Download or view FloydSteinbergDither.frink in plain text format
// Floyd-Steinberg dithering test
// This program takes an image and turns it into something that could display
// on a TRS-80 Model I,III,or 4. 128x48, black and white, baby.
//i = new image["https://futureboy.us/images/futureboydomethumb4.gif"]
//i=new image["http://www.foxnews.com/images/302417/0_61_mckellar_danica.jpg"]
//i=new image["http://www.gossipboulevard.com/wp-content/uploads/2009/02/danica-mckellar2.jpg"]
//i=new image["http://www.gossipboulevard.com/wp-content/uploads/2009/02/danica-mckellar1-150x150.jpg"]
if (length[ARGS] > 0)
i = new image["file:" + ARGS@0]
else
i=new image["https://futureboy.us/images/futureboydomethumb4.gif"]
i.show[]
i.show[]
w = i.getWidth[]
h = i.getHeight[]
pw = 128
ph = 48
xstep = w/pw
ystep = h/ph
ni = new image[pw,ph]
// Create a grayscale version of the image.
xx = 0
for x=0 to w-xstep step xstep
{
yy = 0
for y = 0 to h-ystep step ystep
{
[r,g,b,a] = i.averagePixels[x,y,x+xstep, y+ystep]
gray = (r+g+b)/3
ni.setPixel[xx,yy,gray,gray,gray,a]
yy = yy + 1
}
xx = xx + 1
}
rerror = 0
gerror = 0
berror = 0
gr = new graphics
gr.backgroundColor[0,0,0]
for x = 0 to pw-1
for y = 0 to ph-1
{
[r,g,b,a] = ni.getPixel[x,y]
gray = (r+g+b) / 3
if gray > 1/2
c = 1
else
c = 0
err = gray - c
ni.setPixel[x,y,c,c,c,a]
gr.color[c,c,c,a]
gr.fillRectCenter[x,y*2,1,2]
addError[ni, x+1, y, 7/16, err]
addError[ni, x-1, y+1, 3/16, err]
addError[ni, x, y+1, 5/16, err]
addError[ni, x+1, y+1, 1/16, err]
}
ni.show[]
gr.show[]
// println["$r $g $b $a"]
// gr.color[c,c,c,a]
// gr.fillRectCenter[x,y,xstep,ystep]
// gr.fillEllipseCenter[x,y,xstep,ystep]
// gr.text["\u03c0",x,y]
//i.show[]
//gr.show[]
addError[image, x, y, mult, err] :=
{
if (x<0) || (y<0) || (x>=image.getWidth[]) || (y>=image.getHeight[])
return
[r,g,b,a] = image.getPixel[x,y]
r = clamp[r+mult*err]
g = clamp[g+mult*err]
b = clamp[b+mult*err]
image.setPixel[x,y,r,g,b,a]
}
clamp[v, min=0, max=1] :=
{
if v < min
min
else
if v > max
max
else
v
}
Download or view FloydSteinbergDither.frink in plain text format
This is a program written in the programming language Frink.
For more information, view the Frink
Documentation or see More Sample Frink Programs.
Alan Eliasen was born 19981 days, 19 hours, 22 minutes ago.