我正在尝试以编程方式创建一个Bitmap,并且发现绘制一个阴影的Rect忽略了传入的颜色arg。我简化了这种情况 - 代码只是绘制了一个旋转的蓝色方块,应该有一个灰色的阴影,但阴影总是蓝色的:
main.xml:
<?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:background="#fff"
android:padding="40dp"
>
</LinearLayout>
RotateRectShadowActivity.java:
public class RotateRectShadowActivity extends Activity {
private LinearLayout mMainLayout;
private ImageView mImageView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LayoutInflater factory = LayoutInflater.from( this );
mMainLayout = (LinearLayout) factory.inflate( R.layout.main, null );
mImageView = new ImageView(this);
Rect rect = new Rect(0, 0, 300, 300);
Bitmap outerBm = Bitmap.createBitmap(
rect.width(), rect.height(), Bitmap.Config.ARGB_8888);
Bitmap innerBm = Bitmap.createBitmap(
rect.width()-50, rect.height()-50, Bitmap.Config.ARGB_8888);
Canvas outerCanvas = new Canvas(outerBm);
Canvas innerCanvas = new Canvas(innerBm);
outerCanvas.rotate(3);
rect.left += 25;
rect.top += 25;
rect.right += 25;
rect.bottom += 25;
Paint shadowPaint = new Paint();
shadowPaint.setShadowLayer(12, 12, 12, 0xFF555555);
shadowPaint.setColor(0xFF555555);
innerCanvas.drawRect(rect, shadowPaint);
Paint rectPaint = new Paint();
rectPaint.setColor(Color.BLUE);
innerCanvas.drawRect(rect, rectPaint);
outerCanvas.drawBitmap(innerBm, 0, 0, shadowPaint);
mImageView.setImageBitmap(outerBm);
mMainLayout.addView(mImageView);
setContentView(mMainLayout);
}
}
我不明白为什么调用outerCanvas.drawBitmap(innerBm,0,0,shadowPaint);需要一个Paint,因为我试图通过innerCanvas在innerBm上绘制阴影,但是当我传递null时,根本就没有阴影。
答案 0 :(得分:4)
您的内部位图太小了,它会切割矩形的边缘。试试这个:
Bitmap outerBm = Bitmap.createBitmap(
rect.width(), rect.height(), Bitmap.Config.ARGB_8888);
Bitmap innerBm = Bitmap.createBitmap(
rect.width() + 50, rect.height() + 50, Bitmap.Config.ARGB_8888);
Canvas outerCanvas = new Canvas(outerBm);
Canvas innerCanvas = new Canvas(innerBm);
outerCanvas.rotate(3);
rect.left += 25;
rect.top += 25;
rect.right -= 25;
rect.bottom -= 25;
Paint shadowPaint = new Paint();
shadowPaint.setColor(Color.BLUE);;
shadowPaint.setShadowLayer(12, 12, 12, 0xFF555555);
innerCanvas.drawRect(rect, shadowPaint);
outerCanvas.drawBitmap(innerBm, 0, 0, null);