在动态壁纸中设置背景位图
我刚刚开始写动态壁纸。
我想做的是将背景设置为我的资源中的位图。我将在此之上绘制我的动画。
做到这一点最有效的方法是什么？有没有办法将背景设置为动态壁纸中的位图？我是否只需要每次在绘制动画之前将位图绘制到画布中（这似乎效率低得可怕）？
谢谢，
杰伊
I just started writing a live wallpaper.
What I would like to do is to set the background to a bitmap from my resources. And I will draw my animations on top of this.
What is the most efficient way to do this? Is there a way to set the background to a bitmap in a live wallpaper? Do I just need to draw the bitmap into the canvas each time before I draw my animations (which seems like it might be hideously inefficient)?
thanks,
Jay
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这就是我发现的。
来自 eclipse 图形文档：
注意：在每次从 SurfaceHolder 检索 Canvas 时，Canvas 的先前状态将被保留。为了正确地为图形设置动画，您必须重新绘制整个表面。例如，您可以通过使用drawColor()填充颜色或使用drawBitmap()设置背景图像来清除Canvas的先前状态。否则，你会看到你之前绘制的痕迹
所以我使用的代码如下：
在onCreate()中
mBitmapBase = BitmapFactory.decodeResource(getResources(), R.drawable.bidBackground);
在 onSurfaceChanged() 中
// 调整背景位图的大小，以便高效绘制
mBitmapBackground = Bitmap.createScaledBitmap(mBitmapBackground, xMax, yMax, true);
并在 Run() 中
尝试
{
画布 = sHolder.lockCanvas();
if（画布！= null）
canvas.drawBitmap(mBitmapBackground, 0, 0, null);
据我所知，这是尽可能有效的。尽管如果有人能纠正我这一点，我很乐意听到。
This is what I found.
From the eclipse graphic documentation:
Note: On each pass you retrieve the Canvas from the SurfaceHolder, the previous state of the Canvas will be retained. In order to properly animate your graphics, you must re-paint the entire surface. For example, you can clear the previous state of the Canvas by filling in a color with drawColor() or setting a background image with drawBitmap(). Otherwise, you will see traces of the drawings you previously performed
So the code I used is as follows:
in onCreate()
mBitmapBase = BitmapFactory.decodeResource(getResources(), R.drawable.bidBackground);
in onSurfaceChanged()
// size the background bitmap so it draws efficiently
mBitmapBackground = Bitmap.createScaledBitmap(mBitmapBackground, xMax, yMax, true);
and in Run()
try
{
canvas = sHolder.lockCanvas();
if (canvas != null)
canvas.drawBitmap(mBitmapBackground, 0, 0, null);
As far as I can tell this is as efficient as it can get. Although if anybody can correct me on this I would love to hear it.