clessy/mods/memegen.go

package main

import (
	"bytes"
	"encoding/base64"
	"image"
	_ "image/gif"
	"image/jpeg"
	_ "image/png"
	"io/ioutil"
	"log"
	"os"
	"strings"

	"github.com/golang/freetype"
	"github.com/hamcha/clessy/tg"
	"github.com/llgcode/draw2d"
	"github.com/llgcode/draw2d/draw2dimg"
)

var memeFontData draw2d.FontData

func initmeme() {
	fontfile, err := os.Open(*impact)
	assert(err)
	defer fontfile.Close()

	bytes, err := ioutil.ReadAll(fontfile)
	assert(err)

	font, err := freetype.ParseFont(bytes)
	assert(err)

	memeFontData := draw2d.FontData{"impact", draw2d.FontFamilySans, 0}
	draw2d.RegisterFont(memeFontData, font)
}

func memegen(broker *tg.Broker, update tg.APIMessage) {
	if update.Photo != nil && update.Caption != nil {
		caption := *(update.Caption)
		if strings.HasPrefix(caption, "/meme ") && len(caption) > 6 {
			idx := strings.Index(caption, ";")
			if idx < 0 {
				broker.SendTextMessage(update.Chat, "<b>Formato</b>: /meme TESTO IN ALTO<b>;</b>TESTO IN BASSO", &update.MessageID)
				return
			}

			txtup := caption[6:idx]
			txtdw := caption[idx+1:]

			maxsz := 0
			photo := tg.APIPhotoSize{}
			for _, curphoto := range update.Photo {
				if curphoto.Width > maxsz {
					maxsz = curphoto.Width
					photo = curphoto
				}
			}
			broker.GetFile(photo.FileID, func(broker *tg.Broker, data tg.BrokerUpdate) {
				pbytes, err := base64.StdEncoding.DecodeString(*data.Bytes)
				if err != nil {
					log.Println("[memegen] Base64 decode error: %s\n", err.Error())
					broker.SendTextMessage(update.Chat, "<b>ERRORE!</b> @hamcha controlla la console!", &update.MessageID)
					return
				}

				img, _, err := image.Decode(bytes.NewReader(pbytes))
				if err != nil {
					log.Println("[memegen] Image decode error: %s\n", err.Error())
					broker.SendTextMessage(update.Chat, "<b>ERROR</b>: Non riesco a leggere l'immagine", &update.MessageID)
					return
				}

				//TODO Clean up this mess

				// Create target image
				bounds := img.Bounds()
				iwidth := float64(bounds.Size().X)
				iheight := float64(bounds.Size().Y)

				timg := image.NewRGBA(bounds)
				gc := draw2dimg.NewGraphicContext(timg)
				gc.SetStrokeColor(image.Black)
				gc.SetFillColor(image.White)
				gc.SetFontData(memeFontData)
				gc.DrawImage(img)

				write := func(text string, istop bool) {
					text = strings.ToUpper(strings.TrimSpace(text))
					gc.Restore()
					gc.Save()

					// Detect appropriate font size
					scale := iwidth / iheight * 200
					gc.SetFontSize(scale)
					gc.SetLineWidth(scale / 15)

					// Get NEW bounds
					left, top, right, bottom := gc.GetStringBounds(text)

					width := right - left
					texts := []string{text}
					if width > iwidth {
						// Split text
						texts = splitCenter(text)

						// Get longest line
						longer := float64(0)
						longid := 0
						widths := make([]float64, len(texts))
						for id := range texts {
							tleft, _, tright, _ := gc.GetStringBounds(texts[id])
							widths[id] = tright - tleft
							if width > longer {
								longer = widths[id]
								longid = id
							}
						}

						// Still too big? Decrease font size again
						iter := 0
						for width > iwidth && iter < 10 {
							left, _, right, _ = gc.GetStringBounds(texts[longid])
							gc.SetFontSize(scale * 0.8)
							width = right - left
							iter++
						}
					}

					height := bottom - top
					margin := float64(10)
					lines := float64(len(texts) - 1)

					gc.Save()
					for id, txt := range texts {
						gc.Save()
						left, _, right, _ = gc.GetStringBounds(txt)
						width = right - left

						y := float64(0)
						if istop {
							y = (height-margin)*float64(id+1) + margin*5
						} else {
							y = iheight - (height * lines) + (height * float64(id)) - margin*5
						}

						gc.Translate((iwidth-width)/2, y)
						gc.StrokeString(txt)
						gc.FillString(txt)
						gc.Restore()
					}
				}
				write(txtup, true)
				write(txtdw, false)

				buf := new(bytes.Buffer)
				err = jpeg.Encode(buf, timg, &(jpeg.Options{Quality: 80}))
				if err != nil {
					log.Println("[memegen] Image encode error: %s\n", err.Error())
					broker.SendTextMessage(update.Chat, "<b>ERRORE!</b> @hamcha controlla la console!", &update.MessageID)
					return
				}
			})
		}
	}
}

func splitCenter(text string) []string {
	cindx := int(len(text) / 2)
	bs := 0
	md := 9999
	id := -1
	for i := 0; ; i++ {
		idx := strings.Index(text[bs:], " ")
		if idx < 0 {
			break
		}
		bs += idx + 1
		diff := abs(cindx - bs)
		if diff < md {
			md = diff
			id = bs - 1
		}
	}
	if id >= 0 {
		return []string{text[0:id], text[id+1:]}
	}
	return []string{text}
}

func abs(i int) int {
	if i < 0 {
		return -i
	}
	return i
}