Improve BMP generation

backend/Dockerfile

@@ -2,7 +2,7 @@ FROM golang:latest
 
 RUN apt-get update -qq && apt-get install -y netcat
 RUN apt-get install -y -q libsm6 libcups2 libcairo2 libdbus-1-3 libxinerama1
-RUN apt-get install -y texlive-latex-extra poppler-utils
+RUN apt-get install -y texlive-latex-extra texlive-fonts-extra poppler-utils
 
 ## Download pandoc
 

backend/data/screen.tpl.md

@@ -1,10 +1,10 @@
 ---
-fontfamily: libertinus
-fontfamilyoptions:
-- osf
-- p
+fontfamily: dejavu
+#fontfamilyoptions:
+#- osf
+#- p
+#fontsize: 14pt
 papersize: a6
-fontsize: 12pt
 geometry:
 - top=5mm
 - left=5mm

backend/main.go

@@ -53,7 +53,7 @@ var funcmap = template.FuncMap{
 	},
 }
 
-func convertPDFToPNG(filename string) error {
+func convertPDFToBMP(filename string) error {
 	out, err := exec.Command("pdftoppm", filename, "./data/screen", "-png").CombinedOutput()
 	if string(out) != "" {
 		return fmt.Errorf("pdftoppm: %s", string(out))
@@ -61,6 +61,20 @@ func convertPDFToPNG(filename string) error {
 	if err != nil {
 		return err
 	}
+	out, err = exec.Command("convert", "./data/screen-1.png",
+		"-rotate", "-90",
+		"-resize", "800x480!",
+		"-dither", "none",
+		"-remap", "./data/palette.gif",
+		"BMP3:./data/screen.bmp",
+	).CombinedOutput()
+	if string(out) != "" {
+		return fmt.Errorf("covert: %s", string(out))
+	}
+	if err != nil {
+		return err
+	}
+
 	return nil
 }
 
@@ -93,14 +107,14 @@ func serveScreen(res http.ResponseWriter, req *http.Request) {
 		panic(err)
 	}
 
-	log.Println("Converting pdf to png.")
-	err = convertPDFToPNG("./data/screen.pdf")
+	log.Println("Converting PDF to monochrome BMP.")
+	err = convertPDFToBMP("./data/screen.pdf")
 	if err != nil {
 		panic(err)
 	}
 
 	log.Println("Serving screen.png...")
-	http.ServeFile(res, req, "./data/screen-1.png")
+	http.ServeFile(res, req, "./data/screen.bmp")
 }
 
 func main() {