Add annotate-image node

utility/annotate-image/annotate.js

@@ -0,0 +1,155 @@
+module.exports = function(RED) {
+    "use strict";
+    const pureimage = require("pureimage");
+    const Readable = require("stream").Readable;
+    const Writable = require("stream").Writable;
+    const path = require("path");
+
+    let fontLoaded = false;
+    function loadFont() {
+        if (!fontLoaded) {
+            const fnt = pureimage.registerFont(path.join(__dirname,'./SourceSansPro-Regular.ttf'),'Source Sans Pro');
+            fnt.load();
+            fontLoaded = true;
+        }
+    }
+
+    function AnnotateNode(n) {
+        RED.nodes.createNode(this,n);
+        var node = this;
+        const defaultFill = n.fill || "";
+        const defaultStroke = n.stroke || "#ffC000";
+        const defaultLineWidth = parseInt(n.lineWidth) || 5;
+        const defaultFontSize = n.fontSize || 24;
+        const defaultFontColor = n.fontColor || "#ffC000"
+        loadFont();
+
+        this.on("input", function(msg) {
+            if (Buffer.isBuffer(msg.payload)) {
+                if (msg.payload[0] !== 0xFF || msg.payload[1] !== 0xD8) {
+                    node.error("Not a JPEG image",msg);
+                } else if (Array.isArray(msg.annotations) && msg.annotations.length > 0) {
+                    const stream = new Readable();
+                    stream.push(msg.payload);
+                    stream.push(null);
+                    pureimage.decodeJPEGFromStream(stream).then(img => {
+                        const c = pureimage.make(img.width, img.height);
+                        const ctx = c.getContext('2d');
+                        ctx.drawImage(img,0,0,img.width,img.height);
+
+                        ctx.lineJoin = 'bevel';
+
+                        msg.annotations.forEach(function(annotation) {
+                            ctx.fillStyle = annotation.fill || defaultFill;
+                            ctx.strokeStyle = annotation.stroke || defaultStroke;
+                            ctx.lineWidth = annotation.lineWidth || defaultLineWidth;
+                            ctx.lineJoin = 'bevel';
+                            let x,y,r,w,h;
+                            switch(annotation.type) {
+                                case 'rect':
+                                    if (annotation.bbox) {
+                                        x = annotation.bbox[0]
+                                        y = annotation.bbox[1]
+                                        w = annotation.bbox[2]
+                                        h = annotation.bbox[3]
+                                    } else {
+                                        x = annotation.x
+                                        y = annotation.y
+                                        w = annotation.w
+                                        h = annotation.h
+                                    }
+
+                                    if (x < 0) {
+                                        w += x;
+                                        x = 0;
+                                    }
+                                    if (y < 0) {
+                                        h += y;
+                                        y = 0;
+                                    }
+                                    ctx.beginPath();
+                                    ctx.lineWidth = annotation.lineWidth || defaultLineWidth;
+                                    ctx.rect(x,y,w,h);
+                                    ctx.closePath();
+                                    ctx.stroke();
+
+                                    if (annotation.label) {
+                                        ctx.font = `${annotation.fontSize || defaultFontSize}pt 'Source Sans Pro'`;
+                                        ctx.fillStyle = annotation.fontColor || defaultFontColor;
+                                        ctx.textBaseline = "top";
+                                        ctx.textAlign = "left";
+                                        ctx.fillText(annotation.label, x+2,y)
+                                    }
+                                break;
+                                case 'circle':
+                                    if (annotation.bbox) {
+                                        x = annotation.bbox[0] + annotation.bbox[2]/2
+                                        y = annotation.bbox[1] + annotation.bbox[3]/2
+                                        r = Math.min(annotation.bbox[2],annotation.bbox[3])/2;
+                                    } else {
+                                        x = annotation.x
+                                        y = annotation.y
+                                        r = annotation.r;
+                                    }
+                                    ctx.beginPath();
+                                    ctx.lineWidth = annotation.lineWidth || defaultLineWidth;
+                                    ctx.arc(x,y,r,0,Math.PI*2);
+                                    ctx.closePath();
+                                    ctx.stroke();
+                                    if (annotation.label) {
+                                        ctx.font = `${annotation.fontSize || defaultFontSize}pt 'Source Sans Pro'`;
+                                        ctx.fillStyle = annotation.fontColor || defaultFontColor;
+                                        ctx.textBaseline = "middle";
+                                        ctx.textAlign = "center";
+                                        ctx.fillText(annotation.label, x+2,y)
+                                    }
+                                break;
+                            }
+                        });
+                        const bufferOutput = getWritableBuffer();
+                        pureimage.encodeJPEGToStream(c,bufferOutput.stream,90).then(() => {
+                            msg.payload = bufferOutput.getBuffer();
+                            node.send(msg);
+                        })
+                    }).catch(err => {
+                        node.error(err,msg);
+                    })
+                } else {
+                    // No annotations to make - send the message on
+                    node.send(msg);
+                }
+            } else {
+                node.error("Payload not a Buffer",msg)
+            }
+            return msg;
+        });
+    }
+    RED.nodes.registerType("annotate-image",AnnotateNode);
+
+
+
+    function getWritableBuffer() {
+        var currentSize = 0;
+        var buffer = null;
+        const stream = new Writable({
+            write(chunk, encoding, callback) {
+                if (!buffer) {
+                    buffer = Buffer.from(chunk);
+                } else {
+                    var newBuffer = Buffer.allocUnsafe(currentSize + chunk.length);
+                    buffer.copy(newBuffer);
+                    chunk.copy(newBuffer,currentSize);
+                    buffer = newBuffer;
+                }
+                currentSize += chunk.length
+                callback();
+            }
+        });
+        return {
+            stream:  stream,
+            getBuffer: function() {
+                return buffer;
+            }
+        }
+    }
+}