27 lines
840 B
JavaScript
27 lines
840 B
JavaScript
// draw an arc between radii minR and maxR, and between angles minAngle and maxAngle
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exports.drawArc = function(graphics, minR, maxR, minAngle, maxAngle) {
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var step = stepAngle;
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var angle = minAngle;
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var inside = [];
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var outside = [];
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var c, s;
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while (angle < maxAngle) {
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c = Math.cos(angle);
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s = Math.sin(angle);
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inside.push(centreX+c*minR); // x
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inside.push(centreY+s*minR); // y
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// outside coordinates are built up in reverse order
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outside.unshift(centreY+s*maxR); // y
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outside.unshift(centreX+c*maxR); // x
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angle += step;
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}
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c = Math.cos(maxAngle);
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s = Math.sin(maxAngle);
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inside.push(centreX+c*minR);
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inside.push(centreY+s*minR);
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outside.unshift(centreY+s*maxR);
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outside.unshift(centreX+c*maxR);
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var vertices = inside.concat(outside);
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graphics.fillPoly(vertices, true);
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} |