LLKennedy/imagetemplate

// Package barcode is a component for rendering barcodes with customisable content and colour for both background and data channels.
package barcode

import (
    "fmt"
    "image"
    "image/color"

    "github.com/LLKennedy/imagetemplate/v3/render"
    "golang.org/x/tools/godoc/vfs"
)

// Component implements the Component interface for images.
type Component struct {
    /*
        NamedPropertiesMap maps user/application variables to properties of the component.
        This field is filled automatically by VerifyAndSetJSONData, then used in
        SetNamedProperties to determine whether a variable being passed in is relevant to this
        component.

        For example, map[string][]string{"websiteURL": []string{"content"}} would indicate that
        the user specified variable "websiteURL" will fill the Content property.
    */
    NamedPropertiesMap map[string][]string
    // Content is the data which will be encoded as a barcode.
    Content string
    // Type is the sort of barcode to encode, such as QR, PDF, or two of five.
    Type render.BarcodeType
    /*
        TopLeft is the coordinates of the top-left corner of the rendered barcode (including
        background) relative to the top-left corner of the canvas.
    */
    TopLeft image.Point
    // Width is the width of the barcode (including background).
    Width int
    // Height is the height of the barcode (including background).
    Height int
    // DataColour is the colour which will fill the data channel.
    DataColour color.NRGBA
    // BackgroundColour is the colour which will fill the background channel.
    BackgroundColour color.NRGBA
    // Extra is additional information required by certain barcode types.
    Extra render.BarcodeExtraData
}

type barcodeFormat struct {
    Content    string `json:"content"`
    Type       string `json:"barcodeType"`
    TopLeftX   string `json:"topLeftX"`
    TopLeftY   string `json:"topLeftY"`
    Width      string `json:"width"`
    Height     string `json:"height"`
    DataColour struct {
        Red   string `json:"R"`
        Green string `json:"G"`
        Blue  string `json:"B"`
        Alpha string `json:"A"`
    } `json:"dataColour"`
    BackgroundColour struct {
        Red   string `json:"R"`
        Green string `json:"G"`
        Blue  string `json:"B"`
        Alpha string `json:"A"`
    } `json:"backgroundColour"`
}

// Write draws a barcode on the canvas.
func (component Component) Write(canvas render.Canvas) (render.Canvas, error) {
    if len(component.NamedPropertiesMap) != 0 {
        return canvas, fmt.Errorf("cannot draw barcode, not all named properties are set: %v", component.NamedPropertiesMap)
    }
    c := canvas
    var err error
    c, err = c.Barcode(component.Type, []byte(component.Content), component.Extra, component.TopLeft, component.Width, component.Height, component.DataColour, component.BackgroundColour)
    if err != nil {
        return canvas, err
    }
    return c, nil
}

// SetNamedProperties processes the named properties and sets them into the barcode properties.
func (component Component) SetNamedProperties(properties render.NamedProperties) (render.Component, error) {
    c := component
    var err error
    c.NamedPropertiesMap, err = render.StandardSetNamedProperties(properties, component.NamedPropertiesMap, (&c).delegatedSetProperties)
    if err != nil {
        return component, err
    }
    return c, nil
}

// GetJSONFormat returns the JSON structure of a barcode component.
func (component Component) GetJSONFormat() interface{} {
    return &barcodeFormat{}
}

// VerifyAndSetJSONData processes the data parsed from JSON and uses it to set barcode properties and fill the named properties map.
func (component Component) VerifyAndSetJSONData(data interface{}) (render.Component, render.NamedProperties, error) {
    c := component
    props := make(render.NamedProperties)
    stringStruct, ok := data.(*barcodeFormat)
    if !ok {
        return component, props, fmt.Errorf("failed to convert returned data to component properties")
    }
    return c.parseJSONFormat(stringStruct, props)
}

func init() {
    for _, name := range []string{"barcode", "bar", "code", "Barcode", "BARCODE", "BAR", "Bar Code", "bar code"} {
        render.RegisterComponent(name, func(vfs.FileSystem) render.Component { return Component{} })
    }
}