At this time the most recent commit is, I believe, the most stable.
I am not providing compiled versions of QLogo at this time. Windows and Macos systems require me to sign the binaries. (This is a good thing.) I still have yet to learn how to do that.
Please note that there are now TWO executables: logo and QLogo. The logo executable works as a standalone command-line program. The QLogo executable is a sort of GUI terminal that also provides a turtle.
QLogo is an interpreter for the Logo language written in C++ using Qt and OpenGL. It mimics (as much as I find reasonable) the UCBLogo interpreter developed by Brian Harvey at U.C. Berkeley.
Copyright (C) 2017-2023 Jason Sikes
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
The help files included in this package derive from UCBLogo under terms of the GNU General Public License as published by the Free Software Foundation, version 3.
You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.
You can find the UCBLogo Manual here:
http://people.eecs.berkeley.edu/~bh/usermanual
The differences between QLogo and UCBLogo are described in the nuances section below.
QLogo requires Qt6 and cmake.
$ cmake CMakeLists.txt
$ make
This will give you two executables:
-
"qlogo": this is the Logo interpreter that can be run from the command line.
-
"QLogo-GUI": this is the graphical user interface that runs qlogo and gives you the turtle.
There is no "make install" step yet.
-
Colors can be specified in one of three ways:
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as a palette index (0 to 100), same as UCBLogo
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as a list of 3 percentages, one for each of red, green, blue
[0 0 0]is black,[100 100 100]is white -
as a named color from the X Color Database, e.g.
whiteorlemonchiffon. The X Color database can be found here: https://en.wikipedia.org/wiki/X11_color_names
-
-
Changes in font properties (size, color, family) do not affect characters already printed. This enables multiple colors and fonts on the same console.
-
The entire Logo standard library is loaded internally and buried. There is no library directory at this time.
-
QLogo does not look for nor automatically load
STARTUP.LG. -
If
ERRACTis set and its size is greater than zero, then any errors executePAUSE. This was necessary because I couldn't find a reliable way to prevent infinite loops during error handling. -
Garbage collection is on-the-fly, meaning that memory is freed the moment a word/list/array is no longer needed.
GCand.SETSEGMENTSIZEare no-ops. -
No scunching. UCBLogo provided a scrunch to compensate for older CRT screens with non-square pixels. This enabled turtle operations to maintain consistent physical height-width.
SCRUNCHandSETSCRUNCHare no-ops. -
SAVEPICTsaves a copy of the canvas in the format given by the filename's extension. For example:SAVEPICT "MY_PICTURE.PNGwill save in PNG format. QLogo can save an image in the following formats: BMP, JPG/JPEG, PNG, PPM, XBM, and XPM -
HELPis not functional. I am moving the help text to the file system so that it can be loaded as needed. -
There is no facility yet for translation/internationalization. Yet.
SETMARGINS:
The original purpose of the command was to enable text to be visible on projectors which cut off outer boundaries of a computer screen. Projectors and monitors produced in the last few years show all of the computer screen. In addition, QLogo is a windowed application so an instructor or presentor can move the window to a different position.
FILL:
Two reasons: One of the user interface principles is that the canvas should be device resolution-independent. That means when the QLogo window is resized or the separator between the text and the graphics is moved the graphics will be redrawn with the new dimensions. The Flood Fill algorithm depends on specific pixels which means that the display can change dramatically depending on the size of the canvas. The other reason is that the Flood Fill algorithm can slow down window resizing. Use FILLED instead.
LOADPICT:
This will be implemented soon.
EPSPICT:
This will be replaced by SVGPICT.
CSLSLOAD:
Not implemented yet.
SETCSLSLOC:
Not implemented yet.
SETEDITOR:
QLogo uses a built-in editor. If you run the logo program on the command line, no editor is available.
SETLIBLOC:
The QLogo library is stored internally.
SETHELPLOC:
Not implemented yet.
SETTEMPLOC:
QLogo doesn't create temporary files at this time.
COMMANDLINE:
Not implemented yet.
REDEFP:
Qt has strong support for internationalization, but QLogo is not designed at this time to take advantage of that. Internationalization will be supported soon.
USEALTERNATENAMES:
Ditto.
ALLFONTS:
Returns a list of all the fonts available on your system.
CURSORINSERT:
Sets cursor to insert mode in QLogo. This is the default.
CURSOROVERWRITE:
Sets cursor to overwrite mode in QLogo.
CURSORMODE:
Outputs either INSERT or OVERWRITE.
STANDOUT:
This works in QLogo by switching the font's foreground and background colors. It isn't implemented for text terminals.
BOUNDS:
Outputs a list of two numbers giving the maximum bounds (x,y)
of the canvas. e.g. bounds of [350 150] means that the
turtle is visible if its X-coordinate is between -350 and 350
and its Y-coordinate is between -150 and 150. The coordinate
[0, 0] is always in the center. See SETBOUNDS
SETBOUNDS:
Takes two integers and sets outer bounds of the canvas.
See BOUNDS.
MATRIX:
This exists for debugging and may be removed. Outputs a list of four lists, each sublist contains four numbers. This is the matrix that represents the current turtle state. In row-major order.