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How do I move the turtle in LOGO?
// MOVE FORWARD
FD 75
// TURN RIGHT
RT 54
// TURN LEFT
LT 21
// MOVE BACKWARD
BK 17
Check out some other turtle commands found here...
Turtle Commands
BACK ## [BK] - Move turtle back
BACKGROUND ## [BG] - Set Background color (0-15)
0 - Black
1 - White
2 - Red
3 - Cyan
4 - Purple
5 - Green
6 - Blue
7 - Yellow
8 - Orange
9 - Brown
10 - Light Red
11 - Grey 1
12 - Grey 2
13 - Light Green
14 - Light Blue
15 - Grey 3
CLEARSCREEN [CS] - Clear Screen without moving turtle
DRAW - Clear Screen and take turtle home
EACH - Tell several sprites, whose numbers are in a list, to accept commands in a second list, e.g. EACH [1 2] [SQUARE 10]
FORWARD ## [FD] - Move turtle forward
FULLSCREEN - Full graphics screen (same as pressing F5)
HEADING - Output turtle heading as a number (0-359)
HIDETURTLE [HT] - Make turtle invisible
HOME - Move turtle to center of screen pointing up
LEFT [LT] - Turn turtle left
NODRAW [ND] - Enter text mode with clear screen
NOWRAP - Prevent drawings from wrapping around screen
PENCOLOR [PC] - Change pen color
PENDOWN [PD] - Turtle leaves trail
PENUP [PU] - Turtle ceases to leave trail
RIGHT ## [RT] - Turn turtle right
SETHEADING [SETH] - Set turtle heading, e.g. SETH 180
SETSHAPE - Set the current sprite shape (0-7)
SETX Move the turtle to the specified x co-ordinates e.g. SETX 50
SETXY Move the turtle to the specified x, y co-ordinates Eg. SETXY 50 50
SETY Move the turtle to the specified y co-ordinate, e.g. SETY 50
SHAPE - Output number of current sprite's shape
SHOWTURTLE [ST] - Make turtle visible
SPLITSCREEN - Mixed graphics and text screen (same as pressing F3)
STAMPCHAR - Make the turtle stamp a character at the current location, e.g. STAMPCHAR "A
TELL - Tell designated sprite to receive commands, e.g. TELL 2
TEXTSCREEN - Use whole screen for text (same as pressing F1)
TOWARDS - Output heading for turtle to face an X,Y coordinate, e.g. TOWARDS 0 0
WRAP - Make turtle drawings wrap around the screen
XCOR - Output current x co-ordinate of turtle
YCOR - Output current y co-ordinate of turtle
ASPECT - Set verticle screen scale factor, default is 0.76
Samples taken directly from website: http://gaza.freehosting.net/logo/index.html
Logo is all about moving the turtle... you give it commands like this:
Forward 100
Right 45
You can do stuff like repeating commands too:
Repeat 8 [Forward 100 Right 45] ; Draw an octagon
(What do I win? 8-)
Whoa! Is it still around?
fd 300 // Forward
rt 90 // Right 90°
fd 300
lt 90 // Left 90°
That used to work.
I've seen a few LOGO implementations where you can use localized commands like:
NAPRZOD (FORWARD),
LEWO (LEFT),
PRAWO (RIGTH)
or even NAPRZÓD (with Polish letter Ó).
LOGO is nice language to teach kids programming in their native spoken language.
By issuing commands in the correct syntax. E.G.:
forward 100
There is only one necessary command to move the turtle. It is forward which has the mnemonic fd. When working with a robot (real) turtle as opposed to a graphics based (virtual) one, you might find that the turning commands left and right [lt & rt] move the turtle a little, accidentally.
Most implementations also allow the command backwards [bk].
When the turtle moves, it may draw a line as it goes depending on whether the pen is up or down at the time, and whether the current pen color is different from the background color.
A graphics based (virtual) turtle can also jump around the screen with setx, sety, and setxy
try: bk(back), fd(forward), ld(left turn in degrees), rt(right turn).
Related
Context:
I'm working on a device which inserted between an electronic typewriter's controller and its keyboard turns it into a serial printer/terminal.
I want it to support some of the control sequences from ECMA-48 / ISO-6429 / ANSI X3.64. (also known as ANSI escape code)
I'm having some uncertainty if I'm understanding correctly the standard, so I would like to ask to know how it should be.
It's related to the commands SLH - SET LINE HOME and SLL - SET LINE LIMIT.
For example I could have the situation that I have 1/12 inch wide characters, I want a left margin of 1 inch, and 80 columns of text.
Then I would set page home to 13 and page limit to 92.
(since character positions are counted from 1, home is the first position, limit is the last)
So far ok.
But when I already have set the home, than how should the functions:
CHA - CURSOR CHARACTER ABSOLUTE
CUP - CURSOR POSITION
HPA - CHARACTER POSITION ABSOLUTE
CPR - ACTIVE POSITION REPORT
and others related to the cursor position work?
Should they use coordinates relative to to the actual edge, or to the home position.
So in my above example if I wanted to move to column 2 of the text print area (home being 13), I should use coordinate 2 or 14?
(similarly for vertical position and page home & limit)
My understanding is that these control sequences still use the absolute coordinates.
so in my example I would have to use coordinate 14.
Is this correct?
And if it is correct, this raises some additional problems:
I would have to know where the margins are to know which horizontal and vertical offset to use when moving the cursor to absolute positions.
If a program sets the margins first, then no problem, but I a program connects to the device and does not change the margins then it does not know the offset.
(There is a way, it could send a carriage return to move to the home position and then request the ACTIVE POSITION REPORT to discover the left margin position, but it does not look like a nice solution)
What should my device do if it is requested to move to a position outside the defined home and limit?
The standard says that beyond these limits no implicit movement should happen, but this is explicit movement.
If it receives a command to move to position 1 when the home is 13 what should it do? Move to 1? Move to 13? ignore?
When it is at position 15, home is at 13 and receives command to move cursor left by 4 positions should it move by 4 to 11? move by 2 to 13? ignore?
Another problem I see is that there is a command to set page home, and page limit, but not total page height.
It is only possible to select predefined formats by PFS - PAGE FORMAT SELECTION.
But I don't see a way to select any other height.
If I want to use continuous paper with 12 inch long pages (72 lines of text at 1/6 inch line height) connected together into a long tape then I see no way to define that height so that my device can correctly keep track of its positions on the following pages. Is there a way to do it?
Looks like I had to find the answers by myself.
question 0:
Yes, it appears, that the coordinates should still be absolute.
he standard says about character positions in a line and line positions in a page and these are specified in the beginning of the document and nowhere at all is said about it being relative. Looks like the only role of line home and limit is the place where CR (and some others) returns to, and limit of where implicit movement (like advancing forward after printing a character) can go, similar for page home and page limit.
question 1:
There is no easy way for a program to recognise where the home and limit positions are. As I mentioned, requesting ACTIVE POSITION REPORT can help if this is implemented. (my devece does not support it yet).
Anyway, many programs don't recognise the concept of line home, and assume that normal character positions start from 1.
My solution to this is that after power on, the line home IS exactly at position 1, and if you want something else, you have to specify it.
This way a program can safely make this assumption.
(However after the PFS - PAGE FORMAT SELECTION command I do set the line home to 1 inch as this is what the standard proposes)
question 2:
As above, the home and limit are only a margin for implicit movements. So the cursor movement commands will move outside these limits with no problem. Only the actual page size will limit them.
question 3:
(but I didn't give it a number when asked)
DTA - DIMENSION TEXT AREA is the command for this purpose. It specifies the size of the text area limited by the actual page size, not by the home and limit positions.
I know how to draw an object arrow on the chart, which I usually do like this:
ObjectCreate(0,"prevHigh",OBJ_ARROW_DOWN,0,Time[0],High[highestCandle]);
ObjectSetInteger(0, "prevHigh", OBJPROP_COLOR, clrRed);
Now I have an indicator which (I didn't code myself and is a .ex4 file which) draws up/down arrows on the chart as seen in the image (https://imgur.com/a/8yG0suw).
How can I when for example a Magenta down arrow has been drawn and the candle (index) at which it is drawn?
Please note that the arrows not in the list of objects on the chart
Q : "How can I recognise programmatically when an up/down arrow is drawn on a chart?"
Given the facts above, your test ought evaluate the moment the CustomIndicator ( via a published / used iCustom()-call signature ) by checking it as it goes from EMPTY_VALUE to any value != EMPTY_VALUE.
Given the CustomIndicator is a closed source ( *.ex4 ) you may need to check, if it did set its own ( hidden from our sight ) value, other than a current visible EMPTY_VALUE, yet this "re-calibration" will work, after you get a few manual tests of the CustomIndicator values for bars, that do not show any arrow - like for the 2020-Apr-08 09:30 et al v/s the displayed arrows are not the MQL4-Objects on their own, they are the closed-source CustomIndicator's SetIndexStyle() / SetIndexArrow() by-products, thus not inspectable either in the Object-List, or in the *.mq4 source-code.
Yet, detectable
Using Swift methods touchBegan, touchMoved and touchEnded I save the touch points and than I draw a line using UIGraphicsGetCurrentContext() with methods beginPath(), move(to: Point), addLine(to: Point) and strokePath().
This line is repeated on 4 quadrants plus their negative values, therefore 8 lines are drawn.
Here is an example:
Example image
I save this drawing as an Image when the user taps the tick (Done green button at top-right) for later manipulations.
I wonder if it's possible to create e closed path/shape with white pixels enclosed by the black lines. I want to fill the white area with custom color when the user touches inside it.
The shape is created by user input and I have no idea how it would look like.
Would be thankful to whoever finds the time to give it's contribute.
Thank you
Maybe what you want is the "Flood Fill" algorithm, please see the article.
I'm having a little curious sense of art in programming at the moment. And I want to script my Autotouch App on my iOS to generate Pixel Art inside of another app.
I was doing this previously by typing in code to tap at the screen at one coordinate, I did this 2000+ times and it got the job done. But there should be a better, smarter way to get it done.
My test image is going to be very symetrical to make things easy.
There is a code in the Lua app that I'm using to simply tap on the screen,
tap(x, y)
But I want to set this up like:
tap({xTable}, y)
But I'm not sure if that will "tap" at each x coordinate that I've listed for the y variable.
I want to paint a pixel at one very specific coordinate, and then step 5 pixels away and paint the next one, and repeat that until the end of the line.
Is this at all possible or am I reaching beyond the language capabilities?
Edit: for some reason my phone is not blocking code when I'm asking a question, if someone sees this and wants to edit, I would be grateful.
Is this at all possible or am I reaching beyond the language capabilities?
Not even close. I recommend you read Programming in Lua.
tap({xTable}, y)
But I'm not sure if that will "tap" at each x coordinate that I've listed for the y variable.
Why are you not sure? Did you not write it? If not, you can trivially write it yourself given tap:
function tapxs(xs, y)
for i,x in ipairs(xs) do
tap(x,y)
end
end
...
tapxs({10,20,30,40}, 10) -- tap at 10,10; 20,10; 30,10; etc.
I want to paint a pixel at one very specific coordinate, and then step 5 pixels away and paint the next one, and repeat that until the end of the line.
What is "the line"? Is it purely horizontal? You could write:
function tapHorizontally(startX, maxX, y, increment)
for x=startX,maxX,increment do
tap(x,y)
end
end
...
tapHorizontally(10,100,20,5) -- tap from 10,20 to 100,20 in 5 pixel increments
Of course, that's a bizarrely specific function. You'd typically write something that takes a starting x,y and ending x,y and draws between them, so you can support horizontal, vertical, diagonal lines all with the same function, but that requires more math.
The bottom line is: Lua is a full blown, powerful, high level programming language. It could be used to write the very app you're tapping on, or the app you're using to generate taps, so the limits are going to be your knowledge of programming/algorithms/math/etc.
How to make a 2d world with fixed size, which would repeat itself when reached any side of the map?
When you reach a side of a map you see the opposite side of the map which merged togeather with this one. The idea is that if you didn't have a minimap you would not even notice the transition of map repeating itself.
I have a few ideas how to make it:
1) Keeping total of 3x3 world like these all the time which are exactly the same and updated the same way, just the players exists in only one of them.
2) Another way would be to seperate the map into smaller peaces and add them to required place when asked.
Either way it can be complicated to complete it. I remember that more thatn 10 years ago i played some game like that with soldiers following each other in a repeating wold shooting other AI soldiers.
Mostly waned to hear your thoughts about the idea and how it could be achieved. I'm coding in XNA(C#).
Another alternative is to generate noise using libnoise libraries. The beauty of this is that you can generate noise over a theoretical infinite amount of space.
Take a look at the following:
http://libnoise.sourceforge.net/tutorials/tutorial3.html#tile
There is also an XNA port of the above at: http://bigblackblock.com/tools/libnoisexna
If you end up using the XNA port, you can do something like this:
Perlin perlin = new Perlin();
perlin.Frequency = 0.5f; //height
perlin.Lacunarity = 2f; //frequency increase between octaves
perlin.OctaveCount = 5; //Number of passes
perlin.Persistence = 0.45f; //
perlin.Quality = QualityMode.High;
perlin.Seed = 8;
//Create our 2d map
Noise2D _map = new Noise2D(CHUNKSIZE_WIDTH, CHUNKSIZE_HEIGHT, perlin);
//Get a section
_map.GeneratePlanar(left, right, top, down);
GeneratePlanar is the function to call to get the sections in each direction that will connect seamlessly with the rest of your world.
If the game is tile based I think what you should do is:
Keep only one array for the game area.
Determine the visible area using modulo arithmetics over the size of the game area mod w and h where these are the width and height of the table.
E.g. if the table is 80x100 (0,0) top left coordinates with a width of 80 and height of 100 and the rect of the viewport is at (70,90) with a width of 40 and height of 20 you index with [70-79][0-29] for the x coordinate and [90-99][0-9] for the y. This can be achieved by calculating the index with the following formula:
idx = (n+i)%80 (or%100) where n is the top coordinate(x or y) for the rect and i is in the range for the width/height of the viewport.
This assumes that one step of movement moves the camera with non fractional coordinates.
So this is your second alternative in a little bit more detailed way. If you only want to repeat the terrain, you should separate the contents of the tile. In this case the contents will most likely be generated on the fly since you don't store them.
Hope this helped.