如何将图像放置到画布上以便在该图像上进行绘制?
在画布上绘制Drawable的好方法不是自己解码,而是让系统来完成:
Drawable d = getResources().getDrawable(R.drawable.foobar, null);
d.setBounds(left, top, right, bottom);
d.draw(canvas);
这将适用于所有类型的drawable,不仅限于位图。这还意味着,如果只有大小发生变化,您也可以再次重复使用相同的drawable。
您需要将图像作为位图加载:
Resources res = getResources();
Bitmap bitmap = BitmapFactory.decodeResource(res, R.drawable.your_image);
然后将位图变为可变的,并在其上创建一个画布:
Canvas canvas = new Canvas(bitmap.copy(Bitmap.Config.ARGB_8888, true));
然后你可以在画布上绘制。
你也可以使用这种方法。它将使您的大绘图适应您的画布:
Resources res = getResources();
Bitmap bitmap = BitmapFactory.decodeResource(res, yourDrawable);
yourCanvas.drawBitmap(bitmap, 0, 0, yourPaint);
yourDrawable
是一个整数。 - user6754053Drawable d = ContextCompat.getDrawable(context, R.drawable.***)
d.setBounds(left, top, right, bottom);
d.draw(canvas);
setBounds
是必要的。如果没有它,什么都不会显示出来。 - user6754053试一下这个
Bitmap mBitmap = Bitmap.createScaledBitmap(Bitmap src, int dstWidth, int dstHeight, boolean filter);
protected void onDraw(Canvas canvas) {
canvas.drawColor(0xFFAAAAAA);
canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
}
val drawable = resources.getDrawable(R.drawable.my_vector, null)
val aspectRatio = drawable.intrinsicWidth.toFloat() / drawable.intrinsicHeight
val desiredWidthInPx = 100
val derivedHeightInPx = (desiredWidthInPx / aspectRatio).toInt()
drawable.setBounds(0, 0, desiredWidthInPx, derivedHeightInPx)
drawable.draw(canvas)
package com.android.jigsawtest;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class SurafaceClass extends SurfaceView implements
SurfaceHolder.Callback {
Bitmap mBitmap;
Paint paint =new Paint();
public SurafaceClass(Context context) {
super(context);
mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.icon);
// TODO Auto-generated constructor stub
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawColor(Color.BLACK);
canvas.drawBitmap(mBitmap, 0, 0, paint);
}
}
setBounds(0, 0, width, height)
- vrgrg