[bb] Gradient Fill Image by Grey Alien [ 1+ years ago ]

[BlitzBot]

Title : Gradient Fill Image
Author : Grey Alien
Posted : 1+ years ago

Description : This code can be used to gradient fill and image from top to bottom.

Code :

Code (blitzbasic) Select Expand

; -----------------------------------------------------------------------------
; ccGradientFill
; -----------------------------------------------------------------------------
Function ccGradientFill(Temp%, SourceCol%, StartCol%, EndCol%)
;temp is an image
;-1 ($ffffffff) is white (good for sourcecol)
SetBuffer ImageBuffer(Temp)
LockBuffer ImageBuffer(Temp)

Local x
Local y#
Local col = 0

For y = 0 To ImageHeight(Temp)-1
col = ccBlendColours(StartCol, EndCol, y/ImageHeight(Temp))
For x = 0 To ImageWidth(Temp)-1
r = ReadPixelFast(x, y)
If r = SourceCol Then
WritePixelFast(x, y, col)
EndIf
Next
Next

UnlockBuffer ImageBuffer(Temp)

;don't reset buffer, calling proc must do it if it wants to.
End Function

; -----------------------------------------------------------------------------
; ccBlendColours
; -----------------------------------------------------------------------------
Function ccBlendColours%(st%, en%, ratio#)
;use RGB values adjusted with ARGB_Black
;ratio# must be 0 to 1
Rst = (st Shr 16) And 255
Gst = (st Shr 8 ) And 255
Bst = st And 255

Ren = (en Shr 16) And 255
Gen = (en Shr 8 ) And 255
Ben = en And 255

Rdiff=  Rst-Ren
Gdiff=  Gst-Gen
Bdiff=  Bst-Ben

Rdiff = Rdiff * ratio#
Gdiff = Gdiff * ratio#
Bdiff = Bdiff * ratio#

Return (((Rst-Rdiff) Shl 16) Or ((Gst-Gdiff) Shl 8) Or (Bst-Bdiff))
End Function

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