收集了几个关于J2ME图片缩放的函数
收集了几个图像缩放函数，可能实现的方式很多，感觉这几个还是不错的，分享下
说明：以下函数都是基于MIDP2.0的，缩放后保留透明色。
代码1，resizeImage函数
收集了几个图像缩放函数，可能实现的方式很多，感觉这几个还是不错的，分享下说明：以下函数都是基于MIDP2.0的，缩放后保留透明色。
代码1，resizeImage函数
1
public
static
Image resizeImage(Image src,
int
destW,
int
destH) {
2
int
srcW
=
src.getWidth();
3
int
srcH
=
src.getHeight();
4
//
create pixel arrays
5
int
[] destPixels
=
new
int
[destW
*
destH];
//
array to hold destination
6
//
pixels
7
int
[] srcPixels
=
new
int
[srcW
*
srcH];
//
array with source's pixels
8
src.getRGB(srcPixels,
0
, srcW,
0
,
0
, srcW, srcH);
9
//
simple point smapled resizing
10
//
loop through the destination pixels, find the matching pixel on
11
//
the source and use that
12
for
(
int
destY
=
0
; destY
<
destH;
++
destY) {
13
for
(
int
destX
=
0
; destX
<
destW;
++
destX) {
14
int
srcX
=
(destX
*
srcW)
/
destW;
15
int
srcY
=
(destY
*
srcH)
/
destH;
16
destPixels[destX
+
destY
*
destW]
=
srcPixels[srcX
+
srcY
*
srcW];
17
}
18
}
19
//
return a new image created from the destination pixel buffer
20
return
Image.createRGBImage(destPixels, destW, destH,
true
);
21
}
代码2，ZoomImage函数
1
public
static
Image ZoomImage(Image src,
int
desW,
int
desH) {
2
Image desImg
=
null
;
3
int
srcW
=
src.getWidth();
//
原始图像宽
4
int
srcH
=
src.getHeight();
//
原始图像高
5
int
[] srcBuf
=
new
int
[srcW
*
srcH];
//
原始图片像素信息缓存
6
src.getRGB(srcBuf,
0
, srcW,
0
,
0
, srcW, srcH);
7
//
计算插值表
8
int
[] tabY
=
new
int
[desH];
9
int
[] tabX
=
new
int
[desW];
10
int
sb
=
0
;
11
int
db
=
0
;
12
int
tems
=
0
;
13
int
temd
=
0
;
14
int
distance
=
srcH
>
desH
?
srcH : desH;
15
for
(
int
i
=
0
; i
<=
distance; i
++
) {
/*
垂直方向
*/
16
tabY[db]
=
sb;
17
tems
+=
srcH;
18
temd
+=
desH;
19
if
(tems
>
distance) {
20
tems
-=
distance;
21
sb
++
;
22
}
23
if
(temd
>
distance) {
24
temd
-=
distance;
25
db
++
;
26
}
27
}
28
sb
=
0
;
29
db
=
0
;
30
tems
=
0
;
31
temd
=
0
;
32
distance
=
srcW
>
desW
?
srcW : desW;
33
for
(
int
i
=
0
; i
<=
distance; i
++
) {
/*
水平方向
*/
34
tabX[db]
=
(
short
) sb;
35
tems
+=
srcW;
36
temd
+=
desW;
37
if
(tems
>
distance) {
38
tems
-=
distance;
39
sb
++
;
40
}
41
if
(temd
>
distance) {
42
temd
-=
distance;
43
db
++
;
44
}
45
}
46
//
生成放大缩小后图形像素buf
47
int
[] desBuf
=
new
int
[desW
*
desH];
48
int
dx
=
0
;
49
int
dy
=
0
;
50
int
sy
=
0
;
51
int
oldy
=
-
1
;
52
for
(
int
i
=
0
; i
<
desH; i
++
) {
53
if
(oldy
==
tabY[i]) {
54
System.arraycopy(desBuf, dy
-
desW, desBuf, dy, desW);
55
}
else
{
56
dx
=
0
;
57
for
(
int
j
=
0
; j
<
desW; j
++
) {
58
desBuf[dy
+
dx]
=
srcBuf[sy
+
tabX[j]];
59
dx
++
;
60
}
61
sy
+=
(tabY[i]
-
oldy)
*
srcW;
62
}
63
oldy
=
tabY[i];
64
dy
+=
desW;
65
}
66
//
生成图片
67
desImg
=
Image.createRGBImage(desBuf, desW, desH,
true
);
68
return
desImg;
69
}
代码3
1
public
static
Image scaleImage(Image original,
int
newWidth,
int
newHeight) {
2
int
[] rawInput
=
new
int
[original.getHeight()
*
original.getWidth()];
3
original.getRGB(rawInput,
0
, original.getWidth(),
0
,
0
, original.getWidth(), original.getHeight());
4
int
[] rawOutput
=
new
int
[newWidth
*
newHeight];
5
//
YD compensates for the x loop by subtracting the width back out
6
int
YD
=
(original.getHeight()
/
newHeight)
*
original.getWidth()
-
original.getWidth();
7
int
YR
=
original.getHeight()
%
newHeight;
8
int
XD
=
original.getWidth()
/
newWidth;
9
int
XR
=
original.getWidth()
%
newWidth;
10
int
outOffset
=
0
;
11
int
inOffset
=
0
;
12
for
(
int
y
=
newHeight, YE
=
0
; y
>
0
; y
--
) {
13
for
(
int
x
=
newWidth, XE
=
0
; x
>
0
; x
--
) {
14
rawOutput[outOffset
++
]
=
rawInput[inOffset];
15
inOffset
+=
XD;
16
XE
+=
XR;
17
if
(XE
>=
newWidth) {
18
XE
-=
newWidth;
19
inOffset
++
;
20
}
21
}
22
inOffset
+=
YD;
23
YE
+=
YR;
24
if
(YE
>=
newHeight) {
25
YE
-=
newHeight;
26
inOffset
+=
original.getWidth();
27
}
28
}
29
return
Image.createRGBImage(rawOutput, newWidth, newHeight,
true
);
30
}
我将100*100的图片放到到200*200后对比了一下，ZoomImage生成的图片和另外两个函数生成的图像有点区别，感觉ZoomImage效果好点。再放大点就就基本一样了，看不出区别了。
代码4
1
/*
图像变换
*/
2
public
Image scaleImage(Image src,
int
scales1,
int
scales2)
3
{
4
return
transImage(src,src.getWidth()
*
scales1
/
scales2,src.getHeight()
*
scales1
/
scales2);
5
}
6
public
Image transImage(Image src,
int
w,
int
h)
7
{
8
int
srcW
=
src.getWidth();
9
int
srcH
=
src.getHeight();
10
int
dstW
=
w,dstH
=
h;
11
Image tmp
=
Image.createImage(dstW, srcH);
12
Graphics g
=
tmp.getGraphics();
13
int
scale
=
16
;
14
int
delta
=
(srcW
<<
scale)
/
dstW;
//
扫描长度
15
int
pos
=
delta
/
2
;
//
扫描位置
16
for
(
int
x
=
0
; x
<
dstW; x
++
)
17
{
18
g.setClip(x,
0
,
1
, srcH);
19
g.drawImage(src, x
-
(pos
>>
scale),
0
, Graphics.LEFT
|
Graphics.TOP);
20
pos
+=
delta;
21
}
22
Image dst
=
Image.createImage( dstW, dstH);
23
g
=
dst.getGraphics();
24
delta
=
(srcH
<<
scale)
/
dstH;
25
pos
=
delta
/
2
;
26
for
(
int
y
=
0
; y
<
dstH; y
++
)
27
{
28
g.setClip(
0
,y, dstW,
1
);
29
g.drawImage(tmp,
0
, y
-
(pos
>>
scale), Graphics.LEFT
|
Graphics.TOP);
30
pos
+=
delta;
31
}
32
return
dst;
33
}
34
用法举例：
1.将1张图片pic转换成176*208的图,pic=transImage(pic,176,208);
2.将1张图片pic转成原来的两倍大，pic=scaleImage(pci,2,1);
3.将一张图片pic转成原来的三分之二，pic=scaleImage(pic,2,3)
代码5，
1
public
static
final
Image scale(Image srcImage,
int
newW,
int
newH) {
2
int
srcW
=
srcImage.getWidth();
3
int
srcH
=
srcImage.getHeight();
4
//
先做水平方向上的伸缩变换
5
Image tmp
=
Image.createImage(newW, srcH);
6
Graphics g
=
tmp.getGraphics();
7
for
(
int
x
=
0
; x
<
newW; x
++
) {
8
g.setClip(x,
0
,
1
, srcH);
//
按比例放缩
9
g.drawImage(srcImage, x
-
x
*
srcW
/
newW,
0
, Graphics.LEFT
|
Graphics.TOP);
10
}
11
//
再做垂直方向上的伸缩变换
12
Image dst
=
Image.createImage(newW, newH);
13
g
=
dst.getGraphics();
14
for
(
int
y
=
0
; y
<
newH; y
++
) {
15
g.setClip(
0
, y, newW,
1
);
//
按比例放缩
16
g.drawImage(tmp,
0
, y
-
y
*
srcH
/
newH, Graphics.LEFT
|
Graphics.TOP);
17
}
18
return
dst;
19
}
以上内容转载自：http://blog.csdn.net/pjw100/archive/2009/11/26/4876053.aspx