Adding background support for non-svgs

go.mod

@@ -3,7 +3,7 @@ module github.com/kenshaw/iv
 go 1.20
 
 require (
-	github.com/kenshaw/colors v0.1.2
+	github.com/kenshaw/colors v0.1.4
 	github.com/kenshaw/rasterm v0.1.10
 	github.com/spf13/cobra v1.8.0
 	github.com/xo/resvg v0.4.0

go.sum

@@ -1,8 +1,8 @@
 github.com/cpuguy83/go-md2man/v2 v2.0.3/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
-github.com/kenshaw/colors v0.1.2 h1:qy1V9XzxSbUkFW3WyeTf3+ma3604Qks/S9iWDi3cyqE=
-github.com/kenshaw/colors v0.1.2/go.mod h1:m8LcSiaLgIxtzCHQqxReKkJPP5TfXUZZdQvFdCuQGyY=
+github.com/kenshaw/colors v0.1.4 h1:2IbZLfJJlLuUyHN6/vgMK+1b4g+9GcD6u2pBx9GwviE=
+github.com/kenshaw/colors v0.1.4/go.mod h1:m8LcSiaLgIxtzCHQqxReKkJPP5TfXUZZdQvFdCuQGyY=
 github.com/kenshaw/rasterm v0.1.10 h1:cMCTpBHfqmftt/VqeT6B+9Td+mYi+ZtziN+XBdrTQfA=
 github.com/kenshaw/rasterm v0.1.10/go.mod h1:kL4DCN+wOlQ4BPBCxA+itiVwiObRAj0Hkze7SbCyYaw=
 github.com/kenshaw/snaker v0.2.0 h1:DPlxCtAv9mw1wSsvIN1khUAPJUIbFJUckMIDWSQ7TC8=

main.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"image"
 	"image/color"
+	"image/draw"
 	"io"
 	"os"
 	"path/filepath"
@@ -111,7 +112,7 @@ func do(w io.Writer, bg color.Color, args []string) error {
 		}
 		files = append(files, v...)
 	}
-	return render(w, files)
+	return render(w, bg, files)
 }
 
 func open(name string) ([]string, error) {
@@ -138,36 +139,49 @@ func open(name string) ([]string, error) {
 
 var extRE = regexp.MustCompile(`(?i)\.(jpe?g|gif|png|svg|bmp|bitmap|tiff?|hei[vc]|webp)$`)
 
-func render(w io.Writer, files []string) error {
+func render(w io.Writer, bg color.Color, files []string) error {
+	var c color.Color
+	if !colors.Is(bg, colors.Transparent) {
+		c = color.NRGBAModel.Convert(bg).(color.NRGBA)
+	}
 	for i := 0; i < len(files); i++ {
-		if err := renderFile(w, files[i]); err != nil {
+		if err := renderFile(w, c, files[i]); err != nil {
 			fmt.Fprintf(w, "error: unable to render arg %d: %v\n", i, err)
 		}
 	}
 	return nil
 }
 
 // doFile renders the specified file to w.
-func renderFile(w io.Writer, file string) error {
+func renderFile(w io.Writer, bg color.Color, file string) error {
 	fmt.Fprintln(w, file+":")
 	f, err := os.OpenFile(file, os.O_RDONLY, 0)
 	if err != nil {
 		return fmt.Errorf("can't open %s: %w", file, err)
 	}
-	img, _, err := image.Decode(f)
+	img, typ, err := image.Decode(f)
 	if err != nil {
 		defer f.Close()
 		return fmt.Errorf("can't decode %s: %w", file, err)
 	}
 	if err := f.Close(); err != nil {
 		return fmt.Errorf("can't close %s: %w", file, err)
 	}
+	if typ != "svg" && bg != nil {
+		img = addBackground(bg.(color.NRGBA), img)
+	}
 	return rasterm.Encode(w, img)
 }
 
-/*
-func init() {
-	_ "github.com/jcbritobr/pnm"
-	image.RegisterFormat("pbm", "P?", Decode, DecodeConfig)
+// addBackground adds a background for the image.
+func addBackground(bg color.NRGBA, fg image.Image) image.Image {
+	b := fg.Bounds()
+	img := image.NewNRGBA(b)
+	for i := 0; i < b.Dx(); i++ {
+		for j := 0; j < b.Dy(); j++ {
+			img.SetNRGBA(i, j, bg)
+		}
+	}
+	draw.Draw(img, b, fg, image.Point{}, draw.Over)
+	return img
 }
-*/