34 lines
829 B
Go
34 lines
829 B
Go
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package artist
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import "math"
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import "image/color"
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// EllipticallyBordered is a pattern with a border and a fill that is elliptical
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// in shape.
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type EllipticallyBordered struct {
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Fill Pattern
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Stroke
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}
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// AtWhen satisfies the Pattern interface.
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func (pattern EllipticallyBordered) AtWhen (x, y, width, height int) (c color.RGBA) {
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xf := (float64(x) + 0.5) / float64(width ) * 2 - 1
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yf := (float64(y) + 0.5) / float64(height) * 2 - 1
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distance := math.Sqrt(xf * xf + yf * yf)
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var radius float64
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if width < height {
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// vertical
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radius = 1 - float64(pattern.Weight * 2) / float64(width)
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} else {
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// horizontal
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radius = 1 - float64(pattern.Weight * 2) / float64(height)
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}
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if distance < radius {
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return pattern.Fill.AtWhen(x, y, width, height)
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} else {
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return pattern.Stroke.AtWhen(x, y, width, height)
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}
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}
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