使用Canvas从头开始创建一个形状(例如带有阴影的矩形)需要哪些步骤?
在绘制矩形的油漆上添加阴影层没有成功。
不需要位图,只需要将层类型设置为LAYER_TYPE_SOFTWARE
,原始方法就可以了。
public class TestShapeShadow extends View
{
Paint paint;
public TestShapeShadow(Context context)
{
super(context);
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setShadowLayer(12, 0, 0, Color.YELLOW);
// Important for certain APIs
setLayerType(LAYER_TYPE_SOFTWARE, paint);
}
@Override
protected void onDraw(Canvas canvas)
{
canvas.drawRect(20, 20, 100, 100, paint);
}
}
我遵循@pskink答案中的想法,找到了解决方案。我把代码片段放在这里,供任何需要的人使用。
public class MyViewWithShadow extends View {
Paint paint;
int mainColor;
int shadowColor;
// shadow properties
int offsetX = -25;
int offsetY = 30;
int blurRadius = 5;
public MyViewWithShadow(Context context)
{
super(context);
mainColor = Color.RED;
shadowColor = Color.BLACK; // this color can also have alpha
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setStyle(Paint.Style.FILL);
}
@Override
protected void onDraw(Canvas canvas)
{
// Create paint for shadow
paint.setColor(shadowColor);
paint.setMaskFilter(new BlurMaskFilter(
blurRadius /* shadowRadius */,
BlurMaskFilter.Blur.NORMAL));
// Draw shadow before drawing object
canvas.drawRect(20 + offsetX, 20 + offsetY, 100 + offsetX, 100 + offsetY, paint);
// Create paint for main object
paint.setColor(mainColor);
paint.setMaskFilter(null);
// Draw main object
canvas.drawRect(20, 20, 100, 100, paint);
}
}
[链接现已断开:]
如果你想知道阴影属性是什么,你可以参考这个测试仪:https://okawa-h.github.io/box-shadow_tester/~
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创建。a路径,添加一些元素到
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将BlurMaskFilter设置为Paint
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用dx,dy阴影偏移绘制路径
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未设置掩码过滤器
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用无偏移再次绘制路径