Image color FX

This code has been declared by its author to be Public Domain code.

Image color FX by Matt Merkulov

2007

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

2007

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

2007

Take look at the graphs:

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

Andy_A

2007

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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