display.go

package unicornsignage

import (
	"bytes"
	"embed"
	"image"
	"image/color"
	"strconv"

	owm "github.com/briandowns/openweathermap"
	"github.com/disintegration/imaging"
	"github.com/fogleman/gg"
	"github.com/golang/freetype/truetype"
	"golang.org/x/image/font"
)

func ImageFromText(text string, fontBytes []byte, x int, fontsize int) (outimg image.Image, err error) {
	newImage := image.NewNRGBA(image.Rect(0, 0, 16, 16))
	labelImage, err := addText(newImage, -x, 12, text, fontsize, fontBytes)
	if err != nil {
		return nil, err
	}

	// rotate the image by 90 degrees
	dstImage := imaging.Rotate90(labelImage)
	return dstImage, nil
}

func GetWeatherImageFromAPI(apikey string, location string, imageLocation embed.FS) (outImage image.Image, err error) {
	w, err := owm.NewCurrent("C", "EN", apikey)
	if err != nil {
		return nil, err
	}
	err = w.CurrentByName(location)
	if err != nil {
		return nil, err
	}
	id := w.Weather[0].ID
	isNight := w.Weather[0].Icon[len(w.Weather[0].Icon)-1:] == "n"
	existingImageFile, err := imageLocation.ReadFile("images/" + "weatherImages/" + strconv.Itoa(id) + ".png")
	if err != nil {
		if isNight {
			existingImageFile, err = imageLocation.ReadFile("images/" + "weatherImages/" + strconv.Itoa(id) + "n" + ".png")
			if err != nil {
				return nil, err
			}
		} else {
			existingImageFile, err = imageLocation.ReadFile("images/" + "weatherImages/" + strconv.Itoa(id) + "d" + ".png")
			if err != nil {
				return nil, err
			}
		}
	}
	existingImage, _, err := image.Decode(bytes.NewReader(existingImageFile))
	if err != nil {
		return nil, err
	}
	return existingImage, nil
}

func RotateImage90(img image.Image) (outimage image.Image, err error) {
	// rotate the image by 90 degrees
	dstImage := imaging.Rotate(img, 90, color.Black)
	return dstImage, nil
}

func loadFontFaceReader(fontBytes []byte, points float64) (font.Face, error) {
	f, err := truetype.Parse(fontBytes)
	if err != nil {
		return nil, err
	}
	face := truetype.NewFace(f, &truetype.Options{
		Size: points,
		// Hinting: font.HintingFull,
	})
	return face, nil
}

func addText(img image.Image, x, y int, label string, size int, fontBytes []byte) (outimage image.Image, err error) {
	var w = img.Bounds().Dx()
	var h = img.Bounds().Dy()
	dc := gg.NewContext(w, h)
	// Text color - white
	dc.SetRGB(1, 1, 1)

	face, err := loadFontFaceReader(fontBytes, float64(size))
	if err != nil {
		return nil, err
	}
	dc.SetFontFace(face)

	// Draw the background
	dc.DrawImage(img, 0, 0)
	// Draw text at position - anchor on the top left corner of the text
	dc.DrawStringAnchored(label, float64(x), float64(y), 0, 0)
	dc.Clip()

	outimage = dc.Image()
	return outimage, nil
}