69 lines
1.3 KiB
Go
69 lines
1.3 KiB
Go
package drawing
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import (
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"math"
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"golang.org/x/image/math/fixed"
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"github.com/golang/freetype/raster"
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"github.com/golang/freetype/truetype"
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)
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// PixelsToPoints returns the points for a given number of pixels at a DPI.
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func PixelsToPoints(dpi, pixels float64) (points float64) {
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points = (pixels * 72.0) / dpi
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return
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}
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// PointsToPixels returns the pixels for a given number of points at a DPI.
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func PointsToPixels(dpi, points float64) (pixels float64) {
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pixels = (points * dpi) / 72.0
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return
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}
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func abs(i int) int {
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if i < 0 {
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return -i
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}
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return i
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}
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func distance(x1, y1, x2, y2 float64) float64 {
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return vectorDistance(x2-x1, y2-y1)
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}
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func vectorDistance(dx, dy float64) float64 {
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return float64(math.Sqrt(dx*dx + dy*dy))
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}
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func toFtCap(c LineCap) raster.Capper {
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switch c {
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case RoundCap:
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return raster.RoundCapper
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case ButtCap:
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return raster.ButtCapper
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case SquareCap:
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return raster.SquareCapper
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}
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return raster.RoundCapper
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}
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func toFtJoin(j LineJoin) raster.Joiner {
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switch j {
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case RoundJoin:
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return raster.RoundJoiner
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case BevelJoin:
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return raster.BevelJoiner
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}
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return raster.RoundJoiner
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}
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func pointToF64Point(p truetype.Point) (x, y float64) {
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return fUnitsToFloat64(p.X), -fUnitsToFloat64(p.Y)
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}
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func fUnitsToFloat64(x fixed.Int26_6) float64 {
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scaled := x << 2
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return float64(scaled/256) + float64(scaled%256)/256.0
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}
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