From 017762c462dc8771449aa765cf67efcfde0e4c3b Mon Sep 17 00:00:00 2001
From: Neil Gershenfeld <gersh@cba.mit.edu>
Date: Mon, 27 Sep 2021 08:56:42 -0400
Subject: [PATCH] start line scanner
---
modules/input/video | 51 ++++++++++-
modules/processes/scan/line | 164 ++++++++++++++++++++++++++++++++++++
2 files changed, 213 insertions(+), 2 deletions(-)
create mode 100644 modules/processes/scan/line
diff --git a/modules/input/video b/modules/input/video
index 1faea25..14fe38c 100644
--- a/modules/input/video
+++ b/modules/input/video
@@ -28,7 +28,7 @@ var init = function() {
mod.width.value = 640
mod.height.value = 480
mod.flip.checked = false
- start_video()
+ list_video()
}
//
// inputs
@@ -67,6 +67,25 @@ var interface = function(div){
var canvas = document.createElement('canvas')
mod.img = canvas
//
+ // camera select
+ //
+ var select = document.createElement('select')
+ div.appendChild(select)
+ mod.select = select
+ div.appendChild(document.createElement('br'))
+ //
+ // start button
+ //
+ var btn = document.createElement('button')
+ btn.style.padding = mods.ui.padding
+ btn.style.margin = 1
+ btn.appendChild(document.createTextNode('start'))
+ btn.addEventListener('click',function() {
+ start_video()
+ })
+ div.appendChild(btn)
+ div.appendChild(document.createTextNode(' '))
+ //
// capture button
//
var btn = document.createElement('button')
@@ -149,6 +168,24 @@ var interface = function(div){
//
// local functions
//
+// add cameras to list
+//
+function list_video() {
+ navigator.mediaDevices.enumerateDevices()
+ .then(function(devices) {
+ devices.forEach(function(device) {
+ if (device.kind == 'videoinput') {
+ var el = document.createElement('option')
+ el.textContent = device.label
+ el.value = device.deviceId
+ mod.select.appendChild(el)
+ }
+ })
+ })
+ }
+//
+// start video
+//
function start_video() {
var w = parseInt(mod.width.value)
var h = parseInt(mod.height.value)
@@ -157,19 +194,26 @@ function start_video() {
ctx.canvas.height = h
var constraints = {
audio:false,
- video:{width:w,height:h}
+ video:{
+ width:w,height:h,
+ deviceId:{exact:mod.select.options[mod.select.selectedIndex].value}
+ }
}
navigator.mediaDevices.getUserMedia(constraints)
.then(function(stream) {
mod.video.srcObject = stream
mod.video.onloadedmetadata = function(e) {
mod.video.play()
+ capture_video()
}
})
.catch(function(err) {
console.log(err.name+': '+err.message)
})
}
+//
+// update video
+//
function update_video() {
var w = parseInt(mod.width.value)
var h = parseInt(mod.height.value)
@@ -179,6 +223,9 @@ function update_video() {
ctx.canvas.width = w
ctx.canvas.height = h
}
+//
+// capture video
+//
function capture_video() {
var w = parseInt(mod.width.value)
var h = parseInt(mod.height.value)
diff --git a/modules/processes/scan/line b/modules/processes/scan/line
new file mode 100644
index 0000000..54f823b
--- /dev/null
+++ b/modules/processes/scan/line
@@ -0,0 +1,164 @@
+//
+// line scan
+//
+// (c) MIT CBA Neil Gershenfeld 9/26/21
+//
+// This work may be reproduced, modified, distributed, performed, and
+// displayed for any purpose, but must acknowledge the fab modules
+// project. Copyright is retained and must be preserved. The work is
+// provided as is; no warranty is provided, and users accept all
+// liability.
+//
+// closure
+//
+(function(){
+//
+// module globals
+//
+var mod = {}
+//
+// name
+//
+var name = 'line scan'
+//
+// initialization
+//
+var init = function() {
+ mod.width.value = 10
+ //
+ // open scan window
+ //
+ var win = window.open('')
+ win.document.title = "scan window"
+ win.document.body.appendChild(document.createElement('br'))
+ var canvas = document.createElement('canvas')
+ win.document.body.appendChild(canvas)
+ mod.scan = canvas
+ mod.win = win
+ }
+//
+// inputs
+//
+var inputs = {
+ image:{type:'RGBA',
+ event:function(evt) {
+ scanloop(evt.detail)
+ }
+ }
+ }
+//
+// outputs
+//
+var outputs = {
+ trigger:{type:'event',
+ event:function(){
+ mods.output(mod,'trigger',null)
+ }
+ }
+ }
+//
+// interface
+//
+var interface = function(div){
+ mod.div = div
+ //
+ // on-screen drawing canvas
+ //
+ var canvas = document.createElement('canvas')
+ canvas.width = mods.ui.canvas
+ canvas.height = mods.ui.canvas
+ canvas.style.backgroundColor = 'rgb(255,255,255)'
+ div.appendChild(canvas)
+ mod.img = canvas
+ div.appendChild(document.createElement('br'))
+ //
+ // line width
+ //
+ div.appendChild(document.createTextNode('scan line width (pixels): '))
+ var input = document.createElement('input')
+ input.type = 'text'
+ input.size = 6
+ input.addEventListener('change',function(){
+ alert('width')
+ })
+ div.appendChild(input)
+ mod.width = input
+ //
+ // start scan button
+ //
+ div.appendChild(document.createElement('br'))
+ div.appendChild(document.createTextNode(' '))
+ var btn = document.createElement('button')
+ btn.style.padding = mods.ui.padding
+ btn.style.margin = 1
+ btn.appendChild(document.createTextNode('start scan'))
+ btn.addEventListener('click',function(){
+ linescan()
+ })
+ div.appendChild(btn)
+ }
+//
+// local functions
+//
+// line scan
+//
+function linescan() {
+ mod.l = parseFloat(mod.width.value)
+ mod.w = mod.win.innerWidth
+ mod.h = mod.win.innerHeight
+ mod.scan.width = mod.w
+ mod.scan.height = mod.h
+ mod.y = 0
+ mod.state = 'start'
+ scanloop(null)
+ }
+//
+// scan loop
+//
+function scanloop(input) {
+ if (mod.state == 'start') {
+ //
+ // take background
+ //
+ var ctx = mod.scan.getContext("2d")
+ ctx.fillStyle = "black"
+ ctx.fillRect(0,0,mod.w,mod.h)
+ mod.state = 'background'
+ outputs.trigger.event()
+ }
+ else if (mod.state == 'background') {
+ //
+ // save background, start scan
+ //
+ mod.state = 'scan'
+ outputs.trigger.event()
+ }
+ else if (mod.state == 'scan') {
+ //
+ // scan
+ //
+ mod.y += mod.l
+ var ctx = mod.scan.getContext("2d")
+ ctx.lineWidth = mod.l
+ ctx.fillStyle = "black"
+ ctx.fillRect(0,0,mod.w,mod.h)
+ ctx.strokeStyle = "white"
+ ctx.beginPath()
+ ctx.moveTo(0,mod.y)
+ ctx.lineTo(mod.w,mod.y)
+ ctx.stroke()
+ if (mod.y < mod.h)
+ outputs.trigger.event()
+ }
+ }
+//
+// return values
+//
+return ({
+ name:name,
+ init:init,
+ inputs:inputs,
+ outputs:outputs,
+ interface:interface
+ })
+}())
--
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