3 questions in my code

[Binary1248]

Trying to learn some simple graphics based on code from examples: The attached prgm creats lines and random dots.
Liberty V4.5.1 version
The listing has 3 line numbers to help where my questions are. 10, 20, 30
#10 How can I code a button in the #mywindow1 to allow keyboard action input ?
#20 What does the term "down" in this statement, and what other terms work ?
#30 Is there a way to print inside #mywindow1 directly on the window ?
.
Now I need to go back and see how to add attachment. 
Fractels003.bas (2.72 KB)
.
Well that seems strange, so here is the code: This got reformatted, not pretty now ?

'Highly modified, original coolFractal.bas contributed by Rod

'amended by klaactu

'Modified for PEH as learning tool in graphics

' #1 is the screen name, renamed to hjk1 just for test



nomainwin



WindowWidth = DisplayWidth

WindowHeight = DisplayHeight

'+++ Not used for now, useful later +++++++++++++++++++++++++++++++++

UpperLeftX = int((DisplayWidth-WindowWidth)/2)

UpperLeftY = int((DisplayHeight-WindowHeight)/2)

midx=int(WindowWidth/2)

midy=int(WindowHeight/2)

'++++++++++++++++++++++++++++++++++++++++++++++++++++++



'========== revisit later to get working button =====================================

10 button #mywindow1, "Clear", [clear], LR, 50, 10

'$$$$Not neede for now, $$$$$ jumps or calls label Clear, cleans any previous screen, WHAT is LR, 50, 10

'BUTTON #handle.ext, "label", returnVar, corner, x, y {, width, height}

'====================================================================================

open "Just my header name Fractzals002" for graphics_nsb as #mywindow1

#mywindow1 "trapclose [quit]"   'this sends the prgm to exit on window closing



lpcnt=1  'init loop count for multiple line draws



[clear]

20 #mywindow1 "down ; fill black"

' What is 'down' and what other cmds instead of down,  I understand the fill

' color black, or color red, or others

30 'print #mywindow1.txtEdit, " 5 sec delay now"

'print #mywindow1 " 5 sec delay now"

  'Hmm, print cmd doesn't work in graphics mode ?

'for j=1 to 10000  'about 5 sec delay

' for k= 1 to 300

' next k

'next j

'

[draw]



'calculate and draw the points

lpcnt=lpcnt+10

   scan   'check for kb inputs ??? kb interrupt ???'

  for j= 1 to 400

   xp=1+j+lpcnt

   yp=1+j

      'delay between dots

       for delayx = 1 to 100

       next delayx

    #mywindow1 "color "; "red"

    #mywindow1 "set ";xp;" ";yp

  next j

'NOW DO A GREEN (or other color) line

  for j= 1 to 800

  xp=lpcnt+j  'add offset for multiple draws

  yp=700-j

  #mywindow1 "color "; "green"

  #mywindow1 "set ";xp;" ";yp

       for delayx = 1 to 100

       next delayx

  next j

'Now draw horz line across top

  'NOW DO A Blue (or other color) line

  for j= 1 to 800

  xp=j 'add offset for multiple draws, later

  yp=lpcnt

  #mywindow1 "color "; "yellow"

  #mywindow1 "set ";xp;" ";yp

       for delayx = 1 to 100

       next delayx

  next j

'random points now, as new lines are drawn, the old lines will begin to fad as

' random seq writes over them point by point

 for a = 1 to 100000  'lots of points of lights or we will never see them, they are tiny !

   xp= int(rnd(1)*1000) '+ 1

   yp= int(rnd(1)*1000) '+ 1

   #mywindow1 "color "; "blue"

   #mywindow1 "set ";xp;" ";yp

 next a



goto [draw]



[quit]

close #mywindow1

end








.
.

[honkytonk]

[clear]
#mywindow1 "down ; fill black"
wait
-----------
"down" it is the lowering of the pen on the paper (essential for drawing).
There is also: "when leftbutton Down"
in association with
mx=MouseX: my=MouseY
Which gives the click position
------------
For delay:
gosub [pause]
.......
[pause]
timer temp, [temps] 'temp en millisecondes
wait
[temps]
timer 0
return

[B+]

Paul here is the perfect pause SUB

sub pause mil   'tsh version has scan built-in
   t0 = time$("ms")
   while time$("ms") < t0 + mil : scan : wend  'scans so if you quit on pause no problem
end sub



Store it at the end of your code where SUBs and FUNCTIONs go. When you need to pause or delay
CALL pause 2000 ' for 2 secs
CALL pause 200 ' for .2 secs
CALL pause 20 ' for .02 secs

[Rod]

This got reformatted, not pretty now ?

If you are posting code use the [c] tags but also be very sure you are on the Post Quick Reply box or the BBCode pane if editing. If you use the preview pane the code will be double spaced.

Looping timers are not my favorite. They make the program unresponsive. Just do timer x,[branch] then wait. Then if something interrupts it can be handled. If you are looping nothing else gets a look in. Scan helps but your program is still doing nothing else while you pause. It could be doing a stack of drawing or computing while you pause.

If you can find the Graphics Command list in the help file there are hundreds of graphic commands that will draw or react to keyboard or mouse events. Orchestrating these events provides massive power over your program flow. Like the Timer, Events need managed off and on when needed.

[tsh73]

#10
10 button #mywindow1, "Clear", [clear], LR, 50, 10
puts upuir button too low, likely under taskbar
(you asked WindowHeight = DisplayHeight, it does not account for taskbar)

If you do
open "Just my header name Fractzals002" for graphics_nsb_fs as #mywindow1
instead of
graphics_nsb
then
10 button #mywindow1, "Clear", [clear], LR, 50, 10
will work as expected.

#20
as was said, you will not get any drawing until you put pen down

#30
sure
we way is
print #mywindow1, "\";"anything to print"
(or you could use "|" instead of "\"
- without it, any repeating "\" will act as a newline)

BUT
it prints to past place your drawing pen end to
(or placed with
print #handle, "place Xnumber Ynumber"
)
And if you print as a first thing (no draw), initial position will be (0,0) - upper left
And print will go ABOVE THAT

So simplest thing is make a new line with extra "\"
print #mywindow1, "\\";" 5 sec delay now"

[Binary1248]

Thanks honkytonk, B+, Rod it all helps.
As to loop timers, yes they are sloppy and crude and I will use your suggestions, but when writing and testing I often temporarily fall back to my early days of coding.
Rod, I am still trying to understand your method of showing code. I used the boxed C next to the Quote button, but I guess none of those are appropriate. When editing I got close spaced lines, various colors of text that make the code easier to read. Example the three line numbers I referenced to my questions were bright red and stood out. I think I also tried "Add Attachment" button but the pretty formatting the editor presents was lost.
  I will try some more methods of attaching code after I look thru the treads and see how others are posting. Still learning at 81 years, so be patient. 
.
Thanks tsh83, your post showed up just after I posted the above. Will try all your suggestions.

[Binary1248]

OK, the three code items I asked about now work and will be implemented if needed.
As to posting code, I guess the nice colors shown in the Liberty editor just don't transfer over, but the line spacing can be close as Rod explained.
Many thanks guys. Now back to working on code I really don't need, but it is a brain massage that I need.
Paul

[B+]

Trying to make some sense with paulironhorse code I ran into a problem myself.

The following code works fine without the button, press <spacebar> and screen clears, press <enter> and draw redraws screen works fine until you try the button. The first time it clears and you can redraw with <enter> anytime after that it bugs out with error about finding clearScreen.

nomainwin

'fix work area so easily fits inside screen
WindowWidth = 700 +8  '700 pixels work area plus border this assumes no menu
WindowHeight = 700 + 32 '700 pixels work area plus border this assumes no menu

UpperLeftX = int((DisplayWidth-WindowWidth)/2) '>>>>>> this IS used
UpperLeftY = int((DisplayHeight-WindowHeight)/2)'>>>>>>> this IS used

'+++ Not used for now, useful later +++++++++++++++++++++++++++++++++
midx=int(WindowWidth/2)
midy=int(WindowHeight/2)
'++++++++++++++++++++++++++++++++++++++++++++++++++++++

'========== revisit later to get working button =====================================

10 button #mywindow1, "Clear", [clearScreen], LR, 50, 10  '<<<<<<<<<<<    made clear a SUB called clearScreen but that didn't work either
'$$$$Not neede for now, $$$$$ jumps or calls label Clear, cleans any previous screen, WHAT is LR, 50, 10
'BUTTON #handle.ext, "label", returnVar, corner, x, y {, width, height}
'====================================================================================


open "Just my header name Fractzals002" for graphics_nsb as #mywindow1
#mywindow1 "trapclose [quit]"   'this sends the prgm to exit on window closing


'                             SETUP FOR KEYPRESSES
#mywindow1 "when characterInput charIn"  '<<<<<<<<<<<<<<< This sets up for keyboard input
#mywindow1 "setfocus"  ' <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<  need this too for keypresses to go to window

#mywindow1 "down; fill black"  'down only needs to done once for drawing unless doing turtle drawing



call draw
wait

[clearScreen]
20 #mywindow1 "down ; fill black"
' fill black is like cls screen with a color
30 'print #mywindow1.txtEdit, " 5 sec delay now"
  call pause 2000 '5 sec delay is awlful long here is 2 sec
wait

[quit]
close #mywindow1
end



sub draw
'calculate and draw the points
   scan   'check for kb inputs ??? kb interrupt ???'
  for j= 1 to 700
   xp=j
   yp=j
    #mywindow1 "color "; "red"
    #mywindow1 "set ";xp;" ";yp
  next j
   'NOW DO A GREEN (or other color) line
  for j= 1 to 700
       xp=j  'add offset for multiple draws
       yp=700-j
       #mywindow1 "color "; "green"
       #mywindow1 "set ";xp;" ";yp
  next j
   'Now draw horz line across top
   'NOW DO A Blue (or other color) line
   for y= 1 to 700 step 10
       xp=j 'add offset for multiple draws, later
       #mywindow1 "color "; "yellow"
       #mywindow1 "line ";0;" ";y;" ";700;" ";y
   next y
'random points now, as new lines are drawn, the old lines will begin to fad as
' random seq writes over them point by point
 for a = 1 to 1000  'lots of points of lights or we will never see them, they are tiny !
   xp= int(rnd(1)*700) '+ 1
   yp= int(rnd(1)*700) '+ 1
   #mywindow1 "color "; "blue"
   #mywindow1 "set ";xp;" ";yp
 next a
end sub

sub charIn H$, c$  ' H$ is window handle dont worry about it for 1 window c$ is charcter$ keypress
   if asc(c$) = 32 then ' if spacebar
      #H$ " fill black"
   else
       if asc(c$) = 13 then 'enter keypress
          call draw
       else
           if c$ = "Q" or c$ = "q" then
               close #mywindow1
               end
           else
           'ect....
           end if
       end if
   end if
end sub

sub pause mil   'tsh version has scan built-in
   t0 = time$("ms")
   while time$("ms") < t0 + mil : scan : wend
end sub


Also I notice when I skip clear button and just do spacebar, enter, spacebar, enter... some kind of ghost screen or error message is appearing just before draw redraws the picture.

[Rod]

Well its one of the reasons I don't like these timer loops. When you are in the timer sub you issue a SCAN statement. That looks for other events like button presses and hauls you out of the sub looking for [clearscreen] which is a branch label in the main program and does not exist in the sub. So it can't be found.

[B+]

Jul 26, 2020 20:02:18 GMT Rod said:

Well its one of the reasons I don't like these timer loops. When you are in the timer sub you issue a SCAN statement. That looks for other events like button presses and hauls you out of the sub looking for [clearscreen] which is a branch label in the main program and does not exist in the sub. So it can't be found.

Thanks now I get it.

OK so I comment out the CALL pause (which I didn't like either) THEN I click the Clear button, clears but the <Enter> button to call draw won't work.


Oh I know, setfocus!

[clearScreen]
20 #mywindow1 "down ; fill black"
' fill black is like cls screen with a color
30 'print #mywindow1.txtEdit, " 5 sec delay now"
  'call pause 2000 '5 sec delay is awlful long here is 2 sec
  #mywindow1 "setfocus"
wait


fixed!

Any idea what that yellow box artifact is just before draw is finished redrawing (after you hit <enter> there is a yellow box flash in screen before the draw drawing appears).

[Rod]

The artifact you see is a Windows thing. Its there because Just BASIC has no way to sync with the screen refresh. So the screen gets refreshed part way through our drawing, that's the artifact, then the screen refreshes again by then the whole drawing has been completed. Windows is in charge of when a window gets repainted and its a bit random, not even 60Hz.

In LB5 Carl is giving us a behind the screen buffer and a mechanism to force a screen redraw. That will make a big difference because part drawn graphics will never appear, you will only ever see the finished graphic. So no more flashing and flickering just rock steady graphics.

[Rod]

When graphics drawing there are a few things to think about. Drawing uses memory, you need to manage that memory use and you can also make it work in your favour.

Here I use down just once and fill black just once. Then I repeatedly clear old drawing memory use with discard and then reuse the previous segment named "bac" to redraw the background. It could be a much more complex background.

#mywindow1 "down; fill black ; flush bac"  'down only once, fill black , save as segment "bac"

#mywindow1 "discard ; redraw bac" 'dump old drawing from memory, redraw the black background, all instead of fill black again


[Rod]

Here is my take on how to write the program using all subs.


nomainwin
'our window needs to be bigger than the pixels we want to see
'windows needs room for the title bar and the frame
WindowWidth = 700+8
WindowHeight = 700+32
'center the window
UpperLeftX = int((DisplayWidth-WindowWidth)/2)
UpperLeftY = int((DisplayHeight-WindowHeight)/2)
button #1, "Clear", clearScreen, LR, 50, 10
'open a graphic window with no scroll bars or resizing frame
open "Just Demo" for graphics_nsb_nf as #1

'either use all [branchlabel] or all Subs, less mixups that way
#1 "trapclose quit"
'start event trapping for keypresses
#1 "when characterInput charIn"
'down only once, fill black only once , save as segment "bac"
#1 "down; fill black ; flush bac"

call draw
wait

sub clearScreen h$
   'this event handler is passed the handle of the screen
   'we use it by prepending #
   #h$ "discard ; redraw bac"
   #h$ "setfocus"
   'button press takes focus away from screen so set focus back to screen
end sub

sub quit h$

   'this event handler is passed the handle of the screen
   'we actually use it by prepending #
   close #h$
   end
end sub



sub draw
   'calculate and draw the points
   #1 "color red ; line 0 0 699 699"
   #1 "color green ; line 699 0 0 699"
   #1 "color yellow" 'set once
   for y= 0 to 699 step 10
       #1 "line 0 ";y;" 699 ";y
   next
   #1 "color blue" 'set once
   for a = 1 to 10000
       #1 "set ";rnd(0)*700;" ";int(rnd(0)*700/10)*10
   next
end sub

sub charIn h$, c$
   'this event handler is passed the handle of the screen and the key pressed
   'here we just pass the handle on, we dont actually use it
   select case
       case c$ = chr$(32)
           call clearScreen h$ 'spacebar
       case c$ = chr$(13)
           call clearScreen h$ ' enter
           call draw
       case c$ = "Q" or c$ = "q"
           call quit h$
       end select
end sub







[B+]

Thanks Rod that was helpful for me specially about flush and discard.

[honkytonk]

If you click on the closing cross while the program is in a sub-pause, this generates an error; that doesn't happen with a gosub [pause]