285 lines
12 KiB
JavaScript
285 lines
12 KiB
JavaScript
/**
|
|
* Copyright (c) 2015 Guyon Roche
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
* of this software and associated documentation files (the "Software"), to deal
|
|
* in the Software without restriction, including without limitation the rights
|
|
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
* copies of the Software, and to permit persons to whom the Software is
|
|
* furnished to do so, subject to the following conditions:</p>
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in
|
|
* all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
* THE SOFTWARE.
|
|
*
|
|
*/
|
|
"use strict";
|
|
|
|
module.exports = {
|
|
nearestNeighbor: function(src, dst, options) {
|
|
|
|
var wSrc = src.width;
|
|
var hSrc = src.height;
|
|
//console.log("wSrc="+wSrc + ", hSrc="+hSrc);
|
|
|
|
var wDst = dst.width;
|
|
var hDst = dst.height;
|
|
//console.log("wDst="+wDst + ", hDst="+hDst);
|
|
|
|
var bufSrc = src.data;
|
|
var bufDst = dst.data;
|
|
|
|
for (var i = 0; i < hDst; i++) {
|
|
for (var j = 0; j < wDst; j++) {
|
|
var posDst = (i * wDst + j) * 4;
|
|
|
|
var iSrc = Math.round(i * hSrc / hDst);
|
|
var jSrc = Math.round(j * wSrc / wDst);
|
|
var posSrc = (iSrc * wSrc + jSrc) * 4;
|
|
|
|
bufDst[posDst++] = bufSrc[posSrc++];
|
|
bufDst[posDst++] = bufSrc[posSrc++];
|
|
bufDst[posDst++] = bufSrc[posSrc++];
|
|
bufDst[posDst++] = bufSrc[posSrc++];
|
|
}
|
|
}
|
|
},
|
|
bilinearInterpolation: function(src, dst, options) {
|
|
|
|
var wSrc = src.width;
|
|
var hSrc = src.height;
|
|
//console.log("wSrc="+wSrc + ", hSrc="+hSrc);
|
|
|
|
var wDst = dst.width;
|
|
var hDst = dst.height;
|
|
//console.log("wDst="+wDst + ", hDst="+hDst);
|
|
|
|
var bufSrc = src.data;
|
|
var bufDst = dst.data;
|
|
|
|
var interpolate = function(k, kMin, vMin, kMax, vMax) {
|
|
// special case - k is integer
|
|
if (kMin === kMax) {
|
|
return vMin;
|
|
}
|
|
|
|
return Math.round((k - kMin) * vMax + (kMax - k) * vMin);
|
|
};
|
|
var assign = function(pos, offset, x, xMin, xMax, y, yMin, yMax) {
|
|
var posMin = (yMin * wSrc + xMin) * 4 + offset;
|
|
var posMax = (yMin * wSrc + xMax) * 4 + offset;
|
|
var vMin = interpolate(x, xMin, bufSrc[posMin], xMax, bufSrc[posMax]);
|
|
|
|
// special case, y is integer
|
|
if (yMax === yMin) {
|
|
bufDst[pos+offset] = vMin;
|
|
} else {
|
|
posMin = (yMax * wSrc + xMin) * 4 + offset;
|
|
posMax = (yMax * wSrc + xMax) * 4 + offset;
|
|
var vMax = interpolate(x, xMin, bufSrc[posMin], xMax, bufSrc[posMax]);
|
|
|
|
bufDst[pos+offset] = interpolate(y, yMin, vMin, yMax, vMax);
|
|
}
|
|
}
|
|
|
|
for (var i = 0; i < hDst; i++) {
|
|
for (var j = 0; j < wDst; j++) {
|
|
var posDst = (i * wDst + j) * 4;
|
|
|
|
// x & y in src coordinates
|
|
var x = j * wSrc / wDst;
|
|
var xMin = Math.floor(x);
|
|
var xMax = Math.min(Math.ceil(x), wSrc-1);
|
|
|
|
var y = i * hSrc / hDst;
|
|
var yMin = Math.floor(y);
|
|
var yMax = Math.min(Math.ceil(y), hSrc-1);
|
|
|
|
assign(posDst, 0, x, xMin, xMax, y, yMin, yMax);
|
|
assign(posDst, 1, x, xMin, xMax, y, yMin, yMax);
|
|
assign(posDst, 2, x, xMin, xMax, y, yMin, yMax);
|
|
assign(posDst, 3, x, xMin, xMax, y, yMin, yMax);
|
|
}
|
|
}
|
|
},
|
|
|
|
_interpolate2D: function(src, dst, options, interpolate) {
|
|
|
|
var bufSrc = src.data;
|
|
var bufDst = dst.data;
|
|
|
|
var wSrc = src.width;
|
|
var hSrc = src.height;
|
|
//console.log("wSrc="+wSrc + ", hSrc="+hSrc + ", srcLen="+bufSrc.length);
|
|
|
|
var wDst = dst.width;
|
|
var hDst = dst.height;
|
|
//console.log("wDst="+wDst + ", hDst="+hDst + ", dstLen="+bufDst.length);
|
|
|
|
// when dst smaller than src/2, interpolate first to a multiple between 0.5 and 1.0 src, then sum squares
|
|
var wM = Math.max(1, Math.floor(wSrc / wDst));
|
|
var wDst2 = wDst * wM;
|
|
var hM = Math.max(1, Math.floor(hSrc / hDst));
|
|
var hDst2 = hDst * hM;
|
|
//console.log("wM="+wM + ", wDst2="+wDst2 + ", hM="+hM + ", hDst2="+hDst2);
|
|
|
|
// ===========================================================
|
|
// Pass 1 - interpolate rows
|
|
// buf1 has width of dst2 and height of src
|
|
var buf1 = new Buffer(wDst2 * hSrc * 4);
|
|
for (var i = 0; i < hSrc; i++) {
|
|
for (var j = 0; j < wDst2; j++) {
|
|
// i in src coords, j in dst coords
|
|
|
|
// calculate x in src coords
|
|
// this interpolation requires 4 sample points and the two inner ones must be real
|
|
// the outer points can be fudged for the edges.
|
|
// therefore (wSrc-1)/wDst2
|
|
var x = j * (wSrc-1) / wDst2;
|
|
var xPos = Math.floor(x);
|
|
var t = x - xPos;
|
|
var srcPos = (i * wSrc + xPos) * 4;
|
|
|
|
var buf1Pos = (i * wDst2 + j) * 4;
|
|
for (var k = 0; k < 4; k++) {
|
|
var kPos = srcPos + k;
|
|
var x0 = (xPos > 0) ? bufSrc[kPos - 4] : 2*bufSrc[kPos]-bufSrc[kPos+4];
|
|
var x1 = bufSrc[kPos];
|
|
var x2 = bufSrc[kPos + 4];
|
|
var x3 = (xPos < wSrc - 2) ? bufSrc[kPos + 8] : 2*bufSrc[kPos + 4]-bufSrc[kPos];
|
|
buf1[buf1Pos+k] = interpolate(x0,x1,x2,x3,t);
|
|
}
|
|
}
|
|
}
|
|
//this._writeFile(wDst2, hSrc, buf1, "out/buf1.jpg");
|
|
|
|
// ===========================================================
|
|
// Pass 2 - interpolate columns
|
|
// buf2 has width and height of dst2
|
|
var buf2 = new Buffer(wDst2 * hDst2 * 4);
|
|
for (var i = 0; i < hDst2; i++) {
|
|
for (var j = 0; j < wDst2; j++) {
|
|
// i&j in dst2 coords
|
|
|
|
// calculate y in buf1 coords
|
|
// this interpolation requires 4 sample points and the two inner ones must be real
|
|
// the outer points can be fudged for the edges.
|
|
// therefore (hSrc-1)/hDst2
|
|
var y = i * (hSrc-1) / hDst2;
|
|
var yPos = Math.floor(y);
|
|
var t = y - yPos;
|
|
var buf1Pos = (yPos * wDst2 + j) * 4;
|
|
var buf2Pos = (i * wDst2 + j) * 4;
|
|
for (var k = 0; k < 4; k++) {
|
|
var kPos = buf1Pos + k;
|
|
var y0 = (yPos > 0) ? buf1[kPos - wDst2*4] : 2*buf1[kPos]-buf1[kPos + wDst2*4];
|
|
var y1 = buf1[kPos];
|
|
var y2 = buf1[kPos + wDst2*4];
|
|
var y3 = (yPos < hSrc-2) ? buf1[kPos + wDst2*8] : 2*buf1[kPos + wDst2*4]-buf1[kPos];
|
|
|
|
buf2[buf2Pos + k] = interpolate(y0,y1,y2,y3,t);
|
|
}
|
|
}
|
|
}
|
|
//this._writeFile(wDst2, hDst2, buf2, "out/buf2.jpg");
|
|
|
|
// ===========================================================
|
|
// Pass 3 - scale to dst
|
|
var m = wM * hM;
|
|
if (m > 1) {
|
|
for (var i = 0; i < hDst; i++) {
|
|
for (var j = 0; j < wDst; j++) {
|
|
// i&j in dst bounded coords
|
|
var r = 0;
|
|
var g = 0;
|
|
var b = 0;
|
|
var a = 0;
|
|
var realColors = 0;
|
|
for (var y = 0; y < hM; y++) {
|
|
var yPos = i * hM + y;
|
|
for (var x = 0; x < wM; x++) {
|
|
var xPos = j * wM + x;
|
|
var xyPos = (yPos * wDst2 + xPos) * 4;
|
|
var pixelAplha = buf2[xyPos+3];
|
|
|
|
if (pixelAplha) {
|
|
r += buf2[xyPos];
|
|
g += buf2[xyPos+1];
|
|
b += buf2[xyPos+2];
|
|
realColors++;
|
|
}
|
|
|
|
a += pixelAplha;
|
|
}
|
|
}
|
|
|
|
var pos = (i*wDst + j) * 4;
|
|
bufDst[pos] = realColors ? Math.round(r / realColors) : 0;
|
|
bufDst[pos+1] = realColors ? Math.round(g / realColors) : 0;
|
|
bufDst[pos+2] = realColors ? Math.round(b / realColors) : 0;
|
|
bufDst[pos+3] = Math.round(a / m);
|
|
}
|
|
}
|
|
} else {
|
|
// replace dst buffer with buf2
|
|
dst.data = buf2;
|
|
}
|
|
},
|
|
|
|
bicubicInterpolation: function(src, dst, options) {
|
|
var interpolateCubic = function(x0, x1, x2, x3, t) {
|
|
var a0 = x3 - x2 - x0 + x1;
|
|
var a1 = x0 - x1 - a0;
|
|
var a2 = x2 - x0;
|
|
var a3 = x1;
|
|
return Math.max(0,Math.min(255,(a0 * (t * t * t)) + (a1 * (t * t)) + (a2 * t) + (a3)));
|
|
}
|
|
return this._interpolate2D(src, dst, options, interpolateCubic);
|
|
},
|
|
|
|
hermiteInterpolation: function(src, dst, options) {
|
|
var interpolateHermite = function(x0, x1, x2, x3, t)
|
|
{
|
|
var c0 = x1;
|
|
var c1 = 0.5 * (x2 - x0);
|
|
var c2 = x0 - (2.5 * x1) + (2 * x2) - (0.5 * x3);
|
|
var c3 = (0.5 * (x3 - x0)) + (1.5 * (x1 - x2));
|
|
return Math.max(0,Math.min(255,Math.round((((((c3 * t) + c2) * t) + c1) * t) + c0)));
|
|
}
|
|
return this._interpolate2D(src, dst, options, interpolateHermite);
|
|
},
|
|
|
|
bezierInterpolation: function(src, dst, options) {
|
|
// between 2 points y(n), y(n+1), use next points out, y(n-1), y(n+2)
|
|
// to predict control points (a & b) to be placed at n+0.5
|
|
// ya(n) = y(n) + (y(n+1)-y(n-1))/4
|
|
// yb(n) = y(n+1) - (y(n+2)-y(n))/4
|
|
// then use std bezier to interpolate [n,n+1)
|
|
// y(n+t) = y(n)*(1-t)^3 + 3 * ya(n)*(1-t)^2*t + 3 * yb(n)*(1-t)*t^2 + y(n+1)*t^3
|
|
// note the 3* factor for the two control points
|
|
// for edge cases, can choose:
|
|
// y(-1) = y(0) - 2*(y(1)-y(0))
|
|
// y(w) = y(w-1) + 2*(y(w-1)-y(w-2))
|
|
// but can go with y(-1) = y(0) and y(w) = y(w-1)
|
|
var interpolateBezier = function(x0, x1, x2, x3, t) {
|
|
// x1, x2 are the knots, use x0 and x3 to calculate control points
|
|
var cp1 = x1 + (x2-x0)/4;
|
|
var cp2 = x2 - (x3-x1)/4;
|
|
var nt = 1-t;
|
|
var c0 = x1 * nt * nt * nt;
|
|
var c1 = 3 * cp1 * nt * nt * t;
|
|
var c2 = 3 * cp2 * nt * t * t;
|
|
var c3 = x2 * t * t * t;
|
|
return Math.max(0,Math.min(255,Math.round(c0 + c1 + c2 + c3)));
|
|
}
|
|
return this._interpolate2D(src, dst, options, interpolateBezier);
|
|
}
|
|
}
|