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Forum Index : Microcontroller and PC projects : CMM2 - et al - Can BOX w or h be -ve?
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| Andrew_G Guru  Joined: 18/10/2016 Location: AustraliaPosts: 840 |
Morning all, Is it me or can the w or h in a BOX command NOT be negative? Mathematically it is possible but MMBasic does nothing (ie no box and no error). Is it easy to fix or should I find a work around? (I'm not sure if it is only CMM2's version of MMBasic) Cheers, Andrew |
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| berighteous Senior Member  Joined: 18/07/2020 Location: United StatesPosts: 110 |
The workaround is don't put negative numbers in w or h. Why are you putting negative numbers in box? |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 840 |
Thanks, I'm not putting -ve numbers in a box - the equations are! It might help you to know that LINE accepts -ve numbers - try: LINE 400, 200, -200, 100 A -ve number merely instructs BASIC to go up or left, in this case, on a bar graph. I'm porting a 2,500 line QB45 program to CMM2 and because QB45 accepts and correctly interprets, -ve numbers I've noticed that MMBasic appears not to. I then delved further. Sure I can re-write the equations or test for -ve but I simply, and I think quite reasonably, inquired if it was intended. Andrew |
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| capsikin Guru Joined: 30/06/2020 Location: AustraliaPosts: 341 |
The old colour maximite 1 manual (Ver 4.5) doesn't have a box command, and the box version of the line command takes two opposite corners so it doesn't take a width and height. |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 840 |
Hi Capsikin, By this: I was thinking more of whether the MM170, MM+ etc had the same "feature" (because I haven't tested it on them) rather than the CMM1. It is easy (but a little time consuming - and I am part way through) to fix my current program but I thought it worth asking if it was intended. Cheers, Andrew |
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| mclout999 Guru Joined: 05/07/2020 Location: United StatesPosts: 430 |
I have not liked this form of the box and rbox command because it is atypical of traditional basics like GW and most of the others I have used. Are there other basics that used this form. It forces more complex computations that the old x-y x-y format of the basics I am accustomed to. If the old MMbasic had the traditionl form why was this new form chosen? I mean by this is there a benefit of this form. I find it more cumbersome and am sure it will make conversion of old GW and old MMbasic programs more difficult or am I wrong? |
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| capsikin Guru Joined: 30/06/2020 Location: AustraliaPosts: 341 |
For drawing a small fixed size box to erase a sprite or tile I find the new form easier. For drawing over most of the screen I think it would be harder. I haven't used rbox. I like the name box better than line for drawing a rectangle. I did find it made porting invaders more difficult, if I was starting again I'd write a box_corners sub that takes more of the old arguments. |
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vegipete Guru Joined: 29/01/2013 Location: CanadaPosts: 1082 |
A variation that expects coordinates of two (opposite) corners: boxy 200,200,50,-50,3,rgb(white),rgb(magenta) ' Subroutine to draw a box given coordinates of opposite corners ' Any number of coordinates can be negative ' Lineweight (lw), colour (c) and fill colour (cfill) must be given if other than 0 sub boxy(x1,y1,x2,y2,lw,c,cfill) local float xs,ys,w,h h = abs(x1 - x2) v = abs(y1 - y2) xs = min(x1,x2) ys = min(y1,y2) box xs,ys,h,v,lw,c,cfill end sub The only problem is default colours are not obeyed. If you skip a parameter, it will be filled in with the value 0. A simple variation of this could be made to accept h and v with possible negative signs. Visit Vegipete's *Mite Library for cool programs. |
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| capsikin Guru Joined: 30/06/2020 Location: AustraliaPosts: 341 |
Ah okay. I would guess it is intended, because in the CMM2 manual it says for box "with the top left hand corner at 'x' and 'y'". Although for rbox it says "starting at 'x' and 'y'" instead. That's just my guess though. |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 840 |
Thanks Pete, That will work! (But I'm still interested as to whether this is a "feature", "quirk" or "bug"). Cheers, Andrew |
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| capsikin Guru Joined: 30/06/2020 Location: AustraliaPosts: 341 |
This draws a width and height zero box if x1=x2 and y1=y2, possibly it should be width and height 1. (hmm, I'm assuming x1 and x2 etc are pixel coordinates. I don't see it specified if the CMM1 box coordinates are for the corner pixels themselves, or the corner of the corner pixels, so I could be wrong.) (edited to add: thanks, that will be helpful) Edited 2020-08-15 18:21 by capsikin |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8578 |
The CMM2 works exactly like the Micromite (same code) and ignores the BOX and RBOX commands if w or h are negative or zero HOWEVER, if you ask really nicely then I might just remove the restriction in the next beta  |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 840 |
Hi Peter, Your call (I've worked around my initial issue) but it did seem strange . . . (How nice do I have to be? - but I DO have my limits). Thanks for all your good work and cheers,  Andrew |
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