128 lines
2.9 KiB
Go
128 lines
2.9 KiB
Go
/*
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* Copyright © 2021 A Bunch Tell LLC.
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*
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* This file is part of text-pic.
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*
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* text-pic is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License, included
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* in the LICENSE file in this source code package.
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*/
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package textpic
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import (
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"fmt"
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"image/color"
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"path/filepath"
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"github.com/fogleman/gg"
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)
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func loadFont(dc *gg.Context, bold bool, points float64) error {
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fontLoraBoldPath := filepath.Join("fonts", "Lora-Bold.ttf")
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fontLoraPath := filepath.Join("fonts", "Lora-Regular.ttf")
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path := fontLoraPath
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if bold {
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path = fontLoraBoldPath
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}
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err := dc.LoadFontFace(path, points)
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if err != nil {
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return fmt.Errorf("load bold font: %s", err)
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}
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return nil
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}
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func GenerateImage(opt *ContentOptions, outputFilename string) error {
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w := 900
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h := 900
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wf := float64(w)
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hf := float64(h)
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dc := gg.NewContext(w, h)
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dc.DrawRectangle(0, 0, wf, hf)
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dc.SetRGB(1, 1, 1)
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dc.Fill()
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// Define margins for footer text
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footerFontSize := 32.0
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footerMargin := 20.0
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x := footerMargin
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y := footerMargin
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footerMarginY := 20.0
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// Content parameters
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contentFontSize := 48.0
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lineSpacing := 1.8
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contentBottomMargin := 100.0
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contentRightMargin := 50.0
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contentTopMargin := 50.0
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contentWidth := wf - contentRightMargin - contentRightMargin
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// Create bold instance name
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err := loadFont(dc, true, footerFontSize)
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if err != nil {
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return err
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}
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instance := opt.Instance
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baseTextWidth, textHeight := dc.MeasureString(instance)
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// Create user path
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err = loadFont(dc, false, footerFontSize)
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if err != nil {
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return err
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}
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dc.SetColor(color.Black)
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userPath := "/" + opt.Username
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userTextWidth, _ := dc.MeasureString(userPath)
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// x = canvas halfway point - total text width halfway point
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x = wf/2 - (baseTextWidth+userTextWidth)/2
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y = hf - textHeight - footerMarginY
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err = loadFont(dc, true, footerFontSize)
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if err != nil {
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return err
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}
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dc.DrawString(instance, x, y)
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// x = original x coordinate + base text width
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x += baseTextWidth
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y = hf - textHeight - footerMarginY
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err = loadFont(dc, false, footerFontSize)
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if err != nil {
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return err
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}
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dc.DrawString(userPath, x, y)
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// Draw the content
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err = loadFont(dc, false, contentFontSize)
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if err != nil {
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return err
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}
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s := opt.Content
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lines := dc.WordWrap(s, contentWidth)
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// Center-align text by default for short content
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alignment := gg.AlignCenter
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linesStr := ""
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for i, str := range lines {
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linesStr += str
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if i != len(lines)-1 {
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linesStr += "\n"
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if alignment == gg.AlignCenter {
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// Since content uses multiple lines, left-align it.
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alignment = gg.AlignLeft
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}
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}
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}
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_, contentTextHeight := dc.MeasureMultilineString(linesStr, lineSpacing)
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x = contentRightMargin
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y = contentTopMargin - contentBottomMargin + hf/2 - contentTextHeight/2
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dc.DrawStringWrapped(s, x, y, 0, 0, contentWidth, lineSpacing, alignment)
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err = dc.SavePNG(outputFilename)
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if err != nil {
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return fmt.Errorf("save png: %s", err)
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}
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return nil
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}
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