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| var LN2 = Math.log(2);
| function determinant(rows, rank, rowStart, rowMask, colMask, detCache) {
| var cacheKey = rowMask + '-' + colMask;
| var fullRank = rows.length;
| if (detCache.hasOwnProperty(cacheKey)) {
| return detCache[cacheKey];
| }
| if (rank === 1) {
| var colStart = Math.round(Math.log(((1 << fullRank) - 1) & ~colMask) / LN2);
| return rows[rowStart][colStart];
| }
| var subRowMask = rowMask | (1 << rowStart);
| var subRowStart = rowStart + 1;
| while (rowMask & (1 << subRowStart)) {
| subRowStart++;
| }
| var sum = 0;
| for (var j = 0, colLocalIdx = 0; j < fullRank; j++) {
| var colTag = 1 << j;
| if (!(colTag & colMask)) {
| sum += (colLocalIdx % 2 ? -1 : 1) * rows[rowStart][j]
| * determinant(rows, rank - 1, subRowStart, subRowMask, colMask | colTag, detCache);
| colLocalIdx++;
| }
| }
| detCache[cacheKey] = sum;
| return sum;
| }
| export function buildTransformer(src, dest) {
| var mA = [
| [src[0], src[1], 1, 0, 0, 0, -dest[0] * src[0], -dest[0] * src[1]],
| [0, 0, 0, src[0], src[1], 1, -dest[1] * src[0], -dest[1] * src[1]],
| [src[2], src[3], 1, 0, 0, 0, -dest[2] * src[2], -dest[2] * src[3]],
| [0, 0, 0, src[2], src[3], 1, -dest[3] * src[2], -dest[3] * src[3]],
| [src[4], src[5], 1, 0, 0, 0, -dest[4] * src[4], -dest[4] * src[5]],
| [0, 0, 0, src[4], src[5], 1, -dest[5] * src[4], -dest[5] * src[5]],
| [src[6], src[7], 1, 0, 0, 0, -dest[6] * src[6], -dest[6] * src[7]],
| [0, 0, 0, src[6], src[7], 1, -dest[7] * src[6], -dest[7] * src[7]]
| ];
| var detCache = {};
| var det = determinant(mA, 8, 0, 0, 0, detCache);
| if (det === 0) {
| return;
| }
| var vh = [];
| for (var i = 0; i < 8; i++) {
| for (var j = 0; j < 8; j++) {
| vh[j] == null && (vh[j] = 0);
| vh[j] += ((i + j) % 2 ? -1 : 1)
| * determinant(mA, 7, i === 0 ? 1 : 0, 1 << i, 1 << j, detCache)
| / det * dest[i];
| }
| }
| return function (out, srcPointX, srcPointY) {
| var pk = srcPointX * vh[6] + srcPointY * vh[7] + 1;
| out[0] = (srcPointX * vh[0] + srcPointY * vh[1] + vh[2]) / pk;
| out[1] = (srcPointX * vh[3] + srcPointY * vh[4] + vh[5]) / pk;
| };
| }
|
|
