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Bilinear interpolation: Difference between revisions
→{{header|Tcl}}: Added zkl
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</lang>
=={{header|zkl}}==
{{trans|C}}
Uses the PPM class from http://rosettacode.org/wiki/Bitmap/Bresenham%27s_line_algorithm#zkl.
Not fast enough to be called slow.
<lang zkl>fcn lerp(s,e,t){ s + (e-s)*t; }
fcn blerp(c00,c10,c01,c11, tx,ty){ lerp(lerp(c00,c10,tx), lerp(c01,c11,tx),ty) }
fcn scale(src, scaleX,scaleY){
newWidth,newHeight := Int(scaleX*src.w), Int(scaleY*src.h);
dst:=PPM(newWidth,newHeight);
foreach y,x in ([0.0..newHeight-1],[0.0..newWidth-1]){
gx:=x/newWidth *(src.w-1);
gy:=y/newHeight *(src.h-1);
gxi,gyi:=Int(gx), Int(gy);
// cxy=RGB, cxy.toBigEndian(3)-->(R,G,B)
c00,c10 := src[gxi,gyi].toBigEndian(3), src[gxi+1,gyi].toBigEndian(3);
c01 := src[gxi,gyi+1] .toBigEndian(3);
c11 := src[gxi+1,gyi+1].toBigEndian(3);
dst[x,y] = (3).pump(Data(), // Data is a byte bucket
'wrap(i){ blerp(c00[i],c10[i],c01[i],c11[i], gx-gxi, gy-gyi) })
.toBigEndian(0,3);
}
dst
}</lang>
<lang zkl>img:=PPM.readPPMFile("lena.ppm");
img=scale(img,1.5,1.5);
img.write(File("lena1.5.ppm","wb"));</lang>
{{out}}
http://home.comcast.net/~zenkinetic/Images/2Lenas.jpg
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