README.md

@@ -10,7 +10,10 @@ systemctl enable imageshow.service
 display image:
 `curl -XPOST http://host/ --data @file.svg` or `curl -XPOST http://host/ --data-binary @file.jpg`
 
-display collor:
+draw over previous image:
+`curl -XPOST http://host/update --data @file.svg` or `curl -XPOST http://host/update --data-binary @file.jpg`
+
+display color:
 `curl -XPOST http://host/fill --data 'r=255&g=1&b=0&a=255'`
 
 show current image:

server.py

@@ -16,16 +16,37 @@ from urllib.parse import parse_qs
 
 FRAMEBUFFER = 'fb0'
 RSVGCONVERT = '/usr/bin/rsvg-convert'
-RSVGCONVERT_ARGS = ['-u', '--keep-image-data']
+RSVGCONVERT_ARGS = ['--unlimited', '--keep-image-data', '--background-color=None', '--format=png']
 BLANKINGCMD = '/usr/bin/vcgencmd'
 BLANKINGARGS_OFF = ['display_power', '0']
 BLANKINGARGS_ON = ['display_power', '1']
 
 class Server(BaseHTTPRequestHandler):
+    _processing = False
+    _payloadLength = 0
     def do_GET(self):
-        self.send_response(200)
-        self.send_header('Content-type', 'image/png')
+        self._respondCurrentImage()
+
+    def do_POST(self):
+        self._payloadLength = int(self.headers['Content-Length'])
+        if self.path == '/' or self.path == '/update':
+            self._processImage()
+        elif self.path == '/off':
+            self._setDisplayPower(False)
+        elif self.path == '/on':
+            self._setDisplayPower(True)
+        elif self.path == '/fill':
+            self._fillDisplay()
+        else:
+            self._sendResponse(404, b'Not Found')
+
+    def _sendResponse(self, code, body, contenttype = 'text/plain'):
+        self.send_response(code)
+        self.send_header('Content-type', contenttype)
         self.end_headers()
+        self.wfile.write(body)
+
+    def _respondCurrentImage(self):
         fh = open('/dev/' + FRAMEBUFFER, 'rb')
         image = Image.frombytes('RGBA', (buf_width, buf_height), fh.read(), 'raw').convert('RGBA')
         fh.close()
@@ -35,91 +56,86 @@ class Server(BaseHTTPRequestHandler):
         pngBytes = BytesIO()
         new_image.save(pngBytes, format='PNG')
 
-        self.wfile.write(pngBytes.getvalue())
-
-    def do_POST(self):
-        if self.path == '/':
-            if self.draw():
-                self.send_response(204)
-                self.end_headers()
-        elif self.path == '/off':
-            length = int(self.headers['content-length'])
-            if length:
-                self.send_response(400)
-                self.send_header('Content-type', 'text/plain')
-                self.end_headers()
-                self.wfile.write(bytes('no payload allowed', 'utf-8'))
-            else:
-                display_off()
-                self.send_response(204)
-                self.end_headers()
-        elif self.path == '/on':
-            length = int(self.headers['content-length'])
-            if length:
-                self.send_response(400)
-                self.send_header('Content-type', 'text/plain')
-                self.end_headers()
-                self.wfile.write(bytes('no payload allowed', 'utf-8'))
-            else:
-                display_on()
-                self.send_response(204)
-                self.end_headers()
-        elif self.path == '/fill':
-            display_on()
-            length = int(self.headers['content-length'])
-            postvars = parse_qs(self.rfile.read(length))
-            print(postvars)
-            buffer = bytearray()
-            buffer.extend(struct.pack('B', int(postvars[b'b'][0])))
-            buffer.extend(struct.pack('B', int(postvars[b'g'][0])))
-            buffer.extend(struct.pack('B', int(postvars[b'r'][0])))
-            buffer.extend(struct.pack('B', int(postvars[b'a'][0])))
-            buffer = buffer * (buf_width * buf_height)
-            
-            with open('/dev/' + FRAMEBUFFER, 'wb') as f:
-                f.write(buffer)
-            self.send_response(204)
-            self.end_headers()
+        self._sendResponse(200, pngBytes.getvalue(), 'image/png')
+
+    def _processImage(self):
+        if self._processing:
+            self._sendResponse(503, b'Service unavailable')
+            return
+
+        self._processing = True
+        post_data = self.rfile.read(self._payloadLength)
+
+        if post_data:
+            isUpdate = (self.path == '/update')
+            isSvg = (self.headers['Content-Type'] == 'image/svg+xml')
+            try:
+                process(post_data, isUpdate, isSvg)
+            except OSError as e:
+                print(e)
+                self._sendResponse(500, b'Internal Server Error')
+            except AssertionError as e:
+                self._sendResponse(400, bytes(str(e), 'utf-8'))
         else:
-            self.send_response(404)
-            self.send_header('Content-type', 'text/plain')
-            self.end_headers()
-            self.wfile.write(bytes('Not Found', 'utf-8'))
-
-    def draw(self):
-        content_length = int(self.headers['Content-Length'])
-        post_data = self.rfile.read(content_length)
+            self._sendResponse(400, b'Empty payload')
+        self._processing = False
+        self._sendResponse(200, b'OK')
+
+    def _fillDisplay(self):
+        self._setDisplayPower(True)
+        postvars = parse_qs(self.rfile.read(self._payloadLength))
+        print(postvars)
+        buffer = bytearray()
+        buffer.extend(struct.pack('B', int(postvars[b'b'][0])))
+        buffer.extend(struct.pack('B', int(postvars[b'g'][0])))
+        buffer.extend(struct.pack('B', int(postvars[b'r'][0])))
+        buffer.extend(struct.pack('B', int(postvars[b'a'][0])))
+        buffer = buffer * (buf_width * buf_height)
         
-        if not post_data:
-            self.send_response(400)
-            self.send_header('Content-type', 'text/plain')
-            self.end_headers()
-            self.wfile.write(bytes('Empty payload', 'utf-8'))
-            return False
-
-        return process(post_data, self)
-        
-def process(payload, http):
-    is_svg = http == False or http.headers['content-type'] == 'image/svg+xml'
-    try:
-        image = render(payload, is_svg)
-    except OSError as e:
-        print(e)
-        http.send_response(500)
-        http.send_header('Content-type', 'text/plain')
-        http.end_headers()
-        http.wfile.write(bytes('Internal Server Eror', 'utf-8'))
-        return False
-    if not check_size(image, http):
-        return False
-    image.save(last_image, format='PNG')
+        with open('/dev/' + FRAMEBUFFER, 'wb') as f:
+            f.write(buffer)
+        self._sendResponse(200, b'OK')
+    def _setDisplayPower(self, turnOn):
+        if self._payloadLength:
+            self._sendResponse(400, b'no payload allowed')
+            return
+        try:
+            setDisplayPower(turnOn)
+        except Exception as e:
+            print(e)
+        self._sendResponse(200, b'OK')
+
+buf_width = 0
+buf_height = 0
+lastImage = None
+
+def process(payload, isUpdate, isSvg):
+    global lastImage
+    image = render(payload, isSvg)
+    if not sizeIsValid(image):
+        print('Invalid size')
+        w, h = image.size
+        raise AssertionError('Size mismatch. got %dX%d. should be %dX%d' % (w,h,buf_width,buf_height))
+
+    print('size ok')
     image = convert(image)
-    draw(image)
+    if isUpdate:
+        print('drawing over last image')
+        lastImage.paste(image, (0, 0), image)
+    else:
+        lastImage = image
+    writeToFramebuffer(lastImage)
     print('done')
     return True
 
-def render(payload, is_svg):
-    if is_svg:
+def sizeIsValid(image):
+    w, h = image.size
+    if w != buf_width or h != buf_height:
+        return False
+    return True
+
+def render(payload, isSvg):
+    if isSvg:
         print('detected SVG')
         print('rendering')
         args = [RSVGCONVERT] + RSVGCONVERT_ARGS
@@ -130,63 +146,41 @@ def render(payload, is_svg):
         imageData = payload
     return Image.open(BytesIO(imageData)).convert('RGBA')
 
-def check_size(image, http):
-    w, h = image.size
-    if w != buf_width or h != buf_height:
-        print('Invalid size')
-        if http:
-            http.send_response(400)
-            http.send_header('Content-type', 'text/plain')
-            http.end_headers()
-            http.wfile.write(bytes('Size mismatch. got %dX%d. should be %dX%d' % (w,h,buf_width,buf_height), 'utf-8'))
-        return False
-    print('size ok')
-    return True
-
 def convert(image):
     print('converting')
     r,g,b,a = image.split()
     return Image.merge("RGBA", (b,g,r,a))
 
-def draw(image):
+def writeToFramebuffer(image):
     print('drawing')
-    display_on()
+    setDisplayPower(True)
     with open('/dev/' + FRAMEBUFFER, 'wb') as f:
         f.write(image.tobytes())
 
-def display_off():
-    args = [BLANKINGCMD] + BLANKINGARGS_OFF
-    try:
-        Popen(args, stdout=PIPE, stdin=PIPE, stderr=PIPE)
-    except Exception as e:
-        print(e)
-
-def display_on():
-    args = [BLANKINGCMD] + BLANKINGARGS_ON
-    try:
-        Popen(args, stdout=PIPE, stdin=PIPE, stderr=PIPE)
-    except Exception as e:
-        print(e)
-
-
+def setDisplayPower(turnOn):
+    args = [BLANKINGCMD]
+    if turnOn:
+        args += BLANKINGARGS_ON
+    else:
+        args += BLANKINGARGS_OFF
+    Popen(args, stdout=PIPE, stdin=PIPE, stderr=PIPE)
+    
 def init():
     initfile = '%dX%d.svg' % (buf_width, buf_height)
     if path.isfile(initfile):
         print('found init file')
         svg = open(initfile, 'rb')
-        process(svg.read(), False)
+        process(svg.read(), False, True)
     else:
         print('no init file found. skipping')
 
-buf_width = 0
-buf_height = 0
-last_image = BytesIO()
 def run(server_class=HTTPServer, handler_class=Server, port=80):
-    global buf_width, buf_height
+    global buf_width, buf_height, lastImage
     fbsize = open('/sys/class/graphics/' + FRAMEBUFFER + '/virtual_size', 'r')
     w, h = fbsize.read().strip().split(',')
     buf_width = int(w)
     buf_height = int(h)
+    lastImage = Image.new('RGBA', (buf_width, buf_height))
     print('detected frame buffer size %dX%d' % (buf_width, buf_height))
     chdir(path.dirname(path.realpath(__file__)))