83 lines
2.4 KiB
Go
83 lines
2.4 KiB
Go
package imaging
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import (
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"fmt"
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"image"
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"math"
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"git.fjla.uk/fred.boniface/map-dots/data"
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"git.fjla.uk/fred.boniface/map-dots/log"
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"github.com/fogleman/gg"
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)
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func mapCirclesToCanvas(img *image.RGBA, locations []data.LocationData) {
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log.Msg.Debug("Mapping locations to canvas")
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dc := gg.NewContextForRGBA(img)
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dc.SetRGB(1, 1, 1) // Set canvas background color (white in this case)
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circleRadius := 4 // Replace with your desired fixed radius
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bounds := img.Bounds()
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canvasWidth := bounds.Max.X - bounds.Min.X
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canvasHeight := bounds.Max.Y - bounds.Min.Y
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var minLat, maxLat, minLon, maxLon float64
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for _, loc := range locations {
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if loc.Latitude < minLat {
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minLat = loc.Latitude
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}
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if loc.Latitude > maxLat {
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maxLat = loc.Latitude
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}
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if loc.Longitude < minLon {
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minLon = loc.Longitude
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}
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if loc.Longitude > maxLon {
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maxLon = loc.Longitude
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}
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}
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centerLat := (maxLat + minLat) / 2.0
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centerLon := (maxLon + minLon) / 2.0
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latRange := maxLat - minLat
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lonRange := maxLon - minLon
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for _, loc := range locations {
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pixelX, pixelY := convertCoordinatesToPixels(loc.Latitude, loc.Longitude, centerLat, centerLon, latRange, lonRange, canvasWidth, canvasHeight)
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// Draw the circle on the canvas using gg
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dc.DrawCircle(float64(pixelX), float64(pixelY), float64(circleRadius))
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dc.SetRGBA(1, 1, 1, 0.5) // Circle fill color (white with 50% opacity)
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dc.Fill()
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}
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dc.Clip() // Apply clipping
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// Optional: Save the canvas as an image file
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err := dc.SavePNG("output.png")
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if err != nil {
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log.Msg.Error("Error saving file")
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} else {
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fmt.Println("Canvas saves to file")
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}
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}
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func convertCoordinatesToPixels(latitude, longitude float64, centerLat, centerLon, latRange, lonRange float64, canvasWidth, canvasHeight int) (int, int) {
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// Calculate normalized latitude and longitude distances from the center
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latDist := (latitude - centerLat) / (latRange * 0.5)
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lonDist := (longitude - centerLon) / (lonRange * 0.5)
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// Calculate the maximum distance from the center as a proportion of canvas size
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maxDistance := math.Max(math.Abs(latDist), math.Abs(lonDist))
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// Adjust the normalized distances to match the canvas size with margins
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adjustedLatDist := latDist / maxDistance * 0.45
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adjustedLonDist := lonDist / maxDistance * 0.45
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// Calculate pixel positions
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pixelX := int((adjustedLonDist + 0.5) * float64(canvasWidth))
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pixelY := int((0.5 - adjustedLatDist) * float64(canvasHeight))
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return pixelX, pixelY
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}
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