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PImage to byte array for use with Android's BitmapFactory

[3 Replies]
- 10-Sep-2013 03:16 PM
- Forum: Android Processing
Hi everyone,

I'm trying to use this code from Daniel Shiffman, translating the necessary parts to Android's graphics library (since Android doesn't include awt libraries). http://shiffman.net/2010/11/13/streaming-video-with-udp-in-processing/ I'm basically trying to stream video from an Android tablet to a Processing sketch running on a PC, both connected to the same WiFi network. Like using the tablet as a wireless webcam. NOTE: I'm using a still to test this out but I'll use the tablet's camera, that's why I can't use "file to byte array" methods.

I have to convert a PImage to a byte array that is usable with Android's BitmapFactory.decodeByteArray() . How do I do that?

I tried looping through the pixels[] and passing it to an int array but, when I translate this to bytes, the BitmapFactory can't use it.

BitmapFactory docs: http://developer.android.com/reference/android/graphics/BitmapFactory.html

Here is the image I'm using: http://3.bp.blogspot.com/-GMpXUe3kKkU/Tgn5CInbVxI/AAAAAAAAIpQ/cs0AICtd9Ao/s320/picasso_woman_b.jpg

Thanks in advance for all the help you can give me!!

Here is the code so far (Line 61 is how I know my byte array is not working, it returns null):
1. import java.net.*;
2. import java.io.*;
3. import java.nio.*;
4. import ketai.net.*;
5. import android.graphics.*;
7. PImage myimg;
8. int[] myPixels;
10. int clientPort = 9100;
11. DatagramSocket ds;
12. String myIPAddress;
13. String remoteAddress = "192.168.0.104";//PC Local IP address. REPLACE WITH YOUR IP ADDRESS
15. void setup()
16. {
17. size(192,262);
19. orientation(PORTRAIT);
20. imageMode(CENTER);
21. myIPAddress = KetaiNet.getIP();
23. myimg = loadImage("picasso_woman_b.jpg");
25. try
26. {
27. ds = new DatagramSocket();
28. }
29. catch (SocketException e)
30. {
31. e.printStackTrace();
32. }
33. broadcast(myimg);
36. }
38. void draw()
39. {
40. image(myimg,width/2 , height/2);
41. }
43. void broadcast(PImage img)
44. {
45. //Convertir pixels[] en int[]
46. myPixels = new int[img.width*img.height];
47. img.loadPixels();
48. for(int i = 0; i<img.width*img.height; i++)
49. {
50. myPixels[i]= img.pixels[i];
51. }
53. //Convert int[] to byte[]
54. ByteBuffer byteBuffer = ByteBuffer.allocate(img.width*img.height * 4);
55. IntBuffer intBuffer = byteBuffer.asIntBuffer();
56. intBuffer.put(myPixels);
57. byte[] imgByteArray = byteBuffer.array();
59. //Use byte[] with BitmapFactory
60. Bitmap bitmap = BitmapFactory.decodeByteArray(imgByteArray, 0, imgByteArray.length);
61. println(bitmap);//HERE IS WHERE I FOUND MY BYTE ARRAY IS NOT VALID, SINCE IT RETUNRS NULL
63. // Need these output streams to get image as bytes for UDP communication
64. ByteArrayOutputStream baStream = new ByteArrayOutputStream();
65. bitmap.compress(Bitmap.CompressFormat.JPEG, 50, baStream);//Compress bitmap to be able to stream it
66. BufferedOutputStream bos = new BufferedOutputStream(baStream);
68. // Get the byte array, which we will send out via UDP!
69. byte[] packet = baStream.toByteArray();
71. // Send JPEG data as a datagram
72. println("Sending datagram with " + packet.length + " bytes");
73. try
74. {
75. ds.send(new DatagramPacket(packet,packet.length, InetAddress.getByName(remoteAddress),clientPort));
76. }
77. catch (Exception e)
78. {
79. e.printStackTrace();
80. }
81. }

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