Transcript TouchDevelop Chapter5-7

TouchDevelop Chapter 5-7
Chapter 5 Audio
Chapter 6 Camera, Graphics and Video
Chapter 7 Sensors
Mengfei Ren
5 Audio
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5-1 Music
5-2 Radio
5-3 Sounds
5-4 Microphone
5-5 Media Player on a Home Network
5 Audio
• A smartphone could play music such as MP3
files, audio streamed over the internet or media
center
• All the media files could be synchronized to
the phone using Zune, or purchased and
downloaded via the Marketplace and the
Internet
5-1 Music
• The smartphone supports three music formats, AAC,
MP3, and WMA.
• The TouchDevelop API provides the media resource
for retrieving collections of all the songs, albums, and
playlists. However, these collections couldn’t
changed by TouchDevelop. [1]
5-1 Methods for Songs, Albums and
Playlists
[1]
5-1 Methods for Songs, Albums and
Playlists(cont.)
[1]
5-1 Play the Songs
• When there is new album or playlist sent to the
player, it creates a queue of songs to be played.
The songs will be played in order that they
appear in the album or playlist.
• Requesting to play a new song when there is a
song playing, the current one will be
terminated and the queue be cleared before the
new one starts.
• Playing songs is a background event.[1]
• Demo 5-1
5-1 Methods for Playing Songs
5-1 Methods for Playing Songs
• The song’s volume ranges from 0.0 to 1.0.
• The value of 0.0 means mute, however the
value of 1.0 does not mean the maximum
which the phone is capable.
• The value of 1.0 is related to the current
volume of the cell phone.
• If the phone is under mute mode, the speaker is
set to off and there is no any audible sounds.
5-2 Radio
• The radio plays as a background activity.
• The radio will only stop if the method radio
stop is called or if the user shuts off the
radio externally to the script. [1] Demo 5-2
5-3 Sounds
• The Sound datatype is used for audio
recordings in the WAV format.
• The files in WAV format is commonly used
used for short sound clips (30 seconds or
less).[1]
– This format is commonly used for uncompressed
audio and therefore the files tend to be large.
– No method is provided for stopping playback of
the clip before it is finished.
5-3 Methods for Sound Datatype
5-4 Microphone
• API for making a recoding
var snd := senses  record microphone
• The word “Recording…” and a stop button
will be displayed on the screen.
5-5 Media Player on a Home Network
• A media center can transmit videos and music
onto the phone over a Wi-Fi network. The
phone could be a remote control for the media
player.
• TouchDevelop provides the Media Server
datatype for a media center. The script could
search and retrieve the songs and videos.
• To play a song from media server:
player  play home media (mlink)
• Demo 5-3
5-5 Methods for Media Server[1]
6 Camera, Graphics, Video
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6-1 Camera
6-2 Static Graphics Drawing and Display
6-3 Playing Videos from the Internet
6-4 Media Player
6-1 Camera
• To create the picture, the cell phone should at least
have a camera on the back, which is the primary
camera.
• To access the camera, TouchDevelop provides the
senses service. Also the Camera datatype to retrieve
information about the camera and take a quick lowquality picture.
• To show the picture on the wall, there are two
methods.
6-1 Ways to Take Pictures
• High-quality picture:
senses  take camera picture
• Not immediately take the picture. It calls the
phone’s built-in software for using the camera
and displays a preview image on the screen. Take
the picture until the button pressed.
• Low-quality picture:
senses front camera  preview
• Demo 6-1
Demo
6-2
[2]
6-1 Picture Effects
[2]
Example: Picture Overlaying
• Demo 6-6
6-2 Static Graphics Drawing
• TouchDevelop provides many methods for
drawing lines and shapes.
• The create picture method is to create a new
board to draw lines and shapes.
var pic := media  create picture(400,200)
• Demo 6-3
6-2 Drawing Methods Picture
[2]
6-3 Playing Videos from the Internet
• TouchDevelop doesn’t provide access to video
files held on the phone. Nor can a script
download a video to the phone.
• A script can access and play videos which are
streamed from the internet or a media server.[2]
• Demo 6-4
6-4 Media Player
• A media center could send pictures to the
phone and stream videos to the phone.
[2]
6-4 Media Player (cont.)
• Demo 6-5
• TouchDevelop does not provide methods to
stop the video playing from within the script.
• To stop the playing video,
– Tap the screen and see the pause/continue button
– Pause the video and tap the back button to stop the
execution in the script.
7 Sensors
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7-1 The Sensors
7-2 Sensor-Driven Events
7-3 Accelerometer
7-4 Compass
7-5 Gyroscope
7-6 Motion
7-1 Sensors
• GPS(Global Positioning System): obtains the
phone’s current location on the map
• Accelerometer: measures gravitational and
acceleration
• Compass: returns the direction of magnetic
north
• Gyroscope: measures the phone’s orientation
in 3D space [3]
7-1 Sensing Methods [3]
7-2 Sensor-Driven Events
• A script can use the event of effect an action,
such as pausing the playback of an audio
recoding.
[3]
• Demo 7-1
7-3 Accelerometer
• The phone measures the force by the
accelerometer when it is shaken or moved,
which combines acceleration with gravity.
• The acceleration is in any direction in three
dimensional space. The TouchDevelop API use
the Vector3 datatype to present the current
force in three dimensions.
• Demo 7-2, 7-3
7-3 Accelerometer (cont.)
[3]
• (0,0,-1) – the phone is
lying flat on the table
• (0,-1,0) – the phone is
held vertically with its
bottom edge on the table
• The TouchDevelop
reports the force in g
(gravitational) units.
• Any stationary object is
subjected to a force of
1g in the downwards
direction
7-4 Compass
• Report the phone’s orientation with respect to
magnetic north.
• Demo 7-4
7-5 Gyroscope
• This is a device which reports on whether the
phone is being rotated in any orientation.
• Rotation is measured as an angular velocity,
which is rotation speed in degrees per second
about an axis in three dimensional space.
• (a, b, c) – the combined speed is (𝑎2 + 𝑏2 + 𝑐 2 )
• Example: (360,0,0) – a rotational speed that the
X axis in a clockwise direction.
7-6 Motion
• The TouchDevelop provides the Motion
datatype to present the current location which
is measured by the combination of the various
sensor components.
[3]
7-6 Motion (cont.)
• The force caused by gravity and the additional
force caused by acceleration is separated. The
method just returns a true acceleration without
the gravitational force.
• The accurate value of the orientation can be
obtained for the time when it was captured.
The true orientation is known as its attitude
that measured via three methods, pitch, roll
and yaw.
7-6 Motion (cont.)
• These methods is measured in degrees,
respectively relative to three orthogonal axes.
• The axes are diagrammed in the plane.
References
[1] https://az31353.vo.msecnd.net/cpd/kyeibookchapter5.pdf
[2] https://az31353.vo.msecnd.net/cpd/axwqbookchapter6.pdf
[3] https://az31353.vo.msecnd.net/cpd/mxnlbookchapter7.pdf