horizontal flip for double sided boards

modules/read/png

@@ -5,7 +5,7 @@
 // (c) Massachusetts Institute of Technology 2015,6
 // 
 // This work may be reproduced, modified, distributed, performed, and 
-// displayed for any purpose, but must acknowledge the mods
+// 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.
@@ -139,6 +139,18 @@ var interface = function(div){
       div.appendChild(btn)
    div.appendChild(document.createElement('br'))
    //
+   // flip button
+   //
+   var flip_btn = document.createElement('button')
+      flip_btn.style.padding = mods.ui.padding
+      flip_btn.style.margin = 1
+      flip_btn.appendChild(document.createTextNode('flip'))
+      flip_btn.addEventListener('click',function(){
+         flip_image()
+         })
+      div.appendChild(flip_btn)
+   div.appendChild(document.createElement('br'))
+   //
    // info div
    //
    var info = document.createElement('div')
@@ -334,10 +346,83 @@ function worker() {
       })
    }
 //
+// flip image
+//
+function flip_image() {
+   var blob = new Blob(['('+flip_worker.toString()+'())'])
+   var url = window.URL.createObjectURL(blob)
+   var webworker = new Worker(url)
+   webworker.addEventListener('message',function(evt) {
+      window.URL.revokeObjectURL(url)
+      var h = mod.img.height
+      var w = mod.img.width
+      var buf = new Uint8ClampedArray(evt.data.buffer)
+      var imgdata = new ImageData(buf,w,h)
+      var ctx = mod.img.getContext("2d")
+      ctx.putImageData(imgdata,0,0)
+      if (w > h) {
+         var x0 = 0
+         var y0 = mod.canvas.height*.5*(1-h/w)
+         var wd = mod.canvas.width
+         var hd = mod.canvas.width*h/w
+         }
+      else {
+         var x0 = mod.canvas.width*.5*(1-w/h)
+         var y0 = 0
+         var wd = mod.canvas.height*w/h
+         var hd = mod.canvas.height
+         }
+      var ctx = mod.canvas.getContext("2d")
+      ctx.drawImage(mod.img,x0,y0,wd,hd)
+      webworker.terminate()
+      outputs.image.event()
+      })
+   var ctx = mod.canvas.getContext("2d")
+   ctx.clearRect(0,0,mod.canvas.width,mod.canvas.height)
+   var h = mod.img.height
+   var w = mod.img.width
+   var ctx = mod.img.getContext("2d")
+   var img = ctx.getImageData(0,0,w,h)
+   webworker.postMessage({
+      height:img.height,width:img.width,buffer:img.data.buffer},
+      [img.data.buffer])
+   }
+function flip_worker() {
+   self.addEventListener('message',function(evt) {
+      var h = evt.data.height
+      var w = evt.data.width
+      var buf = new Uint8ClampedArray(evt.data.buffer)
+      var index = 0
+      for (var row = 0; row < h; ++row) {
+         for (var col = 0; col < w/2; ++col) {
+            index = (h-1-row)*w*4+col*4
+            r_index = (h-1-row)*w*4+(w-1-col)*4
+            temp_1 = buf[index+0]
+            temp_2 = buf[index+1]
+            temp_3 = buf[index+2]
+            buf[index+0] 
+               = buf[r_index+0] 
+            buf[index+1] 
+               = buf[r_index+1] 
+            buf[index+2] 
+               = buf[r_index+2] 
+            buf[r_index+0] 
+               = temp_1 
+            buf[r_index+1] 
+               = temp_2 
+            buf[r_index+2] 
+               = temp_3 
+            buf[index+3] = 255 
+            buf[r_index+3] = 255 
+            }
+         }
+      self.postMessage({buffer:buf.buffer},[buf.buffer])
+      })
+   }
+//
 // return values
 //
 return ({
-   mod:mod,
    name:name,
    init:init,
    inputs:inputs,