来自另一个资源的位图绘制 [英] Draw bitmaps from resources over another

问题描述

我有两个位图的背景的和的前景的。我如何借鉴背景位图的前景，而不使用其他画布？

I have got two bitmaps, background and foreground. How do I draw bitmap foreground on background without using another Canvas?

解决方案：

1）首先创建一个额外的选项ARGB_8888从位图资源

1) First create bitmaps from resources with additional option ARGB_8888

BitmapFactory.Options options = new BitmapFactory.Options();  
options.inPreferredConfig = Bitmap.Config.ARGB_8888;

2）声明位图

Bitmap background = BitmapFactory.decodeResource(getResources(), R.drawable.background, options);  
Bitmap foreground = BitmapFactory.decodeResource(getResources(), R.drawable.foreground, options);

3）内部的onDraw（）函数绘制图形

3) Inside onDraw() function draw graphics

protected void onDraw(Canvas canvas)    
{  
    canvas.drawColor(Color.White);

    Paint paint = new Paint();
    canvas.drawBitmap(background, 0, 0, paint);
    paint.setXfermode( new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER));
    canvas.drawBitmap(foreground, 0, 0, paint); 
}

和作为Soxxeh说，这是信息的很好来源：<一个href=\"http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/graphics/Xfermodes.html\" rel=\"nofollow\">http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/graphics/Xfermodes.html

And as Soxxeh said, this is very good source of information: http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/graphics/Xfermodes.html

推荐答案

试试这个：

canvas.drawBitmap(backgroundImageBitmap, 0.0f, 0.0f, null);
canvas.drawBitmap(foregroundImageBitmap, 0.0f, 0.0f, null);

第二个图像（前景图像）都有阿尔法方面或您无法通过它看到的。

The second image (foreground image) has to have Alpha aspects or you can't see through it.

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