Code archives/Graphics/Image color FX

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Image color FX by Matt Merkulov
(Posted 20 years ago)
From Blitz et cetera article
Image used:
;Image color FX by Matt Merkulov

Const k# = 180.0 / 255, k2# = 360.0 / 255, fx = 2
Dim col(2)

Graphics 640,480,32

i=LoadImage ("image1.jpg")
DrawBlock i, 0,0
For y=0 To 479
 For x=0 To 639
 p = ReadPixel (x, y)
 For n = 0 To 2
  c = p And 255
  p = p Shr 8
  Select fx
  Case 1; Negative
   c = 255 - c
  Case 2; Darkening
   c = c Shr 1
  Case 3; Lightening
   c = 128 + (c Sar 1)
  Case 4; Threshold
   c = 255 * (c >= 128)
  Case 5; Saturation reduction
   c = 64 + (c Sar 1)
  Case 6; Saturation increase
   c = c Shl 1 - 128
   If c < 0 Then c = 0
   If c > 255 Then c = 255
  Case 7; Square-law darkening
   c = 255 - Sqr(255 * 255 - c * c)
  Case 8; Square-law lightening
   c = 255 - c
   c = Sqr(255 * 255 - c * c)
  Case 9; Colors quantity reduction
   c = Int(c / 51) * 51
  Case 10; Saw
   c = (c Shr 6) * 4
  Case 11; Sawtooth
   If c And 64 Then c = 255 - (c And 63) * 4 Else c = (c And 63) * 4
  Case 12; Hollow
   c = 255 * (1 - Sin(c * k#))
  Case 13; Ledge
   c = 255 * Sin(c * k#)
  Case 14; Bend
   c = Sin(c * k2#) * 127 + c
  End Select
  col(n) =c
 Next
 WritePixel x, y, col(0) + col(1) Shl 8 + col(2) Shl 16 - 16777216
 Next
Next

WaitKey

Comments

Andy_A
(Posted 20 years ago)
Thanks Matjev,

The routines seem to work fine.

Don't really know what "the Saw","the Hollow","the Ledge","the Bend","Zubya" mean.

Try using simple words to describe then translate to English.

Here's another tranlator site: http://webtranslation.imtranslator.net/

Matt Merkulov
(Posted 20 years ago)
Take look at the graphs:

In fact, they're just funny fx, maybe not so useful as standard.

Andy_A
(Posted 20 years ago)
They are some of the same effects used in GIMP and Photoshop. Not the same code, but same effects, so they could be useful to someone.

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