java 图片放大缩小

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package CGameTools;

public class ZoomPixel {

public static int interpolation(int[] imageData, int width, int heigth,

float x, float y) {

// 四个最临近象素的坐标(i1, j1), (i2, j1), (i1, j2), (i2, j2)

int i1, i2;

int j1, j2;

int f1, f2, f3, f4; // 四个最临近象素值

int f12, f34; // 二个插值中间值

f1 = f2 = f3 = f4 = 0;

// 定义一个值，当象素坐标相差小于改值时认为坐标相同

int EXP = 0;

// 计算四个最临近象素的坐标

i1 = (int) x;

i2 = i1 + 1;

j1 = (int) y;

j2 = j1 + 1;

// 根据不同情况分别处理

if ((x < 0) || (x > width - 1) || (y < 0) || (y > heigth - 1)) {

return 0x00ffffff; // 要计算的点不在源图范围内，直接返回255。

} else {

if (Math.abs(x - width + 1) <= EXP) {

// 要计算的点在图像右边缘上

if (Math.abs(y - heigth + 1) <= EXP) {

// 要计算的点正好是图像最右下角那一个象素，直接返回该点象素值

f1 = (int)imageData[width * j1 + i1];

return (int)f1;

} else {

// 在图像右边缘上且不是最后一点，直接一次插值即可

f1 = (int)imageData[width * j1 + i1];

f3 = (int)imageData[width * j1 + i2];

// 返回插值结果

return (int) (f1 + (y - j1) * (f3 - f1));

}

} else if (Math.abs(y - heigth + 1) <= EXP) {

// 要计算的点在图像下边缘上且不是最后一点，直接一次插值即可

f1 = (int)imageData[width * j1 + i1];

f2 = (int)imageData[width * j2 + i1];

// 返回插值结果

return (int) (f1 + (x - i1) * (f2 - f1));

} else {

// 计算四个最临近象素值

f1 = imageData[width * j1 + i1];

f2 = imageData[width * j1 + i2];

f3 = imageData[width * j2 + i1];

f4 = imageData[width * j2 + i2];

// 插值1

f12 = (int)(f1 + (x - i1) * (f2 - f1));

// 插值2

f34 = (int)((f3 + (x - i1) * (f4 - f3)));

// 插值3

return (int)(f12 + (y - j1) * (f34 - f12));

}

}

}

}

下面是例子

处理图片：

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try {

Image src = Image.createImage("/image.png");

int destW = 400; //缩放后图片的宽度

int destH = 400; //缩放图片的高度

int srcW = src.getWidth();

int srcH = src.getHeight();

// create pixel arrays

int[] destPixels = new int[destW * destH]; // array to hold destination

int[] destRed = new int[destW * destH];

int[] destGreen = new int[destW * destH];

int[] destBlue = new int[destW * destH];

// pixels

int[] srcPixels = new int[srcW * srcH]; // array with source's pixels

int[] srcRed = new int[srcW * srcH];

int[] srcGreen = new int[srcW * srcH];

int[] srcBlue = new int[srcW * srcH];

src.getRGB(srcPixels, 0, srcW, 0, 0, srcW, srcH);

for (int i = 0; i < srcPixels.length; i++) {

srcBlue[i] = srcPixels[i]&0x000000ff;

srcGreen[i] = (srcPixels[i]>>8)&0x000000ff;

srcRed[i] = (srcPixels[i]>>16)&0x000000ff;

}

// simple point smapled resizing

// loop through the destination pixels, find the matching pixel on

// the source and use that

for (int destY = 0; destY < destH; ++destY) {

for (int destX = 0; destX < destW; ++destX) {

float srcX = ((float)destX * (float)srcW) / (float)destW;

float srcY = ((float)destY * (float)srcH) / (float)destH;

try {

destRed[destX + destY * destW] = ZoomPixel.interpolation(srcRed, srcW, srcH, srcX, srcY);

destGreen[destX + destY * destW] = ZoomPixel.interpolation(srcGreen, srcW, srcH, srcX, srcY);

destBlue[destX + destY * destW] = ZoomPixel.interpolation(srcBlue, srcW, srcH, srcX, srcY);

int value = 0xff000000;

value|=destBlue[destX + destY * destW];

value|=(destGreen[destX + destY * destW]<<8);

value|=(destRed[destX + destY * destW]<<16);

destPixels[destX + destY * destW] = value;

} catch (Exception e) {

e.printStackTrace();

}

}

}

} catch (Exception e) {

e.printStackTrace();

}

之后用：g.drawRGB(destPixels, 0, destW, 0, 0, destW, destH, false);来绘制。