GetColor() and RGB

BlitzMax Forums/BlitzMax Programming/GetColor() and RGB

ErikT

(Posted 2010) [#1]

Hello everybody! I'm writing a scaling function based on the Scale2X and RotSprite algorithms:

http://en.wikipedia.org/wiki/Pixel_art_scaling_algorithms

I've got the scale2X bit running so far but I want to improve the blending by having it check for pixels similar to eachother and not just equal ones. To do that I really need to get to the separate RGB values somehow. GetColor just plops all that info into a single variable so is there any other way to do this?

xlsior

(Posted 2010) [#2]

You'll have to seperate the red, green and blue values based on the GetColor result:
Local Red:int = (Color Shr 16) & $FF
Local Green:int = (Color Shr 8) & $FF
Local Blue:Int = Color & $FF

GfK	(Posted 2010) [#3]

GetColor returns separate RGB values for the current color.

Are you sure you didn't mean ReadPixel?

Assuming you did, this [untested] should work:

Color:Int = ReadPixel(x,y)

Red:Int = (Color & $FF0000) Shr 16
Green:Int = (Color & $FF00) Shr 8
Blue:Int = (color & $FF)

ErikT

(Posted 2010) [#4]

That's what I meant. Thanks :o)

ErikT

(Posted 2010) [#5]

Here's the code so far if anyone wants to play around with it.



Function Scale_and_Interpolate()

	Local Pixmap:TPixmap = LoadPixmap("C:\input2.bmp")
	Local ScaledPixmap:TPixmap = CreatePixmap(256,256,PF_RGB888)
	Local Pix_W:Int = PixmapWidth(Pixmap)
	Local Pix_H:Int = PixmapHeight(Pixmap)

	Local P:Int
	Local A:Int
	Local B:Int
	Local C:Int
	Local D:Int


	For x = 0 To Pix_W - 1
		For y = 0 To Pix_H - 1

			P = ReadPixel(Pixmap,x,y)
			If x > 0 And x < Pix_W - 1 And y > 0 And y < Pix_H - 1
				A = ReadPixel(Pixmap,x,y-1)
				B = ReadPixel(Pixmap,x+1,y)
				C = ReadPixel(Pixmap,x-1,y)
				D = ReadPixel(Pixmap,x,y+1)
			Else
				A = P
				B = P
				C = P
				D = P
			EndIf

			P_1 = P
			P_2 = P
			P_3 = P
			P_4 = P
			If A = C And B <> D And A <> B Then P_1 = A
			If A = B And A <> C And B <> D Then P_2 = B
			If D = C And B <> D And C <> A Then P_3 = C
			If B = D And B <> A And D <> C Then P_4 = D

			WritePixel(ScaledPixmap,x*2,y*2,P_1)
			WritePixel(ScaledPixmap,(x*2)+1,y*2,P_2)
			WritePixel(ScaledPixmap,x*2,(y*2)+1,P_3)
			WritePixel(ScaledPixmap,(x*2)+1,(y*2)+1,P_4)
		Next
	Next

	TestImg = LoadImage(ScaledPixmap)

End Function



Global TestImg:TImage


Graphics 640,480

Scale_and_Interpolate()

While Not KeyDown(KEY_ESCAPE)

	Cls
		DrawImage(TestImg,0,0)
	Flip

Wend

End

Last edited 2010