Changes

The json encoding of a repeat 4 forward 100 right 90 project:

The json encoding of a repeat 4 forward 100 right 90 project:

                                        

                                        

  [[0,"repeat",331,158,[null,1,2,null]],[1,["number","4"],417,167,[0,null]],[2,"forward",426,207,[0,3,4]],[3,["number","100"],500,216,[2,null]],[4,"right",426,246,[2,5,null]],[5,["number","90"],500,255,[4,null]],[-1,"turtle",0,0,0,0,50,5]]

  [

  [0,"repeat",331,158,[null,1,2,null]],

  [1,["number","4"],417,167,[0,null]],

  [2,"forward",426,207,[0,3,4]],

  [3,["number","100"],500,216,[2,null]],

  [4,"right",426,246,[2,5,null]],

  [5,["number","90"],500,255,[4,null]],

  [-1,"turtle",0,0,0,0,50,5]

]

The basic structure of the encoding is a list of lists, where each block has these elements:

The basic structure of the encoding is a list of lists, where each block has these elements:

# block number

# block number

# block name or [block name, block value]

# block name or [block name, block value]

# x position (depreciated)

# x position (deprecated)

# y position (depreciated)

# y position (deprecated)

# list of connections to other blocks

# list of connections to other blocks

# pen shade

# pen shade

# pen width

# pen width

== Modifying Turtle Art ==

== Modifying Turtle Art ==

'''Note:''' As of Version 106, there is also support for plugins. If you can use the plugin mechanism to add support for additional devices, e.g., Arduino, or for making modifications such as are described below without making changes to the standard code base. (The advantage to the latter is that your changes will remain intact even after you upgrade to a newer version.)

'''Note:''' As of Version 106, there is also support for plugins. If you can use the plugin mechanism to add support for additional devices, e.g., Arduino, or for making modifications such as are described below without making changes to the standard code base. (The advantage to the latter is that your changes will remain intact even after you upgrade to a newer version.)

taconstants.py contains the constants that by-in-large determine the behavior of Turtle Art. Notably, the block palettes are defined below. If you want to add a new block to Turtle Art, it is generally a matter of modifying some tables below and then adding the primitive to talogo.py. For example, if we want to add a new turtle command, 'uturn', we'd make the following changes:

The tabasics.py file contains the constants that by-in-large determine the behavior of Turtle Art. Notably, the block palettes are defined

 

below. If you want to add a new block to Turtle Art, you could simply add a block of code to that file or to turtle_block_plugin.py,

which contains additional blocks. (Even better, write your own plugin!!)

 

 

 

 

note that the name is an array, as some blocks contain multiple

 

...

    'uturn':[_('u-turn')],

 

(4) and a help-menu entry:

     palette = make_palette('mypalette',  # the name of your palette

     'uturn':_('change the heading of the turtle 180 degrees'),

                          help_string=_('Palette of my custom commands'))

(5) Next, we need to define it as a primitive for the Logo command

For example, if we want to add a new turtle command, 'uturn', we'd use the

parser (generally just the same name):

                      label=_('u turn'),  # the label for the block

                      help_string=_('turns the turtle 180 degrees'))

Next, you need to define what your block will do. def_prim takes 3 arguments: the primitive name, the number of arguments—0 in this case—and the function to call—in this case, the canvas.seth function to set the heading.

...

    'uturn':'uturn',

...

(6) Since there are no default arguments, we don't need to do anything

    self.tw.lc.def_prim('uturn', 0,

else here. But we do need to define the actual function in talogo.py

        lambda self: self.tw.canvas.seth(self.tw.canvas.heading + 180))

That's it. When you next run Turtle Art, you will have a 'uturn' block on the 'mypalette' palette.

...

    'uturn':[0, lambda self: self.tw.canvas.seth(self.tw.canvas.heading+180)],

...

That's it. When you next run Turtle Art, you will have a 'uturn' block

on the Turtle Palette.

mypaletteoff.svg and mypaletteon.svg, where 'mypalette' is the same

string as the entry you used in instantiating the Palette class. Note

the default icon size for Sugar toolbars.)

Adding a new palette is simply a matter of: (1) adding an additional entry to PALETTE_NAMES; (2) new list of blocks to PALETTES; and (3) an additional entry in COLORS. However you will have to: (4) create icons for the palette-selector buttons. These are kept in the icons subdirectory. You need two icons: yourpalettenameoff.svg and yourpalettenameon.svg, where yourpalettename is the same string as the entry you added to the PALETTE_NAMES list. Note that the icons should be the same size (55x55) as the others. This is the default icon size for Sugar toolbars.

In Spanish: http://valentinbasel.fedorapeople.org/pdfs/turtle_art.pdf