Android 去除 bitmap 无用的白色边框

来源：互联网发布：薪酬优化密件工资单编辑：程序博客网时间：2024/05/01 18:36
图示

如下图所示，本文所写的工具类是，去除内容区域以外的白色边框。
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代码

import android.graphics.Bitmap;/** * Created by Victor Yang on 2016/6/17. * 去除 bitmap 无用的白色边框 */public class BitmapDeleteNoUseSpaceUtil {    /**     * 灰度化 bitmap     * @param imgTheWidth     * @param imgTheHeight     * @param imgThePixels     * @return     */    private static Bitmap getGrayImg(int imgTheWidth, int imgTheHeight, int[] imgThePixels) {        int alpha = 0xFF << 24;  //设置透明度        for (int i = 0; i < imgTheHeight; i++) {            for (int j = 0; j < imgTheWidth; j++) {                int grey = imgThePixels[imgTheWidth * i + j];                int red = ((grey & 0x00FF0000) >> 16);  //获取红色灰度值                int green = ((grey & 0x0000FF00) >> 8); //获取绿色灰度值                int blue = (grey & 0x000000FF);         //获取蓝色灰度值                grey = (int) ((float) red * 0.3 + (float) green * 0.59 + (float) blue * 0.11);                grey = alpha | (grey << 16) | (grey << 8) | grey; //添加透明度                imgThePixels[imgTheWidth * i + j] = grey;   //更改像素色值            }        }        Bitmap result =                Bitmap.createBitmap(imgTheWidth, imgTheHeight, Bitmap.Config.RGB_565);        result.setPixels(imgThePixels, 0, imgTheWidth, 0, 0, imgTheWidth, imgTheHeight);        return result;    }    /**     * 去除多余白框     * @param originBitmap     * @return     */    public static Bitmap deleteNoUseWhiteSpace(Bitmap originBitmap) {        int[] imgThePixels = new int[originBitmap.getWidth() * originBitmap.getHeight()];        originBitmap.getPixels(                imgThePixels,                0,                originBitmap.getWidth(),                0,                0,                originBitmap.getWidth(),                originBitmap.getHeight());        // 灰度化 bitmap        Bitmap bitmap = getGrayImg(                originBitmap.getWidth(),                originBitmap.getHeight(),                imgThePixels);        int top = 0;  // 上边框白色高度        int left = 0; // 左边框白色高度        int right = 0; // 右边框白色高度        int bottom = 0; // 底边框白色高度        for (int h = 0; h < bitmap.getHeight(); h++) {            boolean holdBlackPix = false;            for (int w = 0; w < bitmap.getWidth(); w++) {                if (bitmap.getPixel(w, h) != -1) { // -1 是白色                    holdBlackPix = true; // 如果不是-1 则是其他颜色                    break;                }            }            if (holdBlackPix) {                break;            }            top++;        }        for (int w = 0; w < bitmap.getWidth(); w++) {            boolean holdBlackPix = false;            for (int h = 0; h < bitmap.getHeight(); h++) {                if (bitmap.getPixel(w, h) != -1) {                    holdBlackPix = true;                    break;                }            }            if (holdBlackPix) {                break;            }            left++;        }        for (int w = bitmap.getWidth() - 1; w >= 0; w--) {            boolean holdBlackPix = false;            for (int h = 0; h < bitmap.getHeight(); h++) {                if (bitmap.getPixel(w, h) != -1) {                    holdBlackPix = true;                    break;                }            }            if (holdBlackPix) {                break;            }            right++;        }        for (int h = bitmap.getHeight() - 1; h >= 0; h--) {            boolean holdBlackPix = false;            for (int w = 0; w < bitmap.getWidth(); w++) {                if (bitmap.getPixel(w, h) != -1) {                    holdBlackPix = true;                    break;                }            }            if (holdBlackPix) {                break;            }            bottom++;        }        // 获取内容区域的宽高        int cropHeight = bitmap.getHeight() - bottom - top;        int cropWidth = bitmap.getWidth() - left - right;        // 获取内容区域的像素点        int[] newPix = new int[cropWidth * cropHeight];        int i = 0;        for (int h = top; h < top + cropHeight; h++) {            for (int w = left; w < left + cropWidth; w++) {                newPix[i++] = bitmap.getPixel(w, h);            }        }        // 创建切割后的 bitmap， 针对彩色图，把 newPix 替换为 originBitmap 的 pixs        return Bitmap.createBitmap(newPix, cropWidth, cropHeight, Bitmap.Config.ARGB_8888);    }}
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