print_formatted
 
 class HeaderRecord(object):
     '''

src/calibre/ebooks/pdb/ztxt/reader.py

@@ -13,7 +13,7 @@ import os, struct, zlib
 from calibre.ebooks.pdb.formatreader import FormatReader
 from calibre.ebooks.pdb.ztxt import zTXTError
 from calibre.ebooks.txt.processor import convert_basic, opf_writer, \
-    separate_paragraphs_single_line
+    separate_paragraphs_single_line, separate_paragraphs_print_formatted
 
 SUPPORTED_VERSION = (1, 40)
 

src/calibre/ebooks/txt/output.py

@@ -36,6 +36,17 @@ class TXTOutput(OutputFormatPlugin):
         OptionRecommendation(name='flush_paras',
             recommended_value=False, level=OptionRecommendation.LOW,
             help=_('Do not add a blank line between paragraphs.')),
+        OptionRecommendation(name='max_line_length',
+            recommended_value=0, level=OptionRecommendation.LOW,
+            help=_('The maximum number of characters per line. This splits on '
+            'the first space before the specified value. If no space is found '
+            'the line will be broken at the space after and will exceed the '
+            'specified value. Also, there is a minimum of 25 characters. '
+            'Use 0 to disable line splitting.')),
+        OptionRecommendation(name='force_max_line_length',
+            recommended_value=False, level=OptionRecommendation.LOW,
+            help=_('Force splitting on the max-line-length value when no space '
+            'is present. Also allows max-line-length to be below the minimum')),
         OptionRecommendation(name='indent_paras',
             recommended_value=False, level=OptionRecommendation.LOW,
             help=_('Add a tab at the beginning of each paragraph.')),

src/calibre/ebooks/txt/txtml.py

@@ -105,6 +105,40 @@ class TXTMLizer(object):
         if self.opts.indent_paras:
             text = re.sub('(?imu)^(?=.)', '\t', text)
 
+        if self.opts.max_line_length:
+            max_length = self.opts.max_line_length
+            if self.opts.max_line_length < 25 and not self.opts.force_max_line_length:
+                max_length = 25
+            short_lines = []
+            lines = text.splitlines()
+            for line in lines:
+                while len(line) > max_length:
+                    space = line.rfind(' ', 0, max_length)
+                    if space != -1:
+                        # Space was found.
+                        short_lines.append(line[:space])
+                        line = line[space + 1:]
+                    else:
+                        # Space was not found.
+                        if self.opts.force_max_line_length:
+                            # Force breaking at max_lenght.
+                            short_lines.append(line[:max_length])
+                            line = line[max_length:]
+                        else:
+                            # Look for the first space after max_length.
+                            space = line.find(' ', max_length, len(line))
+                            if space != -1:
+                                # Space was found.
+                                short_lines.append(line[:space])
+                                line = line[space + 1:]
+                            else:
+                                # No space was found cannot break line.
+                                short_lines.append(line)
+                                line = ''
+                # Add the text that was less than max_lengh to the list
+                short_lines.append(line)
+            text = '\n'.join(short_lines)
+
         return text
 
     def dump_text(self, elem, stylizer, end=''):

src/calibre/gui2/convert/txt_output.py

@@ -17,8 +17,9 @@ class PluginWidget(Widget, Ui_Form):
     HELP = _('Options specific to')+' TXT '+_('output')
 
     def __init__(self, parent, get_option, get_help, db=None, book_id=None):
-        Widget.__init__(self, parent, 'txt_output', ['newline', 'inline_toc',
+        Widget.__init__(self, parent, 'txt_output',
-        'flush_paras', 'indent_paras'])
+        ['newline', 'max_line_length', 'force_max_line_length',
+        'inline_toc', 'flush_paras', 'indent_paras'])
         self.db, self.book_id = db, book_id
         self.initialize_options(get_option, get_help, db, book_id)
 

src/calibre/gui2/convert/txt_output.ui

@@ -27,7 +27,7 @@
    <item row="0" column="1">
     <widget class="QComboBox" name="opt_newline"/>
    </item>
-   <item row="4" column="0">
+   <item row="6" column="0">
     <spacer name="verticalSpacer">
      <property name="orientation">
       <enum>Qt::Vertical</enum>
@@ -40,27 +40,47 @@
      </property>
     </spacer>
    </item>
-   <item row="1" column="0" colspan="2">
+   <item row="3" column="0" colspan="2">
     <widget class="QCheckBox" name="opt_inline_toc">
      <property name="text">
       <string>&amp;Inline TOC</string>
      </property>
     </widget>
    </item>
-   <item row="2" column="0" colspan="2">
+   <item row="4" column="0" colspan="2">
     <widget class="QCheckBox" name="opt_flush_paras">
      <property name="text">
       <string>Do not add a blank line between paragraphs.</string>
      </property>
     </widget>
    </item>
-   <item row="3" column="0" colspan="2">
+   <item row="5" column="0" colspan="2">
     <widget class="QCheckBox" name="opt_indent_paras">
      <property name="text">
       <string>Add a tab at the beginning of each paragraph</string>
      </property>
     </widget>
    </item>
+   <item row="1" column="1">
+    <widget class="QSpinBox" name="opt_max_line_length"/>
+   </item>
+   <item row="1" column="0">
+    <widget class="QLabel" name="label_2">
+     <property name="text">
+      <string>&amp;Maximum line length:</string>
+     </property>
+     <property name="buddy">
+      <cstring>opt_max_line_length</cstring>
+     </property>
+    </widget>
+   </item>
+   <item row="2" column="0" colspan="2">
+    <widget class="QCheckBox" name="opt_force_max_line_length">
+     <property name="text">
+      <string>Force maximum line lenght</string>
+     </property>
+    </widget>
+   </item>
   </layout>
  </widget>
  <resources/>