Android more reliable image compression

First: Let's look at the mass compression method first:

Java code

2. Private Bitmap Compressimage (Bitmap image) {
6. Bytearrayoutputstream BAOs = new Bytearrayoutputstream ();
8. Image.compress (Bitmap.CompressFormat.JPEG, BAOs); Mass compression method, where 100 means no compression, the compressed data stored in the BAOs
10. int options = 100;
12. while (Baos.tobytearray (). Length/ 1024>) { //cycle to determine if the image is larger than 100kb after compression, /c2>
14. Baos.reset (); //Reset BAOs to Empty BAOs
16. Image.compress (Bitmap.CompressFormat.JPEG, Options, BAOs); //Compress the options% here and store the compressed data in the BAOs
18. options = Ten; Each time, it's reduced by ten
20. }
22. Bytearrayinputstream ISBM = new Bytearrayinputstream (Baos.tobytearray ()); Store the compressed data BAOs in the Bytearrayinputstream
24. Bitmap Bitmap = Bitmapfactory.decodestream (ISBM, null, null); Generate images from the Bytearrayinputstream data
26. return bitmap;
28. }

Second: Picture by proportional size compression method (get picture according to Path and compress):

Java code

2. Private Bitmap getimage (String srcpath) {
4. Bitmapfactory.options newopts = new Bitmapfactory.options ();
6. ///start reading the picture and set the Options.injustdecodebounds back to True
8. Newopts.injustdecodebounds = true;
10. Bitmap Bitmap = Bitmapfactory.decodefile (srcpath,newopts); //Return BM to NULL at this time
14. Newopts.injustdecodebounds = false;
16. int w = newopts.outwidth;
18. int h = newopts.outheight;
20. //Now the mainstream phone is more 800*480 resolution, so the height and width we set to
22. float hh = 800f; //Set height to 800f here
24. float ww = 480f; //Set width to 480f here
26. //Zoom ratio. Because it is a fixed scale, only one of the data with high or wide is calculated
28. int be = 1; Be=1 indicates no scaling
30. If (W > H && w > ww) {//If the width is large, zoom according to the fixed width size
32. be = (int) (NEWOPTS.OUTWIDTH/WW);
34. } Else if (W < h && h > hh) {//if height is scaled according to width fixed size
36. be = (int) (NEWOPTS.OUTHEIGHT/HH);
38. }
40. if (be <= 0)
42. be = 1;
44. Newopts.insamplesize = be; //Set zoom ratio
46. //re-read the picture, note that the options.injustdecodebounds is now set back to False
48. Bitmap = Bitmapfactory.decodefile (Srcpath, newopts);
50. return Compressimage (bitmap); //compress the proportional size before compressing the mass.
52. }

Third: Image compression by proportional size (according to bitmap image compression):

Java code

2. Private Bitmap Comp (Bitmap image) {
6. Bytearrayoutputstream BAOs = new Bytearrayoutputstream ();
8. Image.compress (Bitmap.CompressFormat.JPEG, BAOs);
10. if (Baos.tobytearray (). Length/ 1024>) {//Judging if the picture is greater than 1M, Compress to avoid overflow when creating pictures (Bitmapfactory.decodestream)
12. Baos.reset (); //Reset BAOs to Empty BAOs
14. Image.compress (Bitmap.CompressFormat.JPEG, BAOs); This compresses 50% and stores the compressed data in the BAOs .
16. }
18. Bytearrayinputstream ISBM = new Bytearrayinputstream (Baos.tobytearray ());
20. Bitmapfactory.options newopts = new Bitmapfactory.options ();
22. ///start reading the picture and set the Options.injustdecodebounds back to True
24. Newopts.injustdecodebounds = true;
26. Bitmap Bitmap = Bitmapfactory.decodestream (ISBM, null, newopts);
28. Newopts.injustdecodebounds = false;
30. int w = newopts.outwidth;
32. int h = newopts.outheight;
34. //Now the mainstream phone is more 800*480 resolution, so the height and width we set to
36. float hh = 800f; //Set height to 800f here
38. float ww = 480f; //Set width to 480f here
40. //Zoom ratio. Because it is a fixed scale, only one of the data with high or wide is calculated
42. int be = 1; Be=1 indicates no scaling
44. If (W > H && w > ww) {//If the width is large, zoom according to the fixed width size
46. be = (int) (NEWOPTS.OUTWIDTH/WW);
48. } Else if (W < h && h > hh) {//if height is scaled according to width fixed size
50. be = (int) (NEWOPTS.OUTHEIGHT/HH);
52. }
54. if (be <= 0)
56. be = 1;
58. Newopts.insamplesize = be; //Set zoom ratio
60. //re-read the picture, note that the options.injustdecodebounds is now set back to False
62. ISBM = New Bytearrayinputstream (Baos.tobytearray ());
64. Bitmap = Bitmapfactory.decodestream (ISBM, null, newopts);
66. return Compressimage (bitmap); //compress the proportional size before compressing the mass.
68. }

Android more reliable image compression