30 lines
785 B
JavaScript
30 lines
785 B
JavaScript
exports.transformPoint = function(tfm, pt){
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return {
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x : pt.x * tfm.xx + pt.y * tfm.yx + tfm.x,
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y : pt.x * tfm.xy + pt.y * tfm.yy + tfm.y,
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onCurve: pt.onCurve,
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cubic: pt.cubic
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}
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}
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exports.inverse = function(tfm){
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var denom = tfm.xx * tfm.yy - tfm.xy * tfm.yx;
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return {
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xx : tfm.yy / denom,
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yx : -tfm.yx / denom,
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xy : -tfm.xy / denom,
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yy : tfm.xx / denom,
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x : -(tfm.x * tfm.yy - tfm.y * tfm.yx) / denom,
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y : -(-tfm.x * tfm.xy + tfm.y * tfm.xx) / denom,
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}
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}
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exports.untransform = function(tfm, pt){
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var xx = pt.x - tfm.x
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var yy = pt.y - tfm.y
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var denom = tfm.xx * tfm.yy - tfm.xy * tfm.yx
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return {
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x : (xx * tfm.yy - yy * tfm.yx) / denom,
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y : (yy * tfm.xx - xx * tfm.xy) / denom,
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onCurve: pt.onCurve,
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cubic: pt.cubic
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}
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} |