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Active Forums => Programs => Topic started by: TempodiBasic on June 21, 2020, 06:28:36 am

Title: a little demo about VIEW WINDOW and PMAP: beginners info
Post by: TempodiBasic on June 21, 2020, 06:28:36 am
Hi guys
seeing that it is in the air to talk about managing of physical screen of pc and how to change its dimensions and cohordinate's system and moreover how to fragment it into more little areas that are indipendent among them for dimensions, cohordinate's system
I post here my little contibution
a demonstration lesson about VIEW WINDOW and PMAP using also _PRINTSTRING and _MOUSEcohordinates as Bplus has stressed that are out of this system and must be adapted to interact properly with it.

Code: QB64: [Select]
  1. SCREEN _NEWIMAGE(800, 600, 32)
  2.  
  3.  
  4. ' 0-799<--->    0-599 ^
  5. '                     |
  6. '                     v
  7.  
  9. _TITLE "Window View and PMAP: some info"
  11.  
  12. COLOR _RGB32(0, 10, 255)
  13.  
  14. LINE (-2, -2)-(802, 602), _RGB32(255, 0, 0), B
  15. _PRINTSTRING (10, 10), "Remember you can make graphic out of screen!"
  18. WINDOW (-10, -10)-(810, 610)
  19. LINE (-2, -2)-(802, 602), _RGB32(255, 0, 0), B
  20. _PRINTSTRING (10, 10), "Remember you can make graphic out of screen!"
  23. _PRINTSTRING (10, 10), "You cannot set an area of screen not visible (out of screen visible) by VIEW!"
  24. _PRINTSTRING (10, 40), " you'll get an error messagebox, please choose to continue"
  25. VIEW (-2, -2)-(802, 602), _RGB32(200, 20, 20), _RGB32(0, 0, 255)
  27.  
  28. VIEW (1, 1)-(798, 598), _RGB32(127, 127, 127), _RGB32(200, 10, 250)
  29. _PRINTSTRING (10, 10), "You can choose the whole screen with coordinates or only VIEW with no parameters"
  32. WINDOW SCREEN(1, -10)-(850, 400) ' used SCREEN to maintain the y = 0 at top and y = max at bottom
  33. LINE (-2, -2)-(802, 602), _RGB32(200, 20, 20), B
  34. _PRINTSTRING (10, 10), "Each graphic instruction follow the dimensions of WINDOW instruction"
  36. _PRINTSTRING (10, 30), " the exceptions are _PRINTSTRING and _MOUSEpositions. "
  37. _PRINTSTRING (10, 60), "In fact this text and line are in different positions"
  38. LINE (10, 30)-(140, 30), _RGB32(255, 120, 10)
  40. _PRINTSTRING (10, 90), "Move mouse in the next demo"
  43. WINDOW (1, -10)-(850, 400)
  44. a% = 10: b% = 40: c% = b% + 20
  47.         WHILE _MOUSEINPUT: WEND
  48.         mx% = _MOUSEX
  49.         my% = _MOUSEY
  50.         LMB% = _MOUSEBUTTON(1)
  51.         RMB% = _MOUSEBUTTON(2)
  52.         CLS
  53.         _PRINTSTRING (10, 20), "X = " + STR$(mx%) + "  Y= " + STR$(my%)
  54.         _PRINTSTRING (160, 20), " Move mouse to TopLeft and BottomRight corner of screen and see its value"
  55.  
  56.         _PRINTSTRING (a%, b%), "press Right Mouse Button to move this text on the screen to mouse's position"
  57.         _PRINTSTRING (a%, c%), "press Left Mouse Button to quit this demonstration"
  58.         _PRINTSTRING (a%, c% + 40), " Lines and text aren't on the same position!"
  59.         LINE (a%, b%)-(a% + 100, b%), _RGB32(10, 200, 10)
  60.         LINE (a%, c%)-(a% + 100, c%), _RGB32(10, 200, 10)
  61.         IF RMB% THEN
  62.             a% = mx%
  63.             b% = my%
  64.             c% = my% + 20
  65.         END IF
  66.         _DISPLAY
  67.     END IF
  74. COLOR _RGB32(255, 0, 0)
  75. _PRINTSTRING (20, 10), "In sum: VIEW selects an area of the screen visible. WINDOW defines custom dimensions of that area"
  76. _PRINTSTRING (20, 30), "WINDOW inverts Y-axis, SCREEN parameter restores the original direction of Y-axis"
  78. VIEW (100, 100)-(500, 200), _RGB32(127, 127, 127)
  79. WINDOW SCREEN(1, 1)-(100, 100)
  80. LINE (50, 50)-(150, 50), _RGB32(127, 1, 127)
  81.  
  82. VIEW (100, 300)-(500, 400), _RGB32(127, 127, 127)
  83. WINDOW SCREEN(1, 1)-(200, 100)
  84. LINE (50, 50)-(150, 50), _RGB32(127, 1, 127)
  85.  
  86. VIEW (100, 500)-(500, 598), _RGB32(127, 127, 127)
  87. WINDOW SCREEN(-100, 100)-(100, 1) ' the WINDOW statement has an inner sorting of dimensions
  88. LINE (50, 50)-(150, 50), _RGB32(127, 1, 127)
  93. _PRINTSTRING (10, 10), " Now draw by mouse in the upper rectangle by left click, quit by Right click"
  94. VIEW (100, 100)-(500, 200), , _RGB32(127, 127, 0)
  95. WINDOW SCREEN(1, 1)-(300, 300)
  96. LINE (50, 50)-(150, 50), _RGB32(127, 1, 127)
  97.  
  98. VIEW (100, 300)-(500, 400), , _RGB32(127, 127, 0)
  99. WINDOW SCREEN(1, 1)-(200, 100)
  100. LINE (50, 50)-(150, 50), _RGB32(127, 1, 127)
  103.  
  105.     mx% = _MOUSEX
  106.     my% = _MOUSEY
  107.     LMB% = _MOUSEBUTTON(1)
  108.     RMB% = _MOUSEBUTTON(2)
  109.     IF LMB% THEN
  110.         IF mx% > 99 AND mx% < 501 THEN
  111.             IF my% > 99 AND my% < 201 THEN
  112.                 ' it draws in the first viewport
  113.                 VIEW (100, 100)-(500, 200), , _RGB32(127, 127, 0)
  114.                 WINDOW SCREEN(1, 1)-(300, 300)
  115.                 LINE (50, 50)-(150, 50), _RGB32(127, 1, 127)
  116.  
  117.  
  118.                 LINE -STEP(INT(PMAP(mx%, 2)), INT(PMAP(my%, 3))), _RGB32(200, 100, 200, 255)
  119.                 _DISPLAY
  120.                 VIEW
  121.                 COLOR _RGB32(200, 200, 0)
  122.                 _PRINTSTRING (100, 250), STR$(mx%) + " -> " + STR$(INT(PMAP(mx%, 2))) + "  " + STR$(my%) + " --> " + STR$(INT(PMAP(my%, 3)))
  123.  
  124.                 ' it draws in the second viewport
  125.                 VIEW (100, 300)-(500, 400), , _RGB32(127, 127, 0)
  126.                 WINDOW SCREEN(1, 1)-(200, 100)
  127.                 LINE (50, 50)-(150, 50), _RGB32(127, 1, 127)
  128.  
  129.  
  130.                 LINE -STEP(INT(PMAP(mx%, 2)), INT(PMAP(my%, 3))), _RGB32(255, 255, 255, 255)
  131.                 _DISPLAY
  132.                 VIEW
  133.                 COLOR _RGB32(255)
  134.                 _PRINTSTRING (100, 450), STR$(mx%) + " -> " + STR$(INT(PMAP(mx%, 2))) + "  " + STR$(my%) + " --> " + STR$(INT(PMAP(my%, 3)))
  135.                 _DISPLAY
  136.             END IF
  137.         END IF
  138.     END IF
  139.  
  140. LOOP UNTIL RMB%
  145. _PRINTSTRING (10, 10), "Thanks to watching"
Thanks to read
Title: Re: a little demo about VIEW WINDOW and PMAP: beginners info
Post by: OldMoses on June 21, 2020, 09:00:41 am
Nice presentation. Some of the sleep statements could be a little longer for us slow readers. ;)

I've found WINDOW to be a good way to predetermine how my graphics interacts with the data generated. I use it quite a lot, particularly for quickie applications. There is a tradeoff, I can define my space in R3 like I'm used to, but then I have to be aware to alter how any trig functions behave. It can be a bit of a pain working between vector and polar coordinates. This was how I handled the space flight program I've been endlessly working on. Generate a sub-image with custom coordinates using VIEW & WINDOW then _PUTIMAGE to the mainscreen.

One painful lesson I learned from that approach, if your "model space" is much larger than your "display space" and contains a lot of "off-screen" details, you're well served to use logical operators that avoid the processing time of drawing things that will not actually be displayed. Otherwise, things can slow to a crawl if the graphics are complex, such as liberal use of Steve's fcirc, in my case.

I'm going to have to get familiar with PMAP, it suddenly occurred to me that it might hold the key to doing some mouse selection bugs I've been dealing with.

Title: Re: a little demo about VIEW WINDOW and PMAP: beginners info
Post by: TempodiBasic on June 22, 2020, 07:18:05 pm
Thanks OldMoses
I'll adjust a bit those SLEEPs

I have little experience with WINDOW and PMAP  while a bit more with VIEW but I find their use very useful in some kind of graphic work.

I found an example of Mandelbrot fractal in Qbasic with use of WINDOW VIEW and PMAP. It was ok but I have thought to make it a bit more adaptable so I convert the program into a SUB and I play to draw Mandelbrot Fractal in 3 different viewport just to show how can be useful such instructions.
Thanks to read and to try following code.

Code: QB64: [Select]
  1. ' a little demonstration about WINDOW, VIEW and PMAP
  2. SCREEN _NEWIMAGE(800, 600, 8)
  4. _TITLE "a little demonstration about WINDOW, VIEW and PMAP"
  6.  
  7. 'This example uses the VIEW and WINDOW statements to define a graphics
  8. 'viewport and window. The PMAP function is used to convert viewport
  9. 'coordinates to window coordinates.  The program generates a fractal
  10. 'that shows a subset of the complex numbers called the "Mandelbrot Set."
  11.  
  12. DEFINT A-Z 'Default variable type is integer.
  13.  
  14. 'Set maximum number of iterations per point.
  15. CONST MAXLOOP = 30, MAXSIZE = 1000000
  16. CONST FALSE = 0, TRUE = NOT FALSE 'Boolean constants.
  17.  
  18. ' set maximum viewport parameters (whole screen)
  19. CONST VLm = 0, VUm = 0, VRm = 799, VBm = 599
  20. ' set  first viewport  parameters
  21. CONST VL1 = 50, VU1 = 50, VR1 = 200, VB1 = 500
  22.  
  23. ' set  second viewport  parameters
  24. CONST VL2 = 300, VU2 = 300, VR2 = 700, VB2 = 500
  25.  
  26. 'Set window paramters.
  27. CONST WLeft = -1000, WRight = 250, WTop = 625, WBottom = -625
  28.  
  29. ' declaration global variables
  30. DIM SHARED ColorRange AS INTEGER
  31.  
  32. ColorRange = 15
  33.  
  34. 'Define viewport and corresponding window
  35. ' the whole window
  36. VIEW (VLm, VUm)-(VRm, VBm), 0, ColorRange
  37. WINDOW (WLeft, WTop)-(WRight, WBottom)
  38. DrawMandelbrot VLm, VRm, VBm, VUm
  39.  
  40. ' a vertical little window
  41. VIEW (VL1, VU1)-(VR1, VB1), 0, ColorRange
  42. WINDOW (WLeft, WTop)-(WRight, WBottom)
  43. DrawMandelbrot VL1, VR1, VB1, VU1
  44.  
  45. ' an horizhontal window
  46. VIEW (VL2, VU2)-(VR2, VB2), 0, ColorRange
  47. WINDOW (WLeft, WTop)-(WRight, WBottom)
  48. DrawMandelbrot VL2, VR2, VB2, VU2
  49.  
  50. LOCATE 1, 10: PRINT "Press any key to quit.";
  52.  
  53. SUB DrawMandelbrot (Left AS INTEGER, Right AS INTEGER, Bottom AS INTEGER, Up AS INTEGER)
  54.  
  55.     DIM Xlength AS INTEGER, Ylength AS INTEGER, Y AS INTEGER, X AS INTEGER
  56.     DIM ColorWidth AS INTEGER, LogicY AS INTEGER, LogicX AS INTEGER
  57.     DIM OldColor AS INTEGER, PColor AS INTEGER, RealNum&, ImagNum&
  58.     DIM MandelX&, MandelY&
  59.  
  60.     Xlength = Right - Left
  61.     Ylength = Bottom - Up
  62.     ColorWidth = MAXLOOP \ ColorRange
  63.  
  64.     'Loop through each pixel in viewport and calculate whether or not
  65.     'it is in the Mandelbrot Set.
  66.     FOR Y = 0 TO Ylength 'Loop through every line in the viewport.
  67.         LogicY = PMAP(Y, 3) 'Get the pixel's logical y coordinate.
  68.         PSET (WLeft, LogicY) 'Plot leftmost pixel in the line.
  69.         OldColor = 0 'Start with background color.
  70.  
  71.         FOR X = 0 TO Xlength 'Loop through every pixel in the line.
  72.             LogicX = PMAP(X, 2) 'Get the pixel's logical x coordinate.
  73.             MandelX& = LogicX
  74.             MandelY& = LogicY
  75.  
  76.             'Do the calculations to see if this point is in the Mandelbrot Set.
  77.             FOR I = 1 TO MAXLOOP
  78.                 RealNum& = MandelX& * MandelX&
  79.                 ImagNum& = MandelY& * MandelY&
  80.                 IF (RealNum& + ImagNum&) >= MAXSIZE THEN EXIT FOR
  81.                 MandelY& = (MandelX& * MandelY&) \ 250 + LogicY
  82.                 MandelX& = (RealNum& - ImagNum&) \ 500 + LogicX
  83.             NEXT I
  84.  
  85.             'Assign a color to the point.
  86.             PColor = I \ ColorWidth
  87.  
  88.             'If color has changed, draw a line from the last point
  89.             'referenced to the new point, using the old color.
  90.             IF PColor <> OldColor THEN
  91.                 LINE -(LogicX, LogicY), (ColorRange - OldColor)
  92.                 OldColor = PColor
  93.             END IF
  94.  
  95.             IF INKEY$ <> "" THEN END
  96.         NEXT X
  97.  
  98.         'Draw the last line segment to the right edge of the viewport.
  99.         LINE -(LogicX, LogicY), (ColorRange - OldColor)
  100.  
  101.     NEXT Y
  103.  
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