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https://github.com/scratchfoundation/paper.js.git
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Use quality factor for better winding calculation and propagation
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iconexperience
parent
ed38634a80
commit
3c2588fdec
2 changed files with 94 additions and 97 deletions
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@ -412,11 +412,8 @@ PathItem.inject(new function() {
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paR = pa + epsilon,
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windingL = 0,
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windingR = 0,
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pathWindingL = 0,
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pathWindingR = 0,
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onPath = false,
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onPathWinding = 0,
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onPathCount = 0,
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quality = 1,
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roots = [],
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vPrev,
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vClose;
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@ -440,7 +437,7 @@ PathItem.inject(new function() {
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// +-----+
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// +----+ |
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// +-----+
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if (a1 < paR && a3 > paL || a3 < paR && a1 > paL) {
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if (a0 < paR && a3 > paL || a3 < paR && a0 > paL) {
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onPath = true;
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}
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// If curve does not change in ordinate direction, windings will
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@ -461,25 +458,22 @@ PathItem.inject(new function() {
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winding = o0 > o3 ? 1 : -1,
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windingPrev = vPrev[io] > vPrev[io + 6] ? 1 : -1,
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a3Prev = vPrev[ia + 6];
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if (a >= paL && a <= paR) onPath = true;
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if (po !== o0) {
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// Standard case, curve is not crossed at its starting point.
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if (a < paL) {
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pathWindingL += winding;
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windingL += winding;
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} else if (a > paR) {
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pathWindingR += winding;
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} else {
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onPath = true;
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pathWindingL += winding;
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pathWindingR += winding;
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windingR += winding;
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}
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} else if (winding !== windingPrev) {
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// Curve is crossed at starting point and winding changes from
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// previous curve. Cancel the winding from previous curve.
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if (a3Prev < paR) {
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pathWindingL += winding;
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windingL += winding;
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}
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if (a3Prev > paL) {
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pathWindingR += winding;
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windingR += winding;
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}
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} else if (a3Prev < paL && a > paL || a3Prev > paR && a < paR) {
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// Point is on a horizontal curve between the previous non-
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@ -487,12 +481,26 @@ PathItem.inject(new function() {
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onPath = true;
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if (a3Prev < paL) {
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// left winding was added before, now add right winding.
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pathWindingR += winding;
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windingR += winding;
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} else if (a3Prev > paR) {
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// right winding was added before, not add left winding.
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pathWindingL += winding;
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// right winding was added before, now add left winding.
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windingL += winding;
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}
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}
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// Determine the quality of the winding calculation. Currently the
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// quality is reduced with every crossing of the ray very close
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// to the path. This means that if the point is on or near multiple
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// curves, the quality becomes less than 0.5
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//ToDo Set quality depending on distance
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if (po !== o0) {
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if (a > pa - 100 * epsilon && a < pa + 100 * epsilon) {
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//quality *= Math.min(1, (100 * epsilon * Math.abs(a - pa) + 0.5));
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quality /= 2;
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}
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} else {
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//ToDo:
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quality = 0;
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}
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vPrev = v;
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// If we're on the curve, look at the tangent to decide whether to
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// flip direction to better determine a reliable winding number:
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@ -586,31 +594,10 @@ PathItem.inject(new function() {
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// it now to treat the path as closed:
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if (vClose && (res = handleCurve(vClose)))
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return res;
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if (onPath && !pathWindingL && !pathWindingR) {
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// If the point is on the path and the windings canceled
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// each other, we treat the point as if it was inside the
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// path. A point inside a path has a winding of [+1,-1]
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// for clockwise and [-1,+1] for counter-clockwise paths.
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// If the ray is cast in y direction (dir == 1), the
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// windings always have opposite sign.
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var add = path.isClockwise(closed) ^ dir ? 1 : -1;
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windingL += add;
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windingR -= add;
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onPathWinding += add;
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} else {
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windingL += pathWindingL;
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windingR += pathWindingR;
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pathWindingL = pathWindingR = 0;
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}
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if (onPath)
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onPathCount++;
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onPath = false;
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vClose = null;
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}
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}
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if (!windingL && !windingR) {
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windingL = windingR = onPathWinding;
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}
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// If the winding one
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windingL = windingL && (2 - abs(windingL) % 2);
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windingR = windingR && (2 - abs(windingR) % 2);
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// Return the calculated winding contribution and detect if we are
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@ -622,7 +609,8 @@ PathItem.inject(new function() {
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windingL: windingL,
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windingR: windingR,
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onContour: !windingL ^ !windingR,
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onPathCount: onPathCount
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onPath: onPath,
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quality: quality
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};
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}
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@ -642,8 +630,12 @@ PathItem.inject(new function() {
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totalLength += length;
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segment = segment.getNext();
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} while (segment && !segment._intersection && segment !== start);
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// Sample the point at a middle of the chain to get its winding:
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var length = totalLength / 2;
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// Determine winding at three points in the chain. If a winding with
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// sufficient quality is found, use it. Otherwise use the winding with
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// the best quality.
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var offsets = [0.48, 0.1, 0.9];
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for (var i = 0; (!winding || winding.quality < 0.5) && i < offsets.length; i++) {
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var length = totalLength * offsets[i];
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for (var j = 0, l = chain.length; j < l; j++) {
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var entry = chain[j],
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curveLength = entry.length;
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@ -664,17 +656,22 @@ PathItem.inject(new function() {
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// While subtracting, we need to omit this curve if it is
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// contributing to the second operand and is outside the
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// first operand.
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winding = !(operator.subtract && path2 && (
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var windingNew = !(operator.subtract && path2 && (
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path === path1 &&
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path2._getWinding(pt, dir, true).winding ||
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path === path2 &&
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!path1._getWinding(pt, dir, true).winding))
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? getWinding(pt, curves, dir, true)
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: { winding: 0 };
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: {winding: 0};
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if (windingNew.winding != 0 &&
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(!winding || winding.quality < windingNew.quality)) {
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winding = windingNew;
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}
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break;
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}
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length -= curveLength;
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}
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}
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// Now assign the winding to the entire curve chain.
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for (var j = chain.length - 1; j >= 0; j--) {
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chain[j].segment._winding = winding;
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@ -256,7 +256,7 @@ var PathItem = Item.extend(/** @lends PathItem# */{
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_contains: function(point) {
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// NOTE: point is reverse transformed by _matrix, so we don't need to
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// apply the matrix here.
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/*#*/ if (__options.nativeContains || !__options.booleanOperations) {
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/*#*/ if (__options.nativeContains || !__options.booleanOperations) {
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// To compare with native canvas approach:
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var ctx = CanvasProvider.getContext(1, 1);
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// Use dontFinish to tell _draw to only produce geometries for hit-test.
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@ -264,7 +264,7 @@ var PathItem = Item.extend(/** @lends PathItem# */{
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var res = ctx.isPointInPath(point.x, point.y, this.getFillRule());
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CanvasProvider.release(ctx);
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return res;
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/*#*/ } else { // !__options.nativeContains && __options.booleanOperations
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/*#*/ } else { // !__options.nativeContains && __options.booleanOperations
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// Check the transformed point against the untransformed (internal)
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// handle bounds, which is the fastest rough bounding box to calculate
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// for a quick check before calculating the actual winding.
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@ -272,10 +272,10 @@ var PathItem = Item.extend(/** @lends PathItem# */{
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this.getBounds({ internal: true, handle: true }))
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? this._getWinding(point)
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: {};
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return !!(this.getFillRule() === 'evenodd'
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return winding.onPath || !!(this.getFillRule() === 'evenodd'
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? winding.windingL & 1 || winding.windingR & 1
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: winding.winding);
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/*#*/ } // !__options.nativeContains && __options.booleanOperations
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/*#*/ } // !__options.nativeContains && __options.booleanOperations
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},
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/**
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