allow saving and setting exposure/shutter, gain and balance so that i…

…t can be frozen during timelapse

adafruit_pycamera/__init__.py

@@ -882,6 +882,55 @@ def led_color(self, new_color):
         else:
             self.pixels[:] = colors
 
+    def get_camera_autosettings(self):
+        exposure = (self.read_camera_register(0x3500) << 12) + \
+                  (self.read_camera_register(0x3501) << 4) + \
+                  (self.read_camera_register(0x3502) >> 4);
+        wb = [self.read_camera_register(x) for x in \
+              (0x3400, 0x3401, 0x3402, 0x3403, 0x3404, 0x3405)]
+
+        settings = {
+            'gain': self.read_camera_register(0x350b),
+            'exposure': exposure,
+            'wb': wb
+            }
+        return settings
+
+    def set_camera_wb(self, wb_register_values=None):
+        if wb_register_values is None:
+            # just set to auto balance
+            self.camera.whitebal = True
+            return
+
+        if len(wb_register_values) != 6:
+            raise RuntimeError("Please pass in 0x3400~0x3405 inclusive!")
+
+        self.write_camera_register(0x3212, 0x03)
+        self.write_camera_register(0x3406, 0x01)
+        for i, reg_val in enumerate(wb_register_values):
+            self.write_camera_register(0x3400+i, reg_val)
+        self.write_camera_register(0x3212, 0x13)
+        self.write_camera_register(0x3212, 0xa3)
+
+    def set_camera_exposure(self, new_exposure=None):
+        if new_exposure is None:
+            # just set auto expose
+            self.camera.exposure_ctrl = True
+            return
+        exposure_ctrl = False
+
+        self.write_camera_register(0x3500, (new_exposure >> 12) & 0xFF)
+        self.write_camera_register(0x3501, (new_exposure >> 4) & 0xFF)
+        self.write_camera_register(0x3502, (new_exposure << 4) & 0xFF)
+
+    def set_camera_gain(self, new_gain=None):
+        if new_gain is None:
+            # just set auto expose
+            self.camera.gain_ctrl = True
+            return
+
+        self.camera.gain_ctrl = False
+        self.write_camera_register(0x350b, new_gain)
 
 class PyCamera(PyCameraBase):
     """Wrapper class for the PyCamera hardware"""

examples/camera/code.py

@@ -225,7 +225,20 @@
         print("OK")
         if pycam.mode_text == "LAPS":
             if timelapse_remaining is None: # stopped
+                print("Starting timelapse")
                 timelapse_remaining = pycam.timelapse_rates[pycam.timelapse_rate]
                 timelapse_timestamp = time.time() + timelapse_remaining + 1
+                # dont let the camera take over auto-settings
+                saved_settings = pycam.get_camera_autosettings()
+                #print(f"Current exposure {saved_settings['exposure']}, gain {saved_settings['gain']}, wb {saved_settings['wb']}")
+                pycam.set_camera_exposure(saved_settings['exposure'])
+                pycam.set_camera_gain(saved_settings['gain'])
+                pycam.set_camera_wb(saved_settings['wb'])
             else: # is running, turn off
+                print("Stopping timelapse")
+
                 timelapse_remaining = None
+                pycam.camera.exposure_ctrl = True
+                pycam.set_camera_gain(None) # go back to autogain
+                pycam.set_camera_wb(None) # go back to autobalance
+                pycam.set_camera_exposure(None) # go back to auto shutter