Android给图片加文字和图片水印实例代码

我们在做项目的时候有时候需要给图片添加水印，水寒今天就遇到了这样的问题，所以搞了一个工具类，贴出来大家直接调用就行。

/**
* 图片工具类
* @author 水寒
*
*/
public class ImageUtil {
/**
* 设置水印图片在左上角
* @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();
//创建一个bitmap
Bitmap newb = Bitmap.createBitmap(width, height, 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;
}
/**
* 设置水印图片在右下角
* @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));
}
/**
* 设置水印图片到右上角
* @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));
}
/**
* 设置水印图片到左下角
* @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));
}
/**
* 设置水印图片到中间
* @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);
}
/**
* 给图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());
}
/**
* 绘制文字到右下角
* @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));
}
/**
* 绘制文字到右上方
* @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());
}
/**
* 绘制文字到左下方
* @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));
}
/**
* 绘制文字到中间
* @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);
}
//图片上绘制文字
private static Bitmap drawTextToBitmap(Context context, Bitmap bitmap, String text,
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);
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);
}
}

使用方法如下：

添加一个布局，上面是原始图片，下面是添加水印后的图片

<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="原图" />
<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中获取到ImageView对象，并且获取Bitmap对象，对Bitmap进行canva绘图，添加水印：

/**
* 图片工具类
* @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, "中间", 16, Color.RED);
mWartermarkImage.setImageBitmap(textBitmap);
}
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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