Android模糊bitmap的工具类

た入场券 2022-08-18 13:28 216阅读 0赞

传入一个压缩好的bitmap，返回一个同等大小的模糊后的新bitmap，效率感觉还行

package com.npi.blureffect;
    
    import android.annotation.SuppressLint;
    import android.content.Context;
    import android.graphics.Bitmap;
    import android.os.Build.VERSION;
    import android.renderscript.Allocation;
    import android.renderscript.Element;
    import android.renderscript.RenderScript;
    import android.renderscript.ScriptIntrinsicBlur;
    import android.util.Log;
    
    public class Blur {
    
    	private static final String TAG = "Blur";
    
    	@SuppressLint("NewApi")
    	public static Bitmap fastblur(Context context, Bitmap sentBitmap, int radius) {
    
    		if (VERSION.SDK_INT > 16) {
    			Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);
    
    			final RenderScript rs = RenderScript.create(context);
    			final Allocation input = Allocation.createFromBitmap(rs, sentBitmap, Allocation.MipmapControl.MIPMAP_NONE,
    					Allocation.USAGE_SCRIPT);
    			final Allocation output = Allocation.createTyped(rs, input.getType());
    			final ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
    			script.setRadius(radius /* e.g. 3.f */);
    			script.setInput(input);
    			script.forEach(output);
    			output.copyTo(bitmap);
    			return bitmap;
    		}
    
    		// Stack Blur v1.0 from
    		// http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html
    		//
    		// Java Author: Mario Klingemann <mario at quasimondo.com>
    		// http://incubator.quasimondo.com
    		// created Feburary 29, 2004
    		// Android port : Yahel Bouaziz <yahel at kayenko.com>
    		// http://www.kayenko.com
    		// ported april 5th, 2012
    
    		// This is a compromise between Gaussian Blur and Box blur
    		// It creates much better looking blurs than Box Blur, but is
    		// 7x faster than my Gaussian Blur implementation.
    		//
    		// I called it Stack Blur because this describes best how this
    		// filter works internally: it creates a kind of moving stack
    		// of colors whilst scanning through the image. Thereby it
    		// just has to add one new block of color to the right side
    		// of the stack and remove the leftmost color. The remaining
    		// colors on the topmost layer of the stack are either added on
    		// or reduced by one, depending on if they are on the right or
    		// on the left side of the stack.
    		//
    		// If you are using this algorithm in your code please add
    		// the following line:
    		//
    		// Stack Blur Algorithm by Mario Klingemann <mario@quasimondo.com>
    
    		Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);
    
    		if (radius < 1) {
    			return (null);
    		}
    
    		int w = bitmap.getWidth();
    		int h = bitmap.getHeight();
    
    		int[] pix = new int[w * h];
    		Log.e("pix", w + " " + h + " " + pix.length);
    		bitmap.getPixels(pix, 0, w, 0, 0, w, h);
    
    		int wm = w - 1;
    		int hm = h - 1;
    		int wh = w * h;
    		int div = radius + radius + 1;
    
    		int r[] = new int[wh];
    		int g[] = new int[wh];
    		int b[] = new int[wh];
    		int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;
    		int vmin[] = new int[Math.max(w, h)];
    
    		int divsum = (div + 1) >> 1;
    		divsum *= divsum;
    		int dv[] = new int[256 * divsum];
    		for (i = 0; i < 256 * divsum; i++) {
    			dv[i] = (i / divsum);
    		}
    
    		yw = yi = 0;
    
    		int[][] stack = new int[div][3];
    		int stackpointer;
    		int stackstart;
    		int[] sir;
    		int rbs;
    		int r1 = radius + 1;
    		int routsum, goutsum, boutsum;
    		int rinsum, ginsum, binsum;
    
    		for (y = 0; y < h; y++) {
    			rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
    			for (i = -radius; i <= radius; i++) {
    				p = pix[yi + Math.min(wm, Math.max(i, 0))];
    				sir = stack[i + radius];
    				sir[0] = (p & 0xff0000) >> 16;
    				sir[1] = (p & 0x00ff00) >> 8;
    				sir[2] = (p & 0x0000ff);
    				rbs = r1 - Math.abs(i);
    				rsum += sir[0] * rbs;
    				gsum += sir[1] * rbs;
    				bsum += sir[2] * rbs;
    				if (i > 0) {
    					rinsum += sir[0];
    					ginsum += sir[1];
    					binsum += sir[2];
    				} else {
    					routsum += sir[0];
    					goutsum += sir[1];
    					boutsum += sir[2];
    				}
    			}
    			stackpointer = radius;
    
    			for (x = 0; x < w; x++) {
    
    				r[yi] = dv[rsum];
    				g[yi] = dv[gsum];
    				b[yi] = dv[bsum];
    
    				rsum -= routsum;
    				gsum -= goutsum;
    				bsum -= boutsum;
    
    				stackstart = stackpointer - radius + div;
    				sir = stack[stackstart % div];
    
    				routsum -= sir[0];
    				goutsum -= sir[1];
    				boutsum -= sir[2];
    
    				if (y == 0) {
    					vmin[x] = Math.min(x + radius + 1, wm);
    				}
    				p = pix[yw + vmin[x]];
    
    				sir[0] = (p & 0xff0000) >> 16;
    				sir[1] = (p & 0x00ff00) >> 8;
    				sir[2] = (p & 0x0000ff);
    
    				rinsum += sir[0];
    				ginsum += sir[1];
    				binsum += sir[2];
    
    				rsum += rinsum;
    				gsum += ginsum;
    				bsum += binsum;
    
    				stackpointer = (stackpointer + 1) % div;
    				sir = stack[(stackpointer) % div];
    
    				routsum += sir[0];
    				goutsum += sir[1];
    				boutsum += sir[2];
    
    				rinsum -= sir[0];
    				ginsum -= sir[1];
    				binsum -= sir[2];
    
    				yi++;
    			}
    			yw += w;
    		}
    		for (x = 0; x < w; x++) {
    			rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
    			yp = -radius * w;
    			for (i = -radius; i <= radius; i++) {
    				yi = Math.max(0, yp) + x;
    
    				sir = stack[i + radius];
    
    				sir[0] = r[yi];
    				sir[1] = g[yi];
    				sir[2] = b[yi];
    
    				rbs = r1 - Math.abs(i);
    
    				rsum += r[yi] * rbs;
    				gsum += g[yi] * rbs;
    				bsum += b[yi] * rbs;
    
    				if (i > 0) {
    					rinsum += sir[0];
    					ginsum += sir[1];
    					binsum += sir[2];
    				} else {
    					routsum += sir[0];
    					goutsum += sir[1];
    					boutsum += sir[2];
    				}
    
    				if (i < hm) {
    					yp += w;
    				}
    			}
    			yi = x;
    			stackpointer = radius;
    			for (y = 0; y < h; y++) {
    				// Preserve alpha channel: ( 0xff000000 & pix[yi] )
    				pix[yi] = (0xff000000 & pix[yi]) | (dv[rsum] << 16) | (dv[gsum] << 8) | dv[bsum];
    
    				rsum -= routsum;
    				gsum -= goutsum;
    				bsum -= boutsum;
    
    				stackstart = stackpointer - radius + div;
    				sir = stack[stackstart % div];
    
    				routsum -= sir[0];
    				goutsum -= sir[1];
    				boutsum -= sir[2];
    
    				if (x == 0) {
    					vmin[y] = Math.min(y + r1, hm) * w;
    				}
    				p = x + vmin[y];
    
    				sir[0] = r[p];
    				sir[1] = g[p];
    				sir[2] = b[p];
    
    				rinsum += sir[0];
    				ginsum += sir[1];
    				binsum += sir[2];
    
    				rsum += rinsum;
    				gsum += ginsum;
    				bsum += binsum;
    
    				stackpointer = (stackpointer + 1) % div;
    				sir = stack[stackpointer];
    
    				routsum += sir[0];
    				goutsum += sir[1];
    				boutsum += sir[2];
    
    				rinsum -= sir[0];
    				ginsum -= sir[1];
    				binsum -= sir[2];
    
    				yi += w;
    			}
    		}
    
    		Log.e("pix", w + " " + h + " " + pix.length);
    		bitmap.setPixels(pix, 0, w, 0, 0, w, h);
    		return (bitmap);
    	}
    
    }

调用方法

final File blurredImage = new File(getFilesDir() + "blurred_image.png");

BitmapFactory.Options options = new BitmapFactory.Options();
    options.inSampleSize = 2;
    Bitmap image = BitmapFactory.decodeResource(getResources(), R.drawable.image, options);//把原图缩小为现图的一半，然后再对这个缩小的图片进行虚化
    Bitmap newImg = Blur.fastblur(MainActivity.this, image, 12);//第三个参数是模糊程度
    ImageUtils.storeImage(newImg, file);//将虚化的图片缓存到文件

另外再附一个缓存bitmap到file的方法，减少内存开销，并且可以先把图片处理好了之后到别的activity进行调用

package com.npi.blureffect;
    
    import java.io.File;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
    
    import android.annotation.SuppressLint;
    import android.app.Activity;
    import android.graphics.Bitmap;
    import android.graphics.Point;
    import android.os.Build;
    import android.util.Log;
    import android.view.Display;
    
    public class ImageUtils {
    	private static final String TAG = "ImageUtils";
    
    	/**
    	 * Stores an image on the storage
    	 * 
    	 * @param image
    	 *            the image to store.
    	 * @param pictureFile
    	 *            the file in which it must be stored
    	 */
    	public static void storeImage(Bitmap image, File pictureFile) {
    		if (pictureFile == null) {
    			Log.d(TAG, "Error creating media file, check storage permissions: ");
    			return;
    		}
    		try {
    			FileOutputStream fos = new FileOutputStream(pictureFile);
    			image.compress(Bitmap.CompressFormat.PNG, 90, fos);
    			fos.close();
    		} catch (FileNotFoundException e) {
    			Log.d(TAG, "File not found: " + e.getMessage());
    		} catch (IOException e) {
    			Log.d(TAG, "Error accessing file: " + e.getMessage());
    		}
    	}
    }

这个缓存的调用方法

Bitmap bmpBlurred = BitmapFactory.decodeFile(getFilesDir() +  "blurred\_image.png");