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
public static Image resizeImage(Image src, int destW, int destH) { int srcW = src.getWidth(); int srcH = src.getHeight(); // create pixel arrays int[] destPixels = new int[destW * destH]; // array to hold destination // pixels int[] srcPixels = new int[srcW * srcH]; // array with source's pixels src.getRGB(srcPixels, 0, srcW, 0, 0, srcW, srcH); // 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) { int srcX = (destX * srcW) / destW; int srcY = (destY * srcH) / destH; destPixels[destX + destY * destW] = srcPixels[srcX + srcY * srcW]; } } // return a new image created from the destination pixel buffer return Image.createRGBImage(destPixels, destW, destH, true); }

 

代码2，ZoomImage函数

public static Image ZoomImage(Image src, int desW, int desH) { Image desImg = null; int srcW = src.getWidth(); // 原始图像宽 int srcH = src.getHeight(); // 原始图像高 int[] srcBuf = new int[srcW * srcH]; // 原始图片像素信息缓存 src.getRGB(srcBuf, 0, srcW, 0, 0, srcW, srcH); // 计算插值表 int[] tabY = new int[desH]; int[] tabX = new int[desW]; int sb = 0; int db = 0; int tems = 0; int temd = 0; int distance = srcH > desH ? srcH : desH; for (int i = 0; i <= distance; i++) { /* 垂直方向 */ tabY[db] = sb; tems += srcH; temd += desH; if (tems > distance) { tems -= distance; sb++; } if (temd > distance) { temd -= distance; db++; } } sb = 0; db = 0; tems = 0; temd = 0; distance = srcW > desW ? srcW : desW; for (int i = 0; i <= distance; i++) { /* 水平方向 */ tabX[db] = (short) sb; tems += srcW; temd += desW; if (tems > distance) { tems -= distance; sb++; } if (temd > distance) { temd -= distance; db++; } } // 生成放大缩小后图形像素buf int[] desBuf = new int[desW * desH]; int dx = 0; int dy = 0; int sy = 0; int oldy = -1; for (int i = 0; i < desH; i++) { if (oldy == tabY[i]) { System.arraycopy(desBuf, dy - desW, desBuf, dy, desW); } else { dx = 0; for (int j = 0; j < desW; j++) { desBuf[dy + dx] = srcBuf[sy + tabX[j]]; dx++; } sy += (tabY[i] - oldy) * srcW; } oldy = tabY[i]; dy += desW; } // 生成图片 desImg = Image.createRGBImage(desBuf, desW, desH, true); return desImg; }

 

代码3，

public static Image scaleImage(Image original, int newWidth, int newHeight) { int[] rawInput = new int[original.getHeight() * original.getWidth()]; original.getRGB(rawInput, 0, original.getWidth(), 0, 0, original.getWidth(), original.getHeight()); int[] rawOutput = new int[newWidth * newHeight]; // YD compensates for the x loop by subtracting the width back out int YD = (original.getHeight() / newHeight) * original.getWidth() - original.getWidth(); int YR = original.getHeight() % newHeight; int XD = original.getWidth() / newWidth; int XR = original.getWidth() % newWidth; int outOffset = 0; int inOffset = 0; for (int y = newHeight, YE = 0; y > 0; y--) { for (int x = newWidth, XE = 0; x > 0; x--) { rawOutput[outOffset++] = rawInput[inOffset]; inOffset += XD; XE += XR; if (XE >= newWidth) { XE -= newWidth; inOffset++; } } inOffset += YD; YE += YR; if (YE >= newHeight) { YE -= newHeight; inOffset += original.getWidth(); } } return Image.createRGBImage(rawOutput, newWidth, newHeight, true); }

 

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
/*图像变换*/ public Image scaleImage(Image src,int scales1,int scales2) { return transImage(src,src.getWidth()*scales1/scales2,src.getHeight()*scales1/scales2); } public Image transImage(Image src, int w, int h) { int srcW = src.getWidth(); int srcH = src.getHeight(); int dstW=w,dstH=h; Image tmp = Image.createImage(dstW, srcH); Graphics g = tmp.getGraphics(); int scale=16; int delta = (srcW << scale) / dstW;//扫描长度 int pos = delta / 2;//扫描位置 for (int x = 0; x < dstW; x++) { g.setClip(x, 0, 1, srcH); g.drawImage(src, x - (pos >> scale), 0, Graphics.LEFT | Graphics.TOP); pos += delta; } Image dst = Image.createImage( dstW, dstH); g = dst.getGraphics(); delta = (srcH << scale) / dstH; pos = delta / 2; for (int y = 0; y < dstH; y++) { g.setClip(0,y, dstW, 1); g.drawImage(tmp, 0, y - (pos >> scale), Graphics.LEFT | Graphics.TOP); pos += delta; } return dst; }

 

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，
public static final Image scale(Image srcImage, int newW, int newH) { int srcW = srcImage.getWidth(); int srcH = srcImage.getHeight(); //先做水平方向上的伸缩变换 Image tmp = Image.createImage(newW, srcH); Graphics g = tmp.getGraphics(); for (int x = 0; x < newW; x++) { g.setClip(x, 0, 1, srcH); //按比例放缩 g.drawImage(srcImage, x - x * srcW / newW, 0, Graphics.LEFT | Graphics.TOP); } //再做垂直方向上的伸缩变换 Image dst = Image.createImage(newW, newH); g = dst.getGraphics(); for (int y = 0; y < newH; y++) { g.setClip(0, y, newW, 1); //按比例放缩 g.drawImage(tmp, 0, y - y * srcH / newH, Graphics.LEFT | Graphics.TOP); } return dst; }