64 lines
1.6 KiB
JavaScript
64 lines
1.6 KiB
JavaScript
// Copyright (C) 2016 The Qt Company Ltd.
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// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
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.pragma library
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function renderSmoothedLine(ctx, trace, renderPos) {
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if (!trace)
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return renderPos
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if (renderPos >= trace.length)
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return renderPos
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// Fetch points and draw the initial "dot"
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var points, tp
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if (renderPos === 0) {
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points = trace.points()
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tp = points[renderPos++]
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ctx.beginPath()
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ctx.moveTo(tp.x, tp.y)
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ctx.lineTo(tp.x, tp.y + 0.000001)
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ctx.stroke()
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} else {
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points = trace.points(renderPos - 1)
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}
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// Draw smoothed line using quadratic curve
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var i = 1
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if (i + 1 < points.length) {
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var pt1, pt2
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if (renderPos === 1) {
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tp = points[i - 1]
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} else {
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pt1 = points[i - 1]
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pt2 = points[i]
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tp = Qt.point((pt1.x + pt2.x) / 2, (pt1.y + pt2.y) / 2)
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}
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ctx.beginPath()
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ctx.moveTo(tp.x, tp.y)
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while (i + 1 < points.length) {
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pt1 = points[i++]
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pt2 = points[i]
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tp = Qt.point((pt1.x + pt2.x) / 2, (pt1.y + pt2.y) / 2)
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ctx.quadraticCurveTo(pt1.x, pt1.y, tp.x, tp.y)
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ctx.moveTo(tp.x, tp.y)
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}
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ctx.stroke()
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}
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// Draw the remainder of the line
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if (trace.final) {
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if (i < points.length) {
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tp = points[i - 1]
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ctx.beginPath()
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ctx.moveTo(tp.x, tp.y)
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tp = points[i++]
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ctx.lineTo(tp.x, tp.y)
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ctx.stroke()
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}
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}
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return renderPos + i - 1
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}
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