J2's Image Scaling

 

I used to collect this function on the internet, regardless of the effect or performance. I only think it is very useful.
It took a long time, but unfortunately I don't know who it is. Thank you for the author.
This function uses the getrgb () function of midp2.0, which is efficient. Basically, there is nothing to optimize.

1. Public static image zoomimage (image SRC, int desw, int Desh ){
2. Image desimg = NULL;
3. Int srcw = SRC. getwidth (); // Original Image Width
4. Int srch = SRC. getheight (); // The height of the original image.
5. Int [] srcbuf = new int [srcw * srch]; // cache the pixel information of the original image.
7. SRC. getrgb (srcbuf, 0, srcw, 0, 0, srcw, srch );
9. // Calculate the interpolation table
10. Int [] taby = new int [Desh];
11. Int [] tabx = new int [desw];
13. Int sb = 0;
14. Int DB = 0;
15. Int tems = 0;
16. Int temd = 0;
17. Int distance = srch> Desh? Srch: Desh;
18. For (INT I = 0; I <= distance; I ++) {/* vertical */
19. Taby [dB] = Sb;
20. Tems + = srch;
21. Temd + = Desh;
22. If (TEMS> distance ){
23. Tems-= distance;
24. SB ++;
25. }
26. If (temd> distance ){
27. Temd-= distance;
28. DB ++;
29. }
30. }
32. SB = 0;
33. DB = 0;
34. Tems = 0;
35. Temd = 0;
36. Distance = srcw> desw? Srcw: desw;
37. For (INT I = 0; I <= distance; I ++) {/* horizontal direction */
38. Tabx [dB] = (short) Sb;
39. Tems + = srcw;
40. Temd + = desw;
41. If (TEMS> distance ){
42. Tems-= distance;
43. SB ++;
44. }
45. If (temd> distance ){
46. Temd-= distance;
47. DB ++;
48. }
49. }
51. // Generate the image pixel Buf after zoom-in and zoom-out
52. Int [] desbuf = new int [desw * Desh];
53. Int dx = 0;
54. Int DY = 0;
55. Int Sy = 0;
56. Int Oldy =-1;
57. For (INT I = 0; I <Desh; I ++ ){
58. If (Oldy = taby [I]) {
59. System. arraycopy (desbuf, Dy-desw, desbuf, Dy, desw );
60. } Else {
61. DX = 0;
62. For (Int J = 0; j <desw; j ++ ){
63. Desbuf [dy + dx] = srcbuf [SY + tabx [J];
64. DX ++;
65. }
66. SY + = (taby [I]-Oldy) * srcw;
67. }
68. Oldy = taby [I];
69. Dy + = desw;
70. }
72. // Generate an image
73. Desimg = image. creatergbimage (desbuf, desw, Desh, false );
74. Return desimg;
75. }