android畫圖抗鋸齒的幾個方法
阿新 • • 發佈:2019-01-25
在畫圖的時候,圖片如果旋轉或縮放之後,總是會出現那些華麗的鋸齒。其實Android自帶了解決方式。
方法一:給Paint加上抗鋸齒標誌。然後將Paint物件作為引數傳給canvas的繪製方法。
Java程式碼
paint.setAntiAlias(true);
方法二:給Canvas加上抗鋸齒標誌。
有些地方不能用paint的,就直接給canvas加抗鋸齒,更方便。
Java程式碼
canvas.setDrawFilter(new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG|Paint.FILTER_BITMAP_FLAG));
測試程式碼如下:
Java程式碼
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.graphics.PaintFlagsDrawFilter;
import android.view.View;
public class MyView extends View {
private PaintFlagsDrawFilter pfd;
private Paint mPaint = new Paint();
private Matrix matrix = new Matrix();;
private Bitmap bmp;
public MyView(Context context) {
super(context);
initialize();
}
private void initialize() {
pfd = new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG|Paint.FILTER_BITMAP_FLAG);
mPaint.setAntiAlias(true);
matrix.setRotate(30);
matrix.postScale(0.5f, 0.5f);
bmp = BitmapFactory.decodeResource(getResources(), R.drawable.show);
}
@Override
public void dispatchDraw(Canvas canvas) {
canvas.translate(100, 0);
canvas.drawBitmap(bmp, matrix, null);
canvas.translate(0, 250);
canvas.drawBitmap(bmp, matrix, mPaint);
canvas.setDrawFilter(pfd);
canvas.translate(0, 250);
canvas.drawBitmap(bmp, matrix, null);
}
}
下圖是效果:
可以看出,兩種方式都挺有效的。