package label import ( "image" "image/color" "image/draw" "strings" "janouch.name/sklad/bdf" "janouch.name/sklad/imgutil" "github.com/boombuler/barcode" "github.com/boombuler/barcode/qr" ) // TODO: Rename to GenQRLabelForHeight. func GenLabelForHeight(font *bdf.Font, text string, height, scale int) image.Image { // Create a scaled bitmap of the text label. textRect, _ := font.BoundString(text) textImg := image.NewRGBA(textRect) draw.Draw(textImg, textRect, image.White, image.ZP, draw.Src) font.DrawString(textImg, image.ZP, color.Black, text) scaledTextImg := imgutil.Scale{Image: textImg, Scale: scale} scaledTextRect := scaledTextImg.Bounds() remains := height - scaledTextRect.Dy() - 20 width := scaledTextRect.Dx() if remains > width { width = remains } // Create a scaled bitmap of the QR code. qrImg, _ := qr.Encode(text, qr.H, qr.Auto) qrImg, _ = barcode.Scale(qrImg, remains, remains) qrRect := qrImg.Bounds() // Combine. combinedRect := image.Rect(0, 0, width, height) combinedImg := image.NewRGBA(combinedRect) draw.Draw(combinedImg, combinedRect, image.White, image.ZP, draw.Src) draw.Draw(combinedImg, combinedRect.Add(image.Point{X: (width - qrRect.Dx()) / 2, Y: 0}), qrImg, image.ZP, draw.Src) target := image.Rect( (width-scaledTextRect.Dx())/2, qrRect.Dy()+20, combinedRect.Max.X, combinedRect.Max.Y) draw.Draw(combinedImg, target, &scaledTextImg, scaledTextRect.Min, draw.Src) return combinedImg } func max(a, b int) int { if a > b { return a } return b } func GenLabelForWidth(font *bdf.Font, text string, width, scale int) image.Image { var lines []string for _, line := range strings.Split(text, "\n") { lines = append(lines, strings.TrimSuffix(line, "\r")) } // Respect font ascent and descent so that there are gaps between lines. rects := make([]image.Rectangle, len(lines)) jumps := make([]int, len(lines)) for i, line := range lines { r, _ := font.BoundString(line) rects[i] = r if i > 0 { deficitD := font.Descent - rects[i-1].Max.Y jumps[i] += max(0, deficitD) deficitA := font.Ascent - (-r.Min.Y) jumps[i] += max(0, deficitA) } } height := 0 for i := range lines { height += jumps[i] + rects[i].Dy() } imgRect := image.Rect(0, 0, width, height*scale) img := image.NewRGBA(imgRect) draw.Draw(img, imgRect, image.White, image.ZP, draw.Src) y := 0 for i, line := range lines { textImg := image.NewRGBA(rects[i]) draw.Draw(textImg, rects[i], image.White, image.ZP, draw.Src) font.DrawString(textImg, image.ZP, color.Black, line) scaledImg := imgutil.Scale{Image: textImg, Scale: scale} scaledRect := scaledImg.Bounds() y += jumps[i] target := image.Rect(0, y*scale, imgRect.Max.X, imgRect.Max.Y) draw.Draw(img, target, &scaledImg, scaledRect.Min, draw.Src) y += rects[i].Dy() } return img }