Demo/stdwin/microedit.py

   1 #! /usr/bin/env python
   2
   3 # A minimal single-window text editor using STDWIN's text objects.
   4 #
   5 # Usage: microedit file
   6 #
   7 # This is not intended as a real application but as an introduction
   8 # to STDWIN programming in Python, especially text objects.
   9 # Once you understand microedit.py, study miniedit.py to learn
  10 # about multiple windows and menus, cut and paste, etc.
  11
  12
  13 import sys
  14 import stdwin
  15 from stdwinevents import *
  16
  17
  18 # Main program
  19 #
  20 def main():
  21         #
  22         # Get the filename argument and read its contents as one very
  23         # large string.
  24         # An exception will terminate the program if there is no argument
  25         # or if the file could not be read...
  26         #
  27         filename = sys.argv[1]
  28         fp = open(filename, 'r')
  29         contents = fp.read()
  30         del fp                          # Close the file
  31         #
  32         # Create the window, using the filename as window title
  33         #
  34         window = stdwin.open(filename)
  35         #
  36         # Add a simple File menu to the window with two items
  37         #
  38         filemenu = window.menucreate('File')
  39         filemenu.additem('Save', 'S')   # Item 0 (shortcut Meta-S)
  40         filemenu.additem('Save As...')  # Item 1
  41         #
  42         # Create a text object occupying the entire window
  43         # and fill it with the file's contents
  44         #
  45         corner = window.getwinsize()    # (width, height)
  46         area = (0, 0), corner           # Rectangle as large as the window
  47         text = window.textcreate(area)
  48         text.settext(contents)
  49         del contents                    # Get rid of contents object
  50         fix_textsize(window, text)      # Set document size accordingly
  51         #
  52         # Main event loop -- stop if a close request comes in.
  53         #
  54         # STDWIN applications should regularly call stdwin.getevent()
  55         # otherwise the windows won't function as expected.
  56         #
  57         while 1:
  58                 #
  59                 # Get the next event
  60                 #
  61                 type, w, detail = e = stdwin.getevent()
  62                 #
  63                 # Event decoding switch
  64                 #
  65                 if type == WE_CLOSE:
  66                         break           # Stop (no check for saved file!)
  67                 elif type == WE_SIZE:
  68                         #
  69                         # The window was resized --
  70                         # let the text object recompute the line breaks
  71                         # and change the document size accordingly,
  72                         # so scroll bars will work
  73                         #
  74                         fix_textsize(window, text)
  75                 elif type == WE_MENU:
  76                         #
  77                         # Execute a file menu request (our only menu)
  78                         #
  79                         menu, item = detail
  80                         if item == 0:
  81                                 #
  82                                 # "Save": save to the current filename
  83                                 #
  84                                 dummy = save_file(window, text, filename)
  85                         elif item == 1:
  86                                 #
  87                                 # "Save As": ask a new filename, save to it,
  88                                 # and make it the current filename
  89                                 #
  90                                 # NB: askfile raises KeyboardInterrupt
  91                                 # if the user cancels the dialog, hence
  92                                 # the try statement
  93                                 #
  94                                 try:
  95                                         newfile = stdwin.askfile( \
  96                                                 'Save as:', filename, 1)
  97                                 except KeyboardInterrupt:
  98                                         newfile = ''
  99                                 if newfile:
 100                                         if save_file(window, text, newfile):
 101                                                 filename = newfile
 102                                                 window.settitle(filename)
 103                 elif text.event(e):
 104                         #
 105                         # The text object has handled the event.
 106                         # Fix the document size if necessary.
 107                         # Note: this sometimes fixes the size
 108                         # unnecessarily, e.g., for arrow keys.
 109                         #
 110                         if type in (WE_CHAR, WE_COMMAND):
 111                                 fix_docsize(window, text)
 112
 113
 114 # Save the window's contents to the filename.
 115 # If the open() fails, put up a warning message and return 0;
 116 # if the save succeeds, return 1.
 117 #
 118 def save_file(window, text, filename):
 119         #
 120         # Open the file for writing, handling exceptions
 121         #
 122         try:
 123                 fp = open(filename, 'w')
 124         except RuntimeError:
 125                 stdwin.message('Cannot create ' + filename)
 126                 return 0
 127         #
 128         # Get the contents of the text object as one very long string
 129         #
 130         contents = text.gettext()
 131         #
 132         # Write the contents to the file
 133         #
 134         fp.write(contents)
 135         #
 136         # The file is automatically closed when this routine returns
 137         #
 138         return 1
 139
 140
 141 # Change the size of the text object to fit in the window,
 142 # and then fix the window's document size to fit around the text object.
 143 #
 144 def fix_textsize(window, text):
 145         #
 146         # Compute a rectangle as large as the window
 147         #
 148         corner = window.getwinsize()    # (width, height)
 149         area = (0, 0), (corner)
 150         #
 151         # Move the text object to this rectangle.
 152         # Note: text.move() ignores the bottom coordinate!
 153         #
 154         text.move(area)
 155         #
 156         # Now fix the document size accordingly
 157         #
 158         fix_docsize(window, text)
 159
 160
 161 # Fix the document size, after the text has changed
 162 #
 163 def fix_docsize(window, text):
 164         #
 165         # Get the actual rectangle occupied by the text object.
 166         # This has the same left, top and right, but a different bottom.
 167         #
 168         area = text.getrect()
 169         #
 170         # Compute the true height of the text object
 171         #
 172         origin, corner = area
 173         width, height = corner
 174         #
 175         # Set the document height to the text object's height.
 176         # The width is zero since we don't want a horizontal scroll bar.
 177         #
 178         window.setdocsize(0, height)
 179
 180
 181 # Once all functions are defined, call main()
 182 #
 183 main()