前一篇文章讲述了Android触屏setOnTouchListener实现突破缩放、移动、绘制和添加水印,继续我的"随手拍"项目完成给图片添加相框、圆形圆角显示图片和图像合成的功能介绍.希望文章对大家有所帮助.
首先,对XML中activity_main.xml进行布局,通过使用RelativeLayout相对布局完成(XML代码后面附).然后,在Mainctivity.java中public class MainActivity extends Activity函数添加代码如下,添加点击按钮监听事件：
//控件
private Button openImageBn; //打开图片
private Button showImageBn; //显示assets资源图片
private Button showImageBn1; //模式1加成
private Button showImageBn2; //模式2加成
private Button roundImageBn; //圆角图片
private ImageView imageShow; //显示图片
//自定义变量
private Bitmap bmp; //原始图片
private final int IMAGE_OPEN = 0; //打开图片
private Canvas canvas; //画布
private Paint paint; //画刷
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//打开图片
openImageBn = (Button)findViewById(R.id.button1);
imageShow = (ImageView) findViewById(R.id.imageView1);
openImageBn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(Intent.ACTION_PICK,
android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(intent, IMAGE_OPEN);
}
});
if (savedInstanceState == null) {
getFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
}
}
//打开图片
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(resultCode==RESULT_OK && requestCode==IMAGE_OPEN) {
Uri imageFileUri = data.getData();
DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
int width = dm.widthPixels; //手机屏幕水平分辨率
int height = dm.heightPixels; //手机屏幕垂直分辨率
try {
//载入图片尺寸大小没载入图片本身 true
BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
bmpFactoryOptions.inJustDecodeBounds = true;
bmp = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageFileUri), null, bmpFactoryOptions);
int heightRatio = (int)Math.ceil(bmpFactoryOptions.outHeight/(float)height);
int widthRatio = (int)Math.ceil(bmpFactoryOptions.outWidth/(float)width);
//inSampleSize表示图片占原图比例 1表示原图
if(heightRatio>1&&widthRatio>1) {
if(heightRatio>widthRatio) {
bmpFactoryOptions.inSampleSize = heightRatio;
}
else {
bmpFactoryOptions.inSampleSize = widthRatio;
}
}
//图像真正解码 false
bmpFactoryOptions.inJustDecodeBounds = false;
bmp = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageFileUri), null, bmpFactoryOptions);
imageShow.setImageBitmap(bmp);
}
catch(FileNotFoundException e) {
e.printStackTrace();
}
} //end if
}
上面点击"打开"按钮能实现打开图片,而在讲述为图片添加边框时,它其实就是通过两张或多张图片的合成实现的.
在jacpy.may《Android图片处理总结》文档中建议图片不要放在drawable目录下,因为屏幕分辨率会影响图片的大小.最好放在assets目录里,它代表应用无法直接访问的原生资源(通常加载PNG透明图实现边框合成),只能以流的方式读取并且小于1M.
读取assets文件夹中图片的方法如下,首先手动添加PNG图片至assets目录,然后在omCreate函数中添加如下代码：
//显示assets中图片
showImageBn = (Button)findViewById(R.id.button2);
showImageBn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Bitmap bitmap = getImageFromAssets("image01.png");
imageShow.setImageBitmap(bitmap);
}
}); 再通过自定义函数getImageFromAssets实现获取图片"image01.png"：
//获取assets中资源并转换为Bitmap
private Bitmap getImageFromAssets(String fileName)
{
//Android中使用assets目录存放资源,它代表应用无法直接访问的原生资源
Bitmap imageAssets = null;
AssetManager am = getResources().getAssets();
try {
InputStream is = am.open(fileName);
imageAssets = BitmapFactory.decodeStream(is);
is.close();
} catch(IOException e) {
e.printStackTrace();
}
return imageAssets;
} 显示效果如下图所示：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.touchimagetest.MainActivity"
tools:ignore="MergeRootFrame" >
<!-- 底部添加按钮 -->
<RelativeLayout
android:id="@+id/MyLayout_bottom"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="50dp"
android:layout_alignParentBottom="true"
android:gravity="center">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:layout_alignParentBottom="true" >
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="打开" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="显示" />
<Button
android:id="@+id/button3"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="边框" />
<Button
android:id="@+id/button4"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="桃心" />
<Button
android:id="@+id/button5"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="圆形" />
</LinearLayout>
</RelativeLayout>
<!-- 顶部显示图片 -->
<RelativeLayout
android:id="@+id/Content_Layout"
android:orientation="horizontal"
android:layout_above="@id/MyLayout_bottom"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:background="#000000"
android:gravity="center">
<ImageView
android:id="@+id/imageView1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_gravity="center_horizontal" />
</RelativeLayout>
</RelativeLayout>
//模式1合成图片
showImageBn1 = (Button)findViewById(R.id.button3);
showImageBn1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Bitmap bitmap = getImageFromAssets("image01.png");
addFrameToImage(bitmap);
}
}); 通过自定义函数addFrameToImage实现加载图片合成.首先创建一个空的可变为图对象,它的大小和配置与打开的图像相同,随后构建一个Canvas对象和一个Paint对象,在画布上绘制第一个位图对象,它成为了合成操作的目标.//图片合成1
private void addFrameToImage(Bitmap bm) //bmp原图(前景) bm资源图片(背景)
{
Bitmap drawBitmap =Bitmap.createBitmap(bmp.getWidth(),
bmp.getHeight(), bmp.getConfig());
canvas = new Canvas(drawBitmap);
paint = new Paint();
canvas.drawBitmap(bmp, 0, 0, paint);
paint.setXfermode(new PorterDuffXfermode(android.
graphics.PorterDuff.Mode.LIGHTEN));
//对边框进行缩放
int w = bm.getWidth();
int h = bm.getHeight();
//缩放比 如果图片尺寸超过边框尺寸 会自动匹配
float scaleX = bmp.getWidth()*1F / w;
float scaleY = bmp.getHeight()*1F / h;
Matrix matrix = new Matrix();
matrix.postScale(scaleX, scaleY); //缩放图片
Bitmap copyBitmap = Bitmap.createBitmap(bm, 0, 0, w, h, matrix, true);
canvas.drawBitmap(copyBitmap, 0, 0, paint);
imageShow.setImageBitmap(drawBitmap);
} 第二种方法是参照《Android多媒体开发高级编程》,但是它图片十四合成效果不是很好：//模式2合成图片
showImageBn2 = (Button)findViewById(R.id.button4);
showImageBn2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Bitmap bitmap = getImageFromAssets("image07.png");
//第二种合成方法
imageShow.setImageBitmap(addFrameToImageTwo(bitmap));
}
});
然后通过自定义函数实现：//图片合成
private Bitmap addFrameToImageTwo(Bitmap frameBitmap) //bmp原图 frameBitmap资源图片(边框)
{
//bmp原图 创建新位图
int width = bmp.getWidth();
int height = bmp.getHeight();
Bitmap drawBitmap =Bitmap.createBitmap(width, height, Config.RGB_565);
//对边框进行缩放
int w = frameBitmap.getWidth();
int h = frameBitmap.getHeight();
float scaleX = width*1F / w; //缩放比 如果图片尺寸超过边框尺寸 会自动匹配
float scaleY = height*1F / h;
Matrix matrix = new Matrix();
matrix.postScale(scaleX, scaleY); //缩放图片
Bitmap copyBitmap = Bitmap.createBitmap(frameBitmap, 0, 0, w, h, matrix, true);
int pixColor = 0;
int layColor = 0;
int newColor = 0;
int pixR = 0;
int pixG = 0;
int pixB = 0;
int pixA = 0;
int newR = 0;
int newG = 0;
int newB = 0;
int newA = 0;
int layR = 0;
int layG = 0;
int layB = 0;
int layA = 0;
float alpha = 0.8F;
float alphaR = 0F;
float alphaG = 0F;
float alphaB = 0F;
for (int i = 0; i < width; i++)
{
for (int k = 0; k < height; k++)
{
pixColor = bmp.getPixel(i, k);
layColor = copyBitmap.getPixel(i, k);
// 获取原图片的RGBA值
pixR = Color.red(pixColor);
pixG = Color.green(pixColor);
pixB = Color.blue(pixColor);
pixA = Color.alpha(pixColor);
// 获取边框图片的RGBA值
layR = Color.red(layColor);
layG = Color.green(layColor);
layB = Color.blue(layColor);
layA = Color.alpha(layColor);
// 颜色与纯黑色相近的点
if (layR < 20 && layG < 20 && layB < 20)
{
alpha = 1F;
}
else
{
alpha = 0.3F;
}
alphaR = alpha;
alphaG = alpha;
alphaB = alpha;
// 两种颜色叠加
newR = (int) (pixR * alphaR + layR * (1 - alphaR));
newG = (int) (pixG * alphaG + layG * (1 - alphaG));
newB = (int) (pixB * alphaB + layB * (1 - alphaB));
layA = (int) (pixA * alpha + layA * (1 - alpha));
// 值在0~255之间
newR = Math.min(255, Math.max(0, newR));
newG = Math.min(255, Math.max(0, newG));
newB = Math.min(255, Math.max(0, newB));
newA = Math.min(255, Math.max(0, layA));
//绘制
newColor = Color.argb(newA, newR, newG, newB);
drawBitmap.setPixel(i, k, newColor);
}
}
return drawBitmap;
} 它的运行效果如下所示,其中前2附图是方法一,但是它的合成效果不是很优秀,而第三张图是第二种方法,但是它的响应时间稍微要长些.
//圆角合成图片
roundImageBn = (Button)findViewById(R.id.button5);
roundImageBn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
imageShow.setImageBitmap(getRoundedCornerBitmap(bmp) );
}
}); 然后通过自定义函数getRoundedCornerBitmap实现圆形：//生成圆角图片
private Bitmap getRoundedCornerBitmap(Bitmap bitmap)
{
Bitmap roundBitmap = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(roundBitmap);
int color = 0xff424242;
Paint paint = new Paint();
//设置圆形半径
int radius;
if(bitmap.getWidth()>bitmap.getHeight()) {
radius = bitmap.getHeight()/2;
}
else {
radius = bitmap.getWidth()/2;
}
//绘制圆形
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawCircle( bitmap.getWidth()/ 2, bitmap.getHeight() / 2, radius, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, 0, 0, paint);
return roundBitmap;
} 同样,如果把该函数里面内容替换即可实现圆形矩形显示图片：private Bitmap getRoundedCornerBitmap(Bitmap bitmap)
{
//绘制圆角矩形
Bitmap roundBitmap = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(roundBitmap);
int color = 0xff424242;
Paint paint = new Paint();
Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
RectF rectF = new RectF(rect);
float roundPx = 80; //转角设置80
//绘制
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
} 运行结果如下图所示：
[Android] 给图像添加相框、圆形圆角显示图片、图像合成知识
原文地址：http://blog.csdn.net/eastmount/article/details/40627599
