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Active Forums => QB64 Discussion => Topic started by: euklides on December 18, 2019, 05:00:16 am

Title: zoom on picture
Post by: euklides on December 18, 2019, 05:00:16 am
In your opinion, is there a way to zoom (to display an enlarged area) on a part of an picture ?
Thank you for your ideas on this subject.

Title: Re: zoom on picture
Post by: OldMoses on December 18, 2019, 07:00:50 am
I've used zooming functions in my vector tracker, but I haven't tried zooming on images. I think that _PUTIMAGE has the necessary parameters to do something like that.
Title: Re: zoom on picture
Post by: Petr on December 18, 2019, 08:28:55 am
Hi. Yes, _PUTIMAGE can this do, also MAPTRIANGLE can do it.

PUTIMAGE example:

Code: QB64: [Select]
  4.  
  6.     PCOPY 1, _DISPLAY
  8.     MX = _MOUSEX: MY = _MOUSEY
  9.     LINE (MX - 100, MY - 100)-(MX + 100, MY + 100), &HFFFFFFFF, B
  10.     '    _PUTIMAGE (MX - 99, MY - 99)-(MX + 99, MY + 99), img, 0, (MX - 50, MY - 50)-(MX + 50, MY + 50) 'zoom 2x
  11.     _PUTIMAGE (MX - 99, MY - 99)-(MX + 99, MY + 99), img, 0, (MX - 25, MY - 25)-(MX + 25, MY + 25) 'zoom 4x
  12.     _DISPLAY
  14.  
  15.  


and MAPTRIANGLE example:

Code: QB64: [Select]
  4.  
  6.     PCOPY 1, _DISPLAY
  8.     MX = _MOUSEX: MY = _MOUSEY
  9.     '     LINE (MX - 100, MY - 100)-(MX + 100, MY + 100), &HFFFFFFFF, B
  10.     '    _PUTIMAGE (MX - 99, MY - 99)-(MX + 99, MY + 99), img, 0, (MX - 50, MY - 50)-(MX + 50, MY + 50) 'zoom 2x
  11.     '    _PUTIMAGE (MX - 99, MY - 99)-(MX + 99, MY + 99), img, 0, (MX - 25, MY - 25)-(MX + 25, MY + 25) 'zoom 4x
  12.  
  13.     CIRCLE (MX, MY), 100, &HFFFFFFFF
  14.  
  15.     FOR circl = 0 TO _PI(2) STEP .02
  16.         dXa = MX + COS(circl) * 99
  17.         dYa = MY + SIN(circl) * 99
  18.  
  19.         dXb = MX + COS(circl + .02) * 99
  20.         dYb = MY + SIN(circl + .02) * 99
  21.  
  22.         dX1 = MX + COS(circl) * 30
  23.         dY1 = MY + SIN(circl) * 30
  24.  
  25.         dX2 = MX + COS(circl + .02) * 30
  26.         dY2 = MY + SIN(circl + .02) * 30
  27.  
  28.         '  zoom ratio is 30:99   ->  1 : 3,3
  29.         _MAPTRIANGLE (MX, MY)-(dX1, dY1)-(dX2, dY2), img TO(MX, MY)-(dXa, dYa)-(dXb, dYb), 0
  30.  
  31.     NEXT
  32.     _DISPLAY
  34.  
  35.  
Title: Re: zoom on picture
Post by: euklides on December 18, 2019, 11:58:41 am

Thank you Petr for your magnifying glass effect. 

Perhaps just I will need to use a square greater then 100 points.

Very nice !



Title: Re: zoom on picture
Post by: euklides on December 18, 2019, 12:13:34 pm

Ok, I tried. It works !!! And you can change the square size too.

But, how to quit the magnifying glass effect and go back to have the normal view of the picture (or the normal screen you had before this zoom effect) ?

Title: Re: zoom on picture
Post by: Petr on December 18, 2019, 12:48:40 pm
Quote
But, how to quit the magnifying glass effect and go back to have the normal view of the picture (or the normal screen you had before this zoom effect) ?



Code: QB64: [Select]
  3. PCOPY _DISPLAY, 1 '    save screen image as image page 1
  4.  
  5. DO UNTIL _KEYHIT = 32 'space for quit from zoom
  6.     PCOPY 1, _DISPLAY
  8.     MX = _MOUSEX: MY = _MOUSEY
  9.     LINE (MX - 100, MY - 100)-(MX + 100, MY + 100), &HFFFFFFFF, B
  10.     '    _PUTIMAGE (MX - 99, MY - 99)-(MX + 99, MY + 99), img, 0, (MX - 50, MY - 50)-(MX + 50, MY + 50) 'zoom 2x
  11.     _PUTIMAGE (MX - 99, MY - 99)-(MX + 99, MY + 99), img, 0, (MX - 25, MY - 25)-(MX + 25, MY + 25) 'zoom 4x
  12.     _DISPLAY
  14.  
  15. PCOPY 1, _DISPLAY 'return saved screen back
  16.  
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