flip and mirror

[tsh73]

LB has bitBlt API and stuff, JB can creatively use getbmp/drawbmp.
Might as well get handy.
("flip" and "mirror" do what they say,
"copy" just getbmp/drawbmp to another place,
and "rect" could be used for debugging - to pinpoint exact place we copy from.)
'mirror and flip
'by getbmp line by line
'and ouputting backwards
nomainwin
open "test" for graphics_nsb_nf as #gr
#gr "trapclose [quit]"
#gr "down"
'#gr "fill white; flush"
#gr "home; posxy cx cy"

#gr "home"
#gr "backcolor yellow; circlefilled 50"

#gr "backcolor white; circle 20"
call rect "#gr", cx, cy, 30, 20,
call copy "#gr", cx, cy, 30, 20, 80,100

call mirror "#gr", cx, cy, 30, 20, 200,100
call flip "#gr", cx, cy, 30, 20, 200,200

#gr "flush"

wait

[quit]
   timer 0
   close #gr
end

sub rect gr$, x,y,w,h
   #gr$ "place " ;x;" ";y
   #gr$ "box ";x+w;" ";y+h
end sub

sub copy gr$, x,y,w,h,destX,destY
   #gr$ "getbmp tmpBmp ";x;" ";y;" ";w;" ";h
   #gr$ "drawbmp tmpBmp ";destX;" ";destY
end sub

sub mirror gr$, x,y,w,h,destX,destY
   for i=1 to w
       #gr$ "getbmp tmpBmp ";x+w-i;" ";y;" 1 ";h
       #gr$ "drawbmp tmpBmp ";destX+i;" ";destY
   next
end sub

sub flip gr$, x,y,w,h,destX,destY
   for i=1 to h
       #gr$ "getbmp tmpBmp ";x;" ";y+h-i;" ";w;" 1 "
       #gr$ "drawbmp tmpBmp ";destX;" ";destY+i
   next
end sub



[B+]

Nice, thanks!

[B+]

Let's add Rotations to our bag of tricks!

' Mirror, Flip and Rotation.txt for JB v2 B+ 2019-02-04
' B+ mod adding to tsh73 tips and utilties: mirror and flip by getbmp line by line and ouputting backwards
' 2019-02-04 B+ adding rotation and demos


global pi, d2r, r2d, XMAX, YMAX

pi = acs(-1)
d2r = pi/180 'convert degree angle units to radians
r2d = 180/pi 'convert radian angle units to degrees
XMAX = 500 '<======================================== actual drawing space needed
YMAX = 600 '<======================================== actual drawing space needed

nomainwin
WindowWidth = XMAX + 8
WindowHeight = YMAX + 32
UpperLeftX = (DisplayWidth - XMAX) / 2  'or delete if XMAX is 1200 or above
UpperLeftY = (DisplayHeight - YMAX) / 2   'or delete if YMAX is 700 or above

open "Mirror, Flip and Rotation" for graphics_nsb_nf as #gr
#gr "trapclose quit"
#gr "when characterInput charIn"
#gr "setfocus"
#gr "font arial ";7;" ";16
#gr "down"
#gr "home; posxy cx cy"

'draw sample graphic
#gr "backcolor yellow; circlefilled 50"
#gr "backcolor white; circle 20"
call rect "#gr", cx, cy, 30, 20

'draw a copy
call copy "#gr", cx, cy, 30, 20, cx + 70 ,cy
#gr "place ";cx + 70 + 30 + 10;" ";cy + 15;";|";"Copy"

'draw a mirror
call mirror "#gr", cx, cy, 30, 20, cx - 70 - 30, cy
#gr "place ";cx - 70 - 30 - 10 - 40;" ";cy + 15;";|";"Mirror"

'draw a flip
call flip "#gr", cx, cy, 30, 20, cx - 15, cy - 70 - 20
#gr "place ";cx - 15 + 2;" ";cy - 70 - 25 ;";|";"Flip"

'draw 11 rotations
#gr "backcolor white"
for i = 1 to 11
   scan
   rada = rada + 2*pi/12
   call rotate "#gr", cx, cy, 30, 20, cx - 15, cy + 70, rada
   #gr "color black"
   #gr "place ";cx - 35;" ";cy + 70 + 20 + 5 + 20;";|";str$(int(rada * r2d + .01));" degrees"
   #gr "place ";cx - 25;" ";cy + 70 + 20 + 5 + 40;";|";"Rotation"
   call pause 1500
   if i < 11 then
       #gr "color white"
       #gr "place ";cx;" ";cy + 70 + 10
       #gr "circlefilled 19"
   end if
next

'now that we can rotate a bmp, try rotating letters
'drawing letters for bmp copies, doing in a column to get clear picture of each letters
for l = 1 to 26
   #gr "place ";0;" ";20 * l;";|";mid$("ABCDEFGHIJKLMNOPQRSTUVWXYZ", l, 1)
next

'testing char cell dimensions by drawing boxes around letters,
'call rect "gr#", 26*8.5, 0, 9, 20
'find cw, ch dang! cw way too inconsistent, so draw the letters in a column instead of a row
cw = 12: ch = 20 'character cell width and height

'drawing circle of letters
lradius = 180  'letters radius
la = 2 * pi/26 'angle between letters
for l = 0 to 25 '26 letters
   ' the letter A is North at letter 0 so add 270 degrees = 3*pi/2 to adjust upright letter at North
   call rotate "#gr", 0, (l)*20, cw, ch, cx + lradius * cos(la * l + 3*pi/2 ), cy + lradius * sin(la * l + 3*pi/2), la*l
next

#gr "flush"
wait

sub rect gr$, x,y,w,h
   #gr$ "place " ;x;" ";y
   #gr$ "box ";x+w;" ";y+h
end sub

sub copy gr$, x,y,w,h,destX,destY
   #gr$ "getbmp tmpBmp ";x;" ";y;" ";w;" ";h
   #gr$ "drawbmp tmpBmp ";destX;" ";destY
end sub

sub mirror gr$, x,y,w,h,destX,destY
   for i=1 to w
       #gr$ "getbmp tmpBmp ";x+w-i;" ";y;" 1 ";h
       #gr$ "drawbmp tmpBmp ";destX+i;" ";destY
   next
end sub

sub flip gr$, x,y,w,h,destX,destY
   for i=1 to h
       #gr$ "getbmp tmpBmp ";x;" ";y+h-i;" ";w;" 1 "
       #gr$ "drawbmp tmpBmp ";destX;" ";destY+i
   next
end sub

' this uses Atan2, angleAndDistance, globals pi, r2d, d2r
sub rotate gr$, x, y, w, h, destX, destY, rotateRadians
   x0 = x + w/2 : y0 = y + h/2
   rx0 = destX + w/2 : ry0 = destY + h/2
   for ry = y to y + h
       for rx = x to x + w
           call angleAndDistance x0, y0, rx, ry, ra, dist
           #gr$ "getbmp tmpBmp ";rx;" ";ry;" ";1.5;" 1.5"
           #gr$ "drawbmp tmpBmp ";rx0 + dist * cos(ra + rotateRadians);" ";ry0 + dist * sin(ra + rotateRadians)
       next
   next
end sub

'this sub needs Atan2(y, x) Function and r2d gobal constant to convert radians to degrees
sub angleAndDistance x1, y1, x2, y2, byref angle, byref distance
   angle = Atan2(y2 - y1, x2 - x1)
   distance = sqr((x2 - x1)^2 + (y2 - y1)^2)
end sub

' this sub needs global constants pi and d2r for converting degrees to radians
Function Atan2(y, x)
   'Atan2 is a function which determines the angle between points
   'x1, y1 and x2, y2. The angle returned is in radians
   'The angle returned is always in the range of
   '-PI to PI radians (-180 to 180 degrees)
   '==============================================================
   'NOTE the position of Y and X arguments
   'This keeps Atan2 function same as other language versions
   '==============================================================

  If x = 0 Then
      If y < 0 Then
           Atan2 = -1.5707963267948967
       Else
           Atan2 = 1.5707963267948967
       End If
  Else
      chk = atn(y/x)
      If x < 0 Then
          If y < 0 Then
               chk = chk - 3.1415926535897932
           Else
               chk = chk + 3.1415926535897932
           End If
      End If
       Atan2 = chk
  End If
  'thanks Andy Amaya

  'normalize angle between 0 and 2*pi
  'if Atan2 < 0 then Atan2 = Atan2 + 2 * pi
End Function

sub stext x, y, message$ 'note: have to reset fore or back color after ink
   #gr "place ";x;" ";y;";|";message$
end sub

sub charIn H$, c$
   call quit H$
end sub

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

sub quit H$
   timer 0
   close #H$
   end
end sub


[tsh73]

Surprising.
Now I wonder if it is faster then with getPixel.

And if picture can be made any smoother by using colors from nearby points.

[B+]

Alas, we still don't know any color values, just copy paste a pixel at one place to a pixel at another. The coverage is poor except for angles that round well. Still pretty dang clever, for amusement.

A thought:
If we could get a list of every point in the destination area, we could back track and find a corresponding point in the source area and send that bmp over to that destination point, then the entire destination area would get covered with something.

[tenochtitlanuk]

That's pretty well exactly what I did for my LB programs for warping images, making images only understandable viewed in a reflecting cylindrical mirror, etc.
Conical projectionlink
Image effects on Lena image

[Enzo]

Can sprites be rotated?

[Rod]

Yes by 180o, if you want other angles you need to rotate the drawn sprite and capture all angles you need as sprite images. Then load all those images to one sprite and use the spritimage command to show the angle you need at any time. There are one or two rotation drawing examples to search out on this and the Liberty BASIC forum.

[tsh73]

Can sprites be rotated?

90degrees
justbasiccom.proboards.com/thread/609/rotate-sprite

[Rod]

Any angle you like. So too Sprite Creator.

libertybasiccom.proboards.com/thread/383/sprite-rotation