use Writer.frink
// This program generates color illusions like this:
// http://www.johnsadowski.com/big_spanish_castle.php
inputURL = "file:DSC_0077.JPG"
img_in = new image[inputURL]
// Get file part of URL to use for output files.
origFile = urlFile[inputURL]
greyFile = origFile
greyFile =~ %s/(.*)\.\w+$/$1grey.jpg/
colorFile = origFile
colorFile =~ %s/(.*)\.\w+$/$1colors.jpg/
htmlFile = origFile
htmlFile =~ %s/(.*)\.\w+$/$1.html/
Width = img_in.getWidth[]
Height = img_in.getHeight[]
reverseImg = new image[Width, Height]
greyImg = new image[Width, Height]
for w = 0 to Width-1
{
for h = 0 to Height-1
{
[r,g,b] = img_in.getPixel[w, h]
// This converts to YUV space using the BT. 709 definition used in
// HDTV. See http://en.wikipedia.org/wiki/YUV
y = 0.2126 r + 0.7152 g + 0.0722 b
u = -0.09991 r - 0.33609 g + 0.436 b
v = 0.615 r - 0.55861 g - 0.05639 b
// Write out the grayscale levels.
greyImg.setPixel[w, h, y, y, y]
// Now we're going the throw away the Y (luminance) component
// and replace it with a constant 0.5. Then we're going to go back to
// RGB space and reverse the colors. We could simplify these equations
// but it's kinda nice to see them in this form.
y = 0.5
r = y + 0 u + 1.28033 v
g = y - 0.21482 u - 0.38059 v
b = y + 2.12798 u - 0 v
reverseImg.setPixel[w, h, 1-r, 1-g, 1-b]
}
}
g = new graphics
g.fitCenter[reverseImg, 0, 0, 1, 1]
g.drawEllipseCenter[0,0,0.005, 0.005]
//win = g.show[Width, Height]
g.write[colorFile, Width, Height]
g1 = new graphics
g1.fitCenter[greyImg, 0, 0, 1, 1]
g1.drawEllipseCenter[0,0,0.005, 0.005]
g1.write[greyFile, Width, Height]
// Render an interactive HTML file
println["htmlFile is $htmlFile"]
html = new Writer[htmlFile]
html.write["""
$htmlFile
Stare at the dot for 30 seconds, then move your mouse over the image.
"""]
html.close[]
println["Interactive file rendered to $htmlFile"]
// Start the interactive HTML file in the browser.
browse[htmlFile]
/*for i = 1 to 10
{
win.replaceGraphics[g1]
sleep[5 s]
win.replaceGraphics[g]
sleep[30 s]
}*/