Android 图片添加水印

最新推荐文章于 2025-10-14 14:04:18 发布

原创最新推荐文章于 2025-10-14 14:04:18 发布 · 4.9k 阅读

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本文详细介绍了ImageUtil工具类的功能，包括如何在图片上添加水印、绘制文字、缩放图片以及单位转换等操作。提供了具体的实现代码和调用示例，适用于Android应用开发中图片处理的需求。

ImageUtil 工具类

package com.njhhsoft.egj.util;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Rect;

public class ImageUtil {

    private static Bitmap createWaterMaskBitmap(Bitmap src, Bitmap watermark,
                                                int paddingLeft, int paddingTop) {
        if (src == null) {
            return null;
        }
        int width = src.getWidth();
        int height = src.getHeight();
        //创建一个bitmap
        Bitmap newb = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);// 创建一个新的和SRC长度宽度一样的位图
        //将该图片作为画布
        Canvas canvas = new Canvas(newb);
        //在画布 0，0坐标上开始绘制原始图片
        canvas.drawBitmap(src, 0, 0, null);
        //在画布上绘制水印图片
        canvas.drawBitmap(watermark, paddingLeft, paddingTop, null);
        // 保存
        canvas.save(Canvas.ALL_SAVE_FLAG);
        // 存储
        canvas.restore();
        return newb;
    }

    /**
     * 绘制文字到右下角
     * @param context
     * @param bitmap
     * @param text
     * @param size
     * @param color
     * @param paddingBottom
     * @param paddingRight
     * @return
     */
    public static Bitmap drawTextToRightBottom(Context context, Bitmap bitmap, String text, String name, String ctx,
             String text1, String name1, String ctx1,
                                               int size, int color, int paddingRight, int paddingBottom) {
        Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setColor(color);
        paint.setTextSize(dp2px(context, size));
        Rect bounds = new Rect();
        paint.getTextBounds(text, 0, text.length(), bounds);
        return drawTextToBitmap(context, bitmap, text,name, ctx,text1,name1, ctx1, paint, bounds,
                bitmap.getWidth() - bounds.width() - dp2px(context, paddingRight),
                bitmap.getHeight() - dp2px(context, paddingBottom));
    }




    //图片上绘制文字
    private static Bitmap drawTextToBitmap(Context context, Bitmap bitmap, String text, String name, String ctx,
                                           String text1, String name1, String ctx1,
                                           Paint paint, Rect bounds, int paddingLeft, int paddingTop) {
        android.graphics.Bitmap.Config bitmapConfig = bitmap.getConfig();

        paint.setDither(true); // 获取跟清晰的图像采样
        paint.setFilterBitmap(true);// 过滤一些
        if (bitmapConfig == null) {
            bitmapConfig = android.graphics.Bitmap.Config.ARGB_8888;
        }
        bitmap = bitmap.copy(bitmapConfig, true);
        Canvas canvas = new Canvas(bitmap);
        canvas.drawText(text, paddingLeft, paddingTop, paint);
        canvas.drawText(name, paddingLeft, paddingTop+100, paint);
        canvas.drawText(ctx, paddingLeft, paddingTop+200, paint);

        canvas.drawText(text1, paddingLeft, paddingTop+300, paint);
        canvas.drawText(name1, paddingLeft, paddingTop+400, paint);
        canvas.drawText(ctx1, paddingLeft, paddingTop+500, paint);

        return bitmap;
    }

    /**
     * 缩放图片
     * @param src
     * @param w
     * @param h
     * @return
     */
    public static Bitmap scaleWithWH(Bitmap src, double w, double h) {
        if (w == 0 || h == 0 || src == null) {
            return src;
        } else {
            // 记录src的宽高
            int width = src.getWidth();
            int height = src.getHeight();
            // 创建一个matrix容器
            Matrix matrix = new Matrix();
            // 计算缩放比例
            float scaleWidth = (float) (w / width);
            float scaleHeight = (float) (h / height);
            // 开始缩放
            matrix.postScale(scaleWidth, scaleHeight);
            // 创建缩放后的图片
            return Bitmap.createBitmap(src, 0, 0, width, height, matrix, true);
        }
    }

    /**
     * dip转pix
     * @param context
     * @param dp
     * @return
     */
    public static int dp2px(Context context, float dp) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dp * scale + 0.5f);
    }


}

Activity中的调用方式