BAM: Thinking about adding a SCROLL statement

[CharlieJV]

   

[Petr]

That's an interesting idea. In the case of such a command with QB64, I would suggest two more parameters at the end: Source and target screen. This can be done very easily with _PutImage.

Something as this, maybe:

Code: (Select All)

image& = _NewImage(400, 400, 256)

_Dest image&

Cls , 140

_PrintString (200 - 64, 200 - 8), "12345678"

_Dest 0



Screen _NewImage(1024, 768, 32)

Do

    k& = _KeyHit

    Select Case k&

        Case 18432: Yp = Yp + 10

        Case 20480: Yp = Yp - 10

        Case 19200: Xp = Xp + 10

        Case 19712: Xp = Xp - 10

    End Select

    Line (311, 153)-(713, 555), _RGB32(255), BF

    SCROLL 312, 154, 712, 554, Xp, Yp, image&, _Dest

    _Display

    _KeyClear

    _Limit 20

Loop



Sub SCROLL (x1%, y1%, x2%, y2%, h%, v%, s&, d&)

    Wi% = _Width(s&)

    He% = _Height(s&)

    _PutImage (x1%, y1%)-(x2%, y2%), s&, d&, (h%, v%)

End Sub

[bplus]

Yeah Charlie does have interesting ideas!

I seem to recall some scrolling project from way back, maybe with Petr?

I think it could be done with a virtual screen array so _PutImage could be worked around easily.

[Petr]

Hi BPlus,

Hi BPlus, I really don't know. It's possible, I've done more. But working with _PutImage is, think, the most suitable for this, because an image is inserted (so it can also be the output screen of a subprogram) and thus it can be linked with input from the keyboard and mouse, it doesn't have to be limited only to display, but it can work together with the user.

[bplus]

Hey @Petr, remember this is for BAM and I don't think it has _PutImage capability?

If any _Keywords are used from QB64 era I think Charlie would have had to put them in himself.

[Petr]

You're right, BPlus. Unfortunately I don't know the list of valid BAM commands, although I found the BAM IDE online, it looks really nice.

[CharlieJV]

You're right, BPlus. Unfortunately I don't know the list of valid BAM commands, although I found the BAM IDE online, it looks really nice.

You'll find links to keywords (and many things BAM, work in progress) here.

Thanks for the kind words !

[Petr]

@CharlieJV 

Thanks for the link. Since BAM supports GET and PUT for graphics, I assume that's the way to go for the SCROLL statement. So if it is about scrolling images. But if the text from the text field should be scrolled, then in that case I don't know how I would go about it. I'm looking at the help for BAM. Is Declare Sub mandatory? Is virtual screens supported?

[CharlieJV]

@CharlieJV 

Thanks for the link. Since BAM supports GET and PUT for graphics, I assume that's the way to go for the SCROLL statement. So if it is about scrolling images. But if the text from the text field should be scrolled, then in that case I don't know how I would go about it. I'm looking at the help for BAM. Is Declare Sub mandatory? Is virtual screens supported?

Every pixel on the screen is, behind the scenes, stored in a javascript array.

Scroll just juggles the content of that array around.  (I think I'll be adding a "wrap%" argument to the statement.)

Yeah, BAM needs a subroutine/function defined before any reference to it;  so either the definition at the top or the declare sub/function statement at the top.

Currently no virtual screens (or pages) are supported.  Just the one screen (for the moment, as I let thoughts fester in the back of my sponge.)

[CharlieJV]

The Three Little Pigs test for vertical scroll:

Up

• Run the program
  
• View the source code
  

Down

• Run the program
  
• View the source code