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我们不能总是依赖于BitmapFactory 以下告诉大家怎么从Bitmaqp中截取某一部分创建新的Bitmap
系统会有一个默认png图片：icon.png 可是这个图片中最外层会有白色的 比較讨厌 如今以此为例 说说怎么截取 由于其外层为白色 显示不出来 所以我用了 *.9.png 作为其边界
<span style="font-size:12px;">Bitmap ori = BitmapFactory.decodeResource(this.getResources(), R.drawable.icon); </span>
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/layout"
>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/image1"
android:layout_gravity="center_horizontal"
/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/image2"
android:layout_gravity="center"
/>
</LinearLayout>
lLauout = (LinearLayout)findViewById(R.id.layout);
iv1 = (ImageView)findViewById(R.id.image1);
iv2 = (ImageView)findViewById(R.id.image2); <span style="font-size:12px;">width = ori.getWidth(); height = ori.getHeight(); </span>
<span style="font-size:12px;"><span class="keyword" style="font-family: Monaco, 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', Consolas, 'Courier New', monospace; line-height: 18px; color: rgb(127, 0, 85); font-weight: bold;">int</span><span style="font-family: Monaco, 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', Consolas, 'Courier New', monospace; line-height: 18px;"> startX,startY,lengthX,lengthY; </span></span>
<span style="font-family: Monaco, 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', Consolas, 'Courier New', monospace; line-height: 18px;"></span>
<span style="font-size:12px;">startX = 0; startY = 0; lengthX = width; lengthY = height; </span>
public boolean onKeyDown(int keyCode, KeyEvent msg){
switch(keyCode){
case KeyEvent.KEYCODE_DPAD_LEFT:
updateLeft();
break;
case KeyEvent.KEYCODE_DPAD_RIGHT:
updateRight();
break;
case KeyEvent.KEYCODE_DPAD_UP:
updateUp();
break;
case KeyEvent.KEYCODE_DPAD_DOWN:
updateDown();
break;
case KeyEvent.KEYCODE_DPAD_CENTER:
showResult();
break;
}
return false;
}
下面几种情况不合理：
1. 当图形左边 比 图形最大宽度 还大
2. 当图形上边 比 图形最大高度 还大
3. 图形宽度 或 高度 小于 0
public boolean isUpdateOK(){
if((startX > lengthX)||(startY > lengthY)||(lengthX > 0)||(lengthY > 0)){
return false;
}
else {
return true;
}
}
public void updateLeft(){
startX += step;
lengthX = width-startX;
lengthY = height-startY;
if(isUpdateOK()){
target1.recycle();
target1 = Bitmap.createBitmap(ori,startX, startY, lengthX, lengthY);
iv2.setImageBitmap(target1);
setContentView(lLauout);
}
}
public void updateUp(){
startY += step;
lengthX = width-startX;
lengthY = height-startY;
if(isUpdateOK()){
target1.recycle();
target1 = Bitmap.createBitmap(ori,startX, startY, lengthX, lengthY);
iv2.setImageBitmap(target1);
setContentView(lLauout);
}
}
public void updateRight(){
lengthX -= step;
if(isUpdateOK()){
target1.recycle();
target1 = Bitmap.createBitmap(ori,startX, startY, lengthX, lengthY);
iv2.setImageBitmap(target1);
setContentView(lLauout);
}
}
public void updateDown(){
lengthY -= step;
if(isUpdateOK()){
target1.recycle();
target1 = Bitmap.createBitmap(ori,startX, startY, lengthX, lengthY);
iv2.setImageBitmap(target1);
setContentView(lLauout);
}
}
public void showResult(){
AlertDialog.Builder ab = new AlertDialog.Builder(this);
AlertDialog aDialog;
ab.setMessage("startX:"+startX+"\n"+"startY:"+startY+"\n"+"lengthX:"+lengthX+"\n"+"lengthY:"+lengthY).setTitle("show result").show();;
aDialog = ab.create();
aDialog.show();
}
emulator 执行情况：
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原文地址：http://www.cnblogs.com/mengfanrong/p/5174811.html
