android_64_drawBitmap_canvas_matrix

效果:

平移:



缩放:



旋转:



镜面:



倒影:



清单:(权限)

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.sg31.drawbitmap"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />

// 权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>

</manifest>


布局:

<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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.sg31.drawbitmap.MainActivity"
android:orientation="vertical"
>

<ImageView
android:id="@+id/iv_src"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<ImageView
android:id="@+id/iv_copy"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>

</LinearLayout>

代码:

package com.sg31.drawbitmap;

import android.support.v7.app.ActionBarActivity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ImageView;

public class MainActivity extends ActionBarActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

drawBitmap();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}

public void drawBitmap() {
// 这个对象是只读的
Bitmap bmSrc = BitmapFactory.decodeFile("sdcard/sg.jpeg");

// 创建图片副本
// 1.在内存中创建一个与原图一模一样大小的bitmap对象，创建与原图大小一致的白纸
Bitmap bmCopy = Bitmap.createBitmap(bmSrc.getWidth(),
bmSrc.getHeight(), bmSrc.getConfig());

// 2.创建画笔对象
Paint paint = new Paint();

// 3.创建画板对象，把白纸铺在画板上
Canvas canvas = new Canvas(bmCopy);

// 4.开始作画，把原图的内容绘制在白纸上
Matrix mt = new Matrix();

// 平移
mt.setTranslate(20, 40);

// 缩放
// sx：水平方向的缩放比例
// sy：竖直方向的缩放比例
// mt.setScale(0.5f, 0.5f);
// mt.setScale(0.5f, 0.5f, bmCopy.getWidth() / 2, bmCopy.getHeight() /
// 2);

// 旋转
// mt.setRotate(45, bmCopy.getWidth() / 2, bmCopy.getHeight() / 2);

// 镜面
// mt.setScale(-1, 1);
// mt.postTranslate(bmCopy.getWidth(), 0);

// 倒影
// mt.setScale(1, -1);
// mt.postTranslate(0, bmCopy.getHeight());
canvas.drawBitmap(bmSrc, mt, paint);

ImageView iv_src = (ImageView) findViewById(R.id.iv_src);
ImageView iv_copy = (ImageView) findViewById(R.id.iv_copy);
iv_src.setImageBitmap(bmSrc);
iv_copy.setImageBitmap(bmCopy);
}
}