用android来实现图片的绘制以及旋转缩放案例分析

在这点上Android 确实比J2ME 强大很多 手机游戏开发最痛苦的是什么？？ 是游戏引擎的开发，但是工程师会把大部分时间浪费在对坐标上，如果写引擎的时候没有把自适应考虑周全后期会非常痛苦，现在手机屏幕分辨率是各式各样 内存大小也是各式各样 所以可见自适应屏幕算法有多么的重要。

package cn.m15.xys;

import android.app.Activity;
import android.content.Context;
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.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.LinearLayout;

public class Image extends Activity {
ImageView imageView = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
imageView = new ImageView(this);
setContentView(R.layout.image);
LinearLayout ll = (LinearLayout) findViewById(R.id.iamgeid);
ll.addView(imageView);
// 向左移动
Button botton0 = (Button) findViewById(R.id.buttonLeft);
botton0.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
imageView.setPosLeft();
}
});

// 向右移动
Button botton1 = (Button) findViewById(R.id.buttonRight);
botton1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
imageView.setPosRight();
}
});
// 左旋转
Button botton2 = (Button) findViewById(R.id.buttonRotationLeft);
botton2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
imageView.setRotationLeft();
}
});

// 右旋转
Button botton3 = (Button) findViewById(R.id.buttonRotationRight);
botton3.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
imageView.setRotationRight();
}
});

// 缩小
Button botton4 = (Button) findViewById(R.id.buttonNarrow);
botton4.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View arg0) {
imageView.setNarrow();
}
});

// 放大
Button botton5 = (Button) findViewById(R.id.buttonEnlarge);
botton5.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View arg0) {
imageView.setEnlarge();
}
});

super.onCreate(savedInstanceState);

}

class ImageView extends View {
Paint mPaint = null;
Bitmap bitMap = null;
Bitmap bitMapDisplay = null;
int m_posX = 120;
int m_posY = 50;
int m_bitMapWidth = 0;
int m_bitMapHeight = 0;
Matrix mMatrix = null;
float mAngle = 0.0f;
float mScale = 1f;//1为原图的大小

public ImageView(Context context) {
super(context);
mPaint = new Paint();
mPaint.setFlags(Paint.ANTI_ALIAS_FLAG);
bitMap = BitmapFactory.decodeResource(this.getResources(),
R.drawable.image);
bitMapDisplay = bitMap;
mMatrix = new Matrix();
// 获取图片宽高
m_bitMapWidth = bitMap.getWidth();
m_bitMapHeight = bitMap.getHeight();
}

// 向左移动
public void setPosLeft() {
m_posX -= 10;
}

// 向右移动
public void setPosRight() {
m_posX += 10;
}

// 向左旋转
public void setRotationLeft() {
mAngle--;
setAngle();
}

// 向右旋转
public void setRotationRight() {
mAngle++;
setAngle();
}

// 缩小图片
public void setNarrow() {
if (mScale > 0.5) {
mScale -= 0.1;
setScale();
}
}

// 放大图片
public void setEnlarge() {
if (mScale < 2) {
mScale += 0.1;
setScale();
}
}

// 设置缩放比例
public void setAngle() {
mMatrix.reset();
mMatrix.setRotate(mAngle);
bitMapDisplay = Bitmap.createBitmap(bitMap, 0, 0, m_bitMapWidth,
m_bitMapHeight, mMatrix, true);
}

// 设置旋转比例
public void setScale() {
mMatrix.reset();
//float sx X轴缩放
//float sy Y轴缩放
mMatrix.postScale(mScale, mScale);
bitMapDisplay = Bitmap.createBitmap(bitMap, 0, 0, m_bitMapWidth,
m_bitMapHeight, mMatrix, true);
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawBitmap(bitMapDisplay, m_posX, m_posY, mPaint);
invalidate();
}
}
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/iamgeid"
androidrientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<Button android:id="@+id/buttonLeft"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:text="图片向左移动"
/>
<Button android:id="@+id/buttonRight"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:text="图片向右移动"
/>
<Button android:id="@+id/buttonRotationLeft"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:text="图片左旋转"
/>
<Button android:id="@+id/buttonRotationRight"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:text="图片右旋转"
/>
<Button android:id="@+id/buttonNarrow"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:text="图片缩小"
/>
<Button android:id="@+id/buttonEnlarge"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:text="图片放大"
/>
</LinearLayout>