我們在做項目的時候有時候需要給圖片添加水印，水寒今天就遇到了這樣的問題，所以搞了一個工具類，貼出來大家直接調用就行。
/** * 圖片工具類 * @author 水寒 * */public class ImageUtil { /** * 設置水印圖片在左上角 * @param Context * @param src * @param watermark * @param paddingLeft * @param paddingTop * @return */ public static Bitmap createWaterMaskLeftTop( Context context, Bitmap src, Bitmap watermark, int paddingLeft, int paddingTop) { return createWaterMaskBitmap(src, watermark, dp2px(context, paddingLeft), dp2px(context, paddingTop)); } 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(); //創(chuàng)建一個bitmap Bitmap newb = Bitmap.createBitmap(width, height, Config.ARGB_8888);// 創(chuàng)建一個新的和SRC長度寬度一樣的位圖 //將該圖片作為畫布 Canvas canvas = new Canvas(newb); //在畫布 0，0坐標上開始繪制原始圖片 canvas.drawBitmap(src, 0, 0, null); //在畫布上繪制水印圖片 canvas.drawBitmap(watermark, paddingLeft, paddingTop, null); // 保存 canvas.save(Canvas.ALL_SAVE_FLAG); // 存儲 canvas.restore(); return newb; } /** * 設置水印圖片在右下角 * @param Context * @param src * @param watermark * @param paddingRight * @param paddingBottom * @return */ public static Bitmap createWaterMaskRightBottom( Context context, Bitmap src, Bitmap watermark, int paddingRight, int paddingBottom) { return createWaterMaskBitmap(src, watermark, src.getWidth() - watermark.getWidth() - dp2px(context, paddingRight), src.getHeight() - watermark.getHeight() - dp2px(context, paddingBottom)); } /** * 設置水印圖片到右上角 * @param Context * @param src * @param watermark * @param paddingRight * @param paddingTop * @return */ public static Bitmap createWaterMaskRightTop( Context context, Bitmap src, Bitmap watermark, int paddingRight, int paddingTop) { return createWaterMaskBitmap( src, watermark, src.getWidth() - watermark.getWidth() - dp2px(context, paddingRight), dp2px(context, paddingTop)); } /** * 設置水印圖片到左下角 * @param Context * @param src * @param watermark * @param paddingLeft * @param paddingBottom * @return */ public static Bitmap createWaterMaskLeftBottom( Context context, Bitmap src, Bitmap watermark, int paddingLeft, int paddingBottom) { return createWaterMaskBitmap(src, watermark, dp2px(context, paddingLeft), src.getHeight() - watermark.getHeight() - dp2px(context, paddingBottom)); } /** * 設置水印圖片到中間 * @param Context * @param src * @param watermark * @return */ public static Bitmap createWaterMaskCenter(Bitmap src, Bitmap watermark) { return createWaterMaskBitmap(src, watermark, (src.getWidth() - watermark.getWidth()) / 2, (src.getHeight() - watermark.getHeight()) / 2); } /** * 給圖片添加文字到左上角 * @param context * @param bitmap * @param text * @return */ public static Bitmap drawTextToLeftTop(Context context, Bitmap bitmap, String text, int size, int color, int paddingLeft, int paddingTop) { 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, paint, bounds, dp2px(context, paddingLeft), dp2px(context, paddingTop) + bounds.height()); } /** * 繪制文字到右下角 * @param context * @param bitmap * @param text * @param size * @param color * @param paddingLeft * @param paddingTop * @return */ public static Bitmap drawTextToRightBottom(Context context, Bitmap bitmap, String text, 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, paint, bounds, bitmap.getWidth() - bounds.width() - dp2px(context, paddingRight), bitmap.getHeight() - dp2px(context, paddingBottom)); } /** * 繪制文字到右上方 * @param context * @param bitmap * @param text * @param size * @param color * @param paddingRight * @param paddingTop * @return */ public static Bitmap drawTextToRightTop(Context context, Bitmap bitmap, String text, int size, int color, int paddingRight, int paddingTop) { 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, paint, bounds, bitmap.getWidth() - bounds.width() - dp2px(context, paddingRight), dp2px(context, paddingTop) + bounds.height()); } /** * 繪制文字到左下方 * @param context * @param bitmap * @param text * @param size * @param color * @param paddingLeft * @param paddingBottom * @return */ public static Bitmap drawTextToLeftBottom(Context context, Bitmap bitmap, String text, int size, int color, int paddingLeft, 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, paint, bounds, dp2px(context, paddingLeft), bitmap.getHeight() - dp2px(context, paddingBottom)); } /** * 繪制文字到中間 * @param context * @param bitmap * @param text * @param size * @param color * @return */ public static Bitmap drawTextToCenter(Context context, Bitmap bitmap, String text, int size, int color) { 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, paint, bounds, (bitmap.getWidth() - bounds.width()) / 2, (bitmap.getHeight() + bounds.height()) / 2); } //圖片上繪制文字 private static Bitmap drawTextToBitmap(Context context, Bitmap bitmap, String text, Paint paint, Rect bounds, int paddingLeft, int paddingTop) { android/168375.html">android/212432.html">android.graphics.Bitmap.Config bitmapConfig = bitmap.getConfig(); paint.setDither(true); // 獲取跟清晰的圖像采樣 paint.setFilterBitmap(true);// 過濾一些 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); return bitmap; } /** * 縮放圖片 * @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 { // 記錄src的寬高 int width = src.getWidth(); int height = src.getHeight(); // 創(chuàng)建一個matrix容器 Matrix matrix = new Matrix(); // 計算縮放比例 float scaleWidth = (float) (w / width); float scaleHeight = (float) (h / height); // 開始縮放 matrix.postScale(scaleWidth, scaleHeight); // 創(chuàng)建縮放后的圖片 return Bitmap.createBitmap(src, 0, 0, width, height, matrix, true); } } /** * dip轉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); } }使用方法如下：
添加一個布局，上面是原始圖片，下面是添加水印后的圖片
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <TextView android:id="@+id/sour_pic_title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="原圖" /> <ImageView android:id="@+id/sour_pic" android:layout_width="match_parent" android:layout_height="wrap_content" android:scaleType="centerInside"/> <TextView android:id="@+id/watermark_pic_title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="水印" /> <ImageView android:id="@+id/wartermark_pic" android:layout_width="match_parent" android:layout_height="wrap_content" android:scaleType="centerInside"/></LinearLayout>
在Activity中獲取到ImageView對象，并且獲取Bitmap對象，對Bitmap進行canva繪圖，添加水印：
/** * 圖片工具類 * @author 水寒 * */public class MainActivity extends Activity { private ImageView mSourImage; private ImageView mWartermarkImage; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView(); } private void initView(){ mSourImage = (ImageView) findViewById(R.id.sour_pic); mWartermarkImage = (ImageView) findViewById(R.id.wartermark_pic); Bitmap sourBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.sour_pic); mSourImage.setImageBitmap(sourBitmap); Bitmap waterBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.weixin); Bitmap watermarkBitmap = ImageUtil.createWaterMaskCenter(sourBitmap, waterBitmap); watermarkBitmap = ImageUtil.createWaterMaskLeftBottom(this, watermarkBitmap, waterBitmap, 0, 0); watermarkBitmap = ImageUtil.createWaterMaskRightBottom(this, watermarkBitmap, waterBitmap, 0, 0); watermarkBitmap = ImageUtil.createWaterMaskLeftTop(this, watermarkBitmap, waterBitmap, 0, 0); watermarkBitmap = ImageUtil.createWaterMaskRightTop(this, watermarkBitmap, waterBitmap, 0, 0); Bitmap textBitmap = ImageUtil.drawTextToLeftTop(this, watermarkBitmap, "左上角", 16, Color.RED, 0, 0); textBitmap = ImageUtil.drawTextToRightBottom(this, textBitmap, "右下角", 16, Color.RED, 0, 0); textBitmap = ImageUtil.drawTextToRightTop(this, textBitmap, "右上角", 16, Color.RED, 0, 0); textBitmap = ImageUtil.drawTextToLeftBottom(this, textBitmap, "左下角", 16, Color.RED, 0, 0); textBitmap = ImageUtil.drawTextToCenter(this, textBitmap, "中間", 16, Color.RED); mWartermarkImage.setImageBitmap(textBitmap); }}以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持VEVB武林網。
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