Android Bitmap & Paint & Canvas & Matrix 位图/图片/画板

Bitmap & Paint & Canvas & Matrix 位图/图片/画板

加载图片

//创建一个位图工厂的配置文件
BitmapFactory.Options options = new BitmapFactory.Options();
//配置解码器不去真正解析图片，去获取图片的高宽信息
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile("/mnt/sdcard/pic/jpg",options);
//获取图片的高宽信息
int imgWidth = options.outWidth;
int imgHeight = options.outHeight;
//计算缩放比例
int scale = 1;
int scaleX = imgWidth/witdh; //witdh屏幕或界面宽度
int scaleY = imgHeight/height;
if(scaleX>=scaleY && scaleX>scale) scale = scaleX;
if(scaleY>scaleX && scaleY>scale) scale = scaleY;
//配置缩放比, 取消之前的不解析图片 并 按照缩放比加载图片
options.inSampleSize = scale;
options.inJustDecodeBounds = false;
Bitmap bitmap = BitmapFactory.decodeFile("/mnt/sdcard/pic/jpg", options);
//把图片装载控件
img0.setImageBitmap(bitmap);

Paint 画笔

Paint paint1 = new Paint();
paint1.setColor(Color.WHITE);        // 画笔颜色
paint1.setAntiAlias(true);           // 启用抗锯齿 会变慢
paint1.setDither(true);              // 启用抖动处理 更美观
paint1.setStyle(Paint.Style.STROKE); // 设置画笔为空心
paint2.setAlpha(50);                 // 透明度
paint1.setStrokeWidth((float) 2);    // 设置线宽
paint4.setTextSize(this.Scale / 3);  //画的文本大小

Canvas 画板

canvas.drawColor(Color.BLACK); // 设置画布背景颜色
canvas.drawLine(GoX, GoY, ToX, ToY, paint); //划线
canvas.drawText("我爱你", startX, startY, paint); //写字 startX/Y左上角坐标

画画

//通过位图工厂获取图片
final Bitmap srcBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.pic00);
//获取原图的副本 相同尺寸的空白纸
final Bitmap copyBitmap = Bitmap.createBitmap(srcBitmap.getWidth(),srcBitmap.getHeight(),srcBitmap.getConfig());
final Paint paint = new Paint(); //创建画笔
final Canvas canvas = new Canvas(copyBitmap); //创建画板
canvas.drawBitmap(srcBitmap, new Matrix(), paint); //把原图画上去

paint.setColor(Color.RED); // 画笔颜色
paint.setStrokeWidth((float) 50); // 设置线宽

myImg.setImageBitmap(copyBitmap); //设置图片
myImg.setOnTouchListener(new OnTouchListener() { //设置触摸事件
float startX = 0;
float startY = 0;
float stopX = 0;
float stopY = 0;

@Override
public boolean onTouch(View v, MotionEvent event) {

switch (event.getAction()) {
case MotionEvent.ACTION_DOWN: //按下
Log.e("***************", event.getX()+"-"+event.getY());
//获取开始坐标
startX = event.getX();
startY = event.getY();
break;

case MotionEvent.ACTION_MOVE: //移动
//获取结束坐标
stopX = event.getX();
stopY = event.getY();

//画线
canvas.drawLine(startX*2, startY, stopX*2, stopY, paint);

//重新设置开始坐标
startX = stopX;
startY = stopY;
//重新加载图片
myImg.setImageBitmap(copyBitmap);
break;

case MotionEvent.ACTION_UP: //抬起
break;

default:
break;
}

return true;
}
});

canvas.drawBitmap(srcBitmap, new Matrix(), paint); //把原图画上去
myImg.setImageBitmap(copyBitmap);

private void drawYTable(Canvas canvas, Paint paint) {

Path path = new Path();

PathEffect pathEffect = new DashPathEffect(new float[] { 5, 2 }, 1);

paint.setPathEffect(pathEffect);

// Y向线
// (*/2:因为间距是20，我要以10画一条线)
for (int i = 1; i < yLabel.length * 2 - 1; i++) {
float startY = yPoint - i * Scale / 2;
float stopX = xPoint + (this.xLabel.length ) * Scale - Scale/2;

path.moveTo(xPoint, startY);
path.lineTo(stopX, startY);

canvas.drawPath(path, paint);
}
}

操作图片

Matrix matrix = new Matrix();
//每次操作都会覆盖原先的操作
matrix.setRotate(20, srcBitmap.getWidth()/2, srcBitmap.getHeight()/2); //旋转
matrix.setScale(0.5f, 0.5f); //切换大小
matrix.setTranslate(30, 0); //平移
//镜面效果
matrix.setScale(-1.0f, 1);
matrix.postTranslate(srcBitmap.getWidth(), 0); //post 在上次修改的基础上再进行修改
//倒影效果
matrix.setScale(1.0f, -1);
matrix.postTranslate(0, srcBitmap.getWidth());

//应用修改
canvas.drawBitmap(srcBitmap, matrix, paint); //把原图画上去

保存图片

try {
File file = new File(Environment.getExternalStorageDirectory().getPath(),SystemClock.uptimeMillis()+".jpg"); //开机运行了多久时间
FileOutputStream fos = new FileOutputStream(file);
copyBitmap.compress(CompressFormat.JPEG, 100, fos); //保存的类型，质量(0~100)，流

//发送一条广播 SD卡重新挂载 更新图库
Intent intent = new Intent();
intent.setAction(Intent.ACTION_MEDIA_MOUNTED);
intent.setData(Uri.fromFile(Environment.getExternalStorageDirectory()));
sendBroadcast(intent);

Toast.makeText(getApplicationContext(), "保存成功", 0).show();
} catch (Exception e) {
e.printStackTrace();
}

撕衣服

img.setOnTouchListener(new OnTouchListener() {

@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
break;
case MotionEvent.ACTION_MOVE:
try {
for(int x=-20; x<20; ++x)
for(int y=-20; y<20; ++y){
if(Math.sqrt(x*x+y*y)<20) //改为圆
copyBitmap.setPixel((int)event.getX()+x,(int)event.getY()+y,Color.TRANSPARENT); //Color.TRANSPARENT透明
}
img.setImageBitmap(copyBitmap); //设置图片
} catch (Exception e) {
e.printStackTrace();
}
break;

default:
break;
}
return true;
}
});