map-dots/imaging/circles.go

79 lines
2.5 KiB
Go

package imaging
import (
"image"
"git.fjla.uk/fred.boniface/map-dots/data"
"git.fjla.uk/fred.boniface/map-dots/log"
"github.com/fogleman/gg"
)
func mapCirclesToCanvas(img *image.RGBA, circles []data.LocationData) {
log.Msg.Debug("Mapping circles to canvas")
dc := gg.NewContextForRGBA(img)
dc.SetRGB(1, 1, 1) // Set canvas background color (white in this case)
circleRadius := 10 // Replace with your desired fixed radius
bounds := img.Bounds()
canvasWidth := bounds.Max.X - bounds.Min.X
canvasHeight := bounds.Max.Y - bounds.Min.Y
var minLat, maxLat, minLon, maxLon float64
for _, circle := range circles {
if circle.Latitude < minLat {
minLat = circle.Latitude
}
if circle.Latitude > maxLat {
maxLat = circle.Latitude
}
if circle.Longitude < minLon {
minLon = circle.Longitude
}
if circle.Longitude > maxLon {
maxLon = circle.Longitude
}
}
for _, circle := range circles {
// Convert latitude and longitude to pixel position on the canvas
pixelX, pixelY := convertCoordinatesToPixels(circle.Latitude, circle.Longitude, minLat, maxLat, minLon, maxLon, canvasWidth, canvasHeight)
// Draw the circle on the canvas using gg
dc.DrawCircle(float64(pixelX), float64(pixelY), float64(circleRadius))
dc.SetRGBA(1, 1, 1, 0.5) // Circle fill color (white with 50% opacity)
dc.Fill()
}
dc.Clip() // Apply clipping
// Optional: Save the canvas as an image file
err := dc.SavePNG("output.png")
if err != nil {
// Handle error
}
}
func convertCoordinatesToPixels(latitude, longitude float64, minLat, maxLat, minLon, maxLon float64, canvasWidth, canvasHeight int) (int, int) {
// Calculate margins as a percentage of canvas dimensions
marginPercentage := 0.1 // 10% margin
marginWidth := int(float64(canvasWidth) * marginPercentage)
marginHeight := int(float64(canvasHeight) * marginPercentage)
// Adjust the bounding box with margins
minLat -= (maxLat - minLat) * marginPercentage
maxLat += (maxLat - minLat) * marginPercentage
minLon -= (maxLon - minLon) * marginPercentage
maxLon += (maxLon - minLon) * marginPercentage
// Calculate the position within the adjusted bounding box
latPercentage := (latitude - minLat) / (maxLat - minLat)
lonPercentage := (longitude - minLon) / (maxLon - minLon)
// Calculate the pixel positions on the canvas
pixelX := int(lonPercentage*float64(canvasWidth-marginWidth*2)) + marginWidth
pixelY := canvasHeight - (int(latPercentage*float64(canvasHeight-marginHeight*2)) + marginHeight)
return pixelX, pixelY
}