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/*这是一个图象放缩类，能处理图象的按指定宽高放缩，以及图象的颜色与操作，这样能改变图象透明度
*/public class imageutil{ private static final int fp_shift = 13; private static final int fp_one = 1 << fp_shift; private static final int fp_half = 1 << (fp_shift - 1); public static final int mode_point_sample = 0; public static final int mode_box_filter = 1; public int[] getpixels(image src) { int w = src.getwidth(); int h = src.getheight(); int[] pixels = new int[w * h]; src.getrgb(pixels, 0, w, 0, 0, w, h); return pixels; } public image drawpixels(int[] pixels, int w, int h) { return image.creatergbimage(pixels, w, h, true); } public image resizeimage(image src, int destw, int desth, int mode) { int srcw = src.getwidth(); int srch = src.getheight(); // create pixel arrays int[] destpixels = new int[destw * desth]; // array to hold destination // pixels int[] srcpixels = getpixels(src); // array with source's pixels
if (mode == mode_point_sample)
{ // 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]; } } } else { // precalculate src/dest ratios int ratiow = (srcw << fp_shift) / destw; int ratioh = (srch << fp_shift) / desth;
int[] tmppixels = new int[destw * srch];
for (int y = 0; y < srch; ++y)
{ for (int destx = 0; destx < destw; ++destx) { count = 0; a = 0; r = 0; b = 0; g = 0; // initialize color blending vars int srcx = (destx * ratiow) >> fp_shift; // calculate // beginning of // sample int srcx2 = ((destx + 1) * ratiow) >> fp_shift; // calculate // end of // sample
do
{ argb = srcpixels[srcx + y * srcw]; a += ((argb & 0xff000000) >> 24); // alpha channel r += ((argb & 0x00ff0000) >> 16); // red channel g += ((argb & 0x0000ff00) >> 8); // green channel b += (argb & 0x000000ff); // blue channel ++count; // count the pixel ++srcx; // move on to the next pixel } while (srcx <= srcx2 && srcx + y * srcw < srcpixels.length);
// average out the channel values
a /= count; r /= count; g /= count; b /= count;
tmppixels[destx + y * destw] = ((a << 24) | (r << 16)
| (g << 8) | b); } }
for (int x = 0; x < destw; ++x)
{ for (int desty = 0; desty < desth; ++desty) { count = 0; a = 0; r = 0; b = 0; g = 0; // initialize color blending vars int srcy = (desty * ratioh) >> fp_shift; // calculate // beginning of // sample int srcy2 = ((desty + 1) * ratioh) >> fp_shift; // calculate // end of // sample
// now loop from srcy to srcy2 and add up the values for
// each channel do { argb = tmppixels[x + srcy * destw]; a += ((argb & 0xff000000) >> 24); // alpha channel r += ((argb & 0x00ff0000) >> 16); // red channel g += ((argb & 0x0000ff00) >> 8); // green channel b += (argb & 0x000000ff); // blue channel ++count; // count the pixel ++srcy; // move on to the next pixel } while (srcy <= srcy2 && x + srcy * destw < tmppixels.length);
// average out the channel values
a /= count; a = (a > 255) ? 255 : a; r /= count; r = (r > 255) ? 255 : r; g /= count; g = (g > 255) ? 255 : g; b /= count; b = (b > 255) ? 255 : b;
// recreate color from the averaged channels and place it
// into the destination buffer destpixels[x + desty * destw] = ((a << 24) | (r << 16) | (g << 8) | b); } } }
// return a new image created from the destination pixel buffer
return drawpixels(destpixels, destw, desth); } public image setalphapixel(image src,int eliminatepixel,int alpha,int width,int height ){ //use the source image to change the alpha pixel where the special point's pixel is the same with eliminatepixel //and return the changed image 可以用颜色的与操作改变透明度 int pixels[]=getpixels(src); for(int i=0;i<pixels.length;i++){ if(pixels[i]==eliminatepixel){ pixels[i]=pixels[i]α } } return drawpixels(pixels, width, height); }
}
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